neovim

drawline.c (122819B)

---

// drawline.c: Functions for drawing window lines on the screen.
// This is the middle level, drawscreen.c is the top and grid.c the lower level.

#include <assert.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "nvim/ascii_defs.h"
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/charset.h"
#include "nvim/cursor.h"
#include "nvim/cursor_shape.h"
#include "nvim/decoration.h"
#include "nvim/decoration_defs.h"
#include "nvim/decoration_provider.h"
#include "nvim/diff.h"
#include "nvim/drawline.h"
#include "nvim/drawscreen.h"
#include "nvim/eval/vars.h"
#include "nvim/fold.h"
#include "nvim/fold_defs.h"
#include "nvim/globals.h"
#include "nvim/grid.h"
#include "nvim/grid_defs.h"
#include "nvim/highlight.h"
#include "nvim/highlight_defs.h"
#include "nvim/highlight_group.h"
#include "nvim/indent.h"
#include "nvim/insexpand.h"
#include "nvim/mark_defs.h"
#include "nvim/marktree_defs.h"
#include "nvim/match.h"
#include "nvim/mbyte.h"
#include "nvim/mbyte_defs.h"
#include "nvim/memline.h"
#include "nvim/memory.h"
#include "nvim/move.h"
#include "nvim/option.h"
#include "nvim/option_vars.h"
#include "nvim/os/os_defs.h"
#include "nvim/plines.h"
#include "nvim/pos_defs.h"
#include "nvim/quickfix.h"
#include "nvim/sign_defs.h"
#include "nvim/spell.h"
#include "nvim/state.h"
#include "nvim/state_defs.h"
#include "nvim/statusline.h"
#include "nvim/statusline_defs.h"
#include "nvim/strings.h"
#include "nvim/syntax.h"
#include "nvim/terminal.h"
#include "nvim/types_defs.h"
#include "nvim/ui.h"
#include "nvim/ui_defs.h"
#include "nvim/vim_defs.h"

#define MB_FILLER_CHAR '<'  // character used when a double-width character doesn't fit.

/// structure with variables passed between win_line() and other functions
typedef struct {
 const linenr_T lnum;       ///< line number to be drawn
 const foldinfo_T foldinfo;  ///< fold info for this line

 const int startrow;        ///< first row in the window to be drawn
 int row;                   ///< row in the window, excl w_winrow

 colnr_T vcol;              ///< virtual column, before wrapping
 int col;                   ///< visual column on screen, after wrapping
 int boguscols;             ///< nonexistent columns added to "col" to force wrapping
 int old_boguscols;         ///< bogus boguscols
 int vcol_off_co;           ///< offset for concealed characters

 int off;                   ///< offset relative start of line

 int cul_attr;              ///< set when 'cursorline' active
 int line_attr;             ///< attribute for the whole line
 int line_attr_lowprio;     ///< low-priority attribute for the line
 int sign_num_attr;         ///< line number attribute (sign numhl)
 int prev_num_attr;         ///< previous line's number attribute (sign numhl)
 int sign_cul_attr;         ///< cursorline sign attribute (sign culhl)

 int fromcol;               ///< start of inverting
 int tocol;                 ///< end of inverting

 colnr_T vcol_sbr;          ///< virtual column after showbreak
 bool need_showbreak;       ///< overlong line, skipping first x chars

 int char_attr;             ///< attributes for next character

 int n_extra;               ///< number of extra bytes
 int n_attr;                ///< chars with special attr
 char *p_extra;             ///< string of extra chars, plus NUL, only used
                            ///< when sc_extra and sc_final are NUL
 int extra_attr;            ///< attributes for p_extra
 schar_T sc_extra;          ///< extra chars, all the same
 schar_T sc_final;          ///< final char, mandatory if set

 bool extra_for_extmark;    ///< n_extra set for inline virtual text

 char extra[11];            ///< must be as large as transchar_charbuf[] in charset.c

 hlf_T diff_hlf;            ///< type of diff highlighting

 int n_virt_lines;          ///< nr of virtual lines
 int n_virt_below;          ///< nr of virtual lines belonging to previous line
 int filler_lines;          ///< nr of filler lines to be drawn
 int filler_todo;           ///< nr of filler lines still to do + 1
 SignTextAttrs sattrs[SIGN_SHOW_MAX];  ///< sign attributes for the sign column
 /// do consider wrapping in linebreak mode only after encountering
 /// a non whitespace char
 bool need_lbr;

 VirtText virt_inline;
 size_t virt_inline_i;
 HlMode virt_inline_hl_mode;

 bool reset_extra_attr;

 int skip_cells;            ///< nr of cells to skip for w_leftcol
                            ///< or w_skipcol or concealing
 int skipped_cells;         ///< nr of skipped cells for virtual text
                            ///< to be added to wlv.vcol later

 int *color_cols;           ///< if not NULL, highlight colorcolumn using according columns array
} winlinevars_T;

#include "drawline.c.generated.h"

static char *extra_buf = NULL;
static size_t extra_buf_size = 0;

static char *get_extra_buf(size_t size)
{
 size = MAX(size, 64);
 if (extra_buf_size < size) {
   xfree(extra_buf);
   extra_buf = xmalloc(size);
   extra_buf_size = size;
 }
 return extra_buf;
}

#ifdef EXITFREE
void drawline_free_all_mem(void)
{
 xfree(extra_buf);
}
#endif

/// Get the 'listchars' "extends" characters to use for "wp", or NUL if it
/// shouldn't be used.
static schar_T get_lcs_ext(win_T *wp)
{
 if (wp->w_p_wrap) {
   // Line never continues beyond the right of the screen with 'wrap'.
   return NUL;
 }
 if (wp->w_p_wrap_flags & kOptFlagInsecure) {
   // If 'nowrap' was set from a modeline, forcibly use '>'.
   return schar_from_ascii('>');
 }
 return wp->w_p_list ? wp->w_p_lcs_chars.ext : NUL;
}

/// Advance wlv->color_cols if not NULL
static void advance_color_col(winlinevars_T *wlv, int vcol)
{
 if (wlv->color_cols) {
   while (*wlv->color_cols >= 0 && vcol > *wlv->color_cols) {
     wlv->color_cols++;
   }
   if (*wlv->color_cols < 0) {
     wlv->color_cols = NULL;
   }
 }
}

/// Used when 'cursorlineopt' contains "screenline": compute the margins between
/// which the highlighting is used.
static void margin_columns_win(win_T *wp, int *left_col, int *right_col)
{
 // cache previous calculations depending on w_virtcol
 static int saved_w_virtcol;
 static win_T *prev_wp;
 static int prev_width1;
 static int prev_width2;
 static int prev_left_col;
 static int prev_right_col;

 int cur_col_off = win_col_off(wp);
 int width1 = wp->w_view_width - cur_col_off;
 int width2 = width1 + win_col_off2(wp);

 if (saved_w_virtcol == wp->w_virtcol && prev_wp == wp
     && prev_width1 == width1 && prev_width2 == width2) {
   *right_col = prev_right_col;
   *left_col = prev_left_col;
   return;
 }

 *left_col = 0;
 *right_col = width1;

 if (wp->w_virtcol >= (colnr_T)width1 && width2 > 0) {
   *right_col = width1 + ((wp->w_virtcol - width1) / width2 + 1) * width2;
 }
 if (wp->w_virtcol >= (colnr_T)width1 && width2 > 0) {
   *left_col = (wp->w_virtcol - width1) / width2 * width2 + width1;
 }

 // cache values
 prev_left_col = *left_col;
 prev_right_col = *right_col;
 prev_wp = wp;
 prev_width1 = width1;
 prev_width2 = width2;
 saved_w_virtcol = wp->w_virtcol;
}

/// Put a single char from an UTF-8 buffer into a line buffer.
///
/// If `*pp` is a double-width char and only one cell is left, emit a space,
/// and don't advance *pp
///
/// Handles composing chars
static int line_putchar(buf_T *buf, const char **pp, schar_T *dest, int maxcells, int vcol)
{
 // Caller should handle overwriting the right half of a double-width char.
 assert(dest[0] != 0);

 const char *p = *pp;
 int cells = utf_ptr2cells(p);
 int c_len = utfc_ptr2len(p);
 assert(maxcells > 0);
 if (cells > maxcells) {
   dest[0] = schar_from_ascii(' ');
   return 1;
 }

 if (*p == TAB) {
   cells = tabstop_padding(vcol, buf->b_p_ts, buf->b_p_vts_array);
   cells = MIN(cells, maxcells);
 }

 // When overwriting the left half of a double-width char, clear the right half.
 if (cells < maxcells && dest[cells] == 0) {
   dest[cells] = schar_from_ascii(' ');
 }
 if (*p == TAB) {
   for (int c = 0; c < cells; c++) {
     dest[c] = schar_from_ascii(' ');
   }
 } else {
   int u8c;
   dest[0] = utfc_ptr2schar(p, &u8c);
   if (cells > 1) {
     dest[1] = 0;
   }
 }

 *pp += c_len;
 return cells;
}

static void draw_virt_text(win_T *wp, buf_T *buf, int col_off, int *end_col, int win_row)
{
 DecorState *const state = &decor_state;
 int const max_col = wp->w_view_width;
 int right_pos = max_col;
 bool const do_eol = state->eol_col > -1;

 int const end = state->current_end;
 int *const indices = state->ranges_i.items;
 DecorRangeSlot *const slots = state->slots.items;

 /// Total width of all virtual text with "eol_right_align" alignment
 int totalWidthOfEolRightAlignedVirtText = 0;

 for (int i = 0; i < end; i++) {
   DecorRange *item = &slots[indices[i]].range;
   if (!(item->start_row == state->row && decor_virt_pos(item))) {
     continue;
   }

   DecorVirtText *vt = NULL;
   if (item->kind == kDecorKindVirtText) {
     assert(item->data.vt);
     vt = item->data.vt;
   }
   if (decor_virt_pos(item) && item->draw_col == -1) {
     bool updated = true;
     VirtTextPos pos = decor_virt_pos_kind(item);

     if (do_eol && pos == kVPosEndOfLineRightAlign) {
       int eolOffset = 0;
       if (totalWidthOfEolRightAlignedVirtText == 0) {
         // Look ahead to the remaining decor items
         for (int j = i; j < end; j++) {
           /// A future decor to be handled in this function's call
           DecorRange *lookaheadItem = &slots[indices[j]].range;

           if (lookaheadItem->start_row != state->row
               || !decor_virt_pos(lookaheadItem)
               || lookaheadItem->draw_col != -1) {
             continue;
           }

           /// The Virtual Text of the decor item we're looking ahead to
           DecorVirtText *lookaheadVt = NULL;
           if (lookaheadItem->kind == kDecorKindVirtText) {
             assert(lookaheadItem->data.vt);
             lookaheadVt = lookaheadItem->data.vt;
           }

           if (decor_virt_pos_kind(lookaheadItem) == kVPosEndOfLineRightAlign) {
             // An extra space is added for single character spacing in EOL alignment
             totalWidthOfEolRightAlignedVirtText += (lookaheadVt->width + 1);
           }
         }

         // Remove one space from the total width since there's no single space after the last entry
         totalWidthOfEolRightAlignedVirtText--;

         if (totalWidthOfEolRightAlignedVirtText <= (right_pos - state->eol_col)) {
           eolOffset = right_pos - totalWidthOfEolRightAlignedVirtText - state->eol_col;
         }
       }

       item->draw_col = state->eol_col + eolOffset;
     } else if (pos == kVPosRightAlign) {
       right_pos -= vt->width;
       item->draw_col = right_pos;
     } else if (pos == kVPosEndOfLine && do_eol) {
       item->draw_col = state->eol_col;
     } else if (pos == kVPosWinCol) {
       item->draw_col = MAX(col_off + vt->col, 0);
     } else {
       updated = false;
     }
     if (updated && (item->draw_col < 0 || item->draw_col >= wp->w_view_width)) {
       // Out of window, don't draw at all.
       item->draw_col = INT_MIN;
     }
   }
   if (item->draw_col < 0) {
     continue;
   }
   if (item->kind == kDecorKindUIWatched) {
     // send mark position to UI
     WinExtmark m = { (NS)item->data.ui.ns_id, item->data.ui.mark_id, win_row, item->draw_col };
     kv_push(win_extmark_arr, m);
   }
   if (vt) {
     int vcol = item->draw_col - col_off;
     int col = draw_virt_text_item(buf, item->draw_col, vt->data.virt_text,
                                   vt->hl_mode, max_col, vcol, 0);
     if (do_eol && ((vt->pos == kVPosEndOfLine) || (vt->pos == kVPosEndOfLineRightAlign))) {
       state->eol_col = col + 1;
     }
     *end_col = MAX(*end_col, col);
   }
   if (!vt || !(vt->flags & kVTRepeatLinebreak)) {
     item->draw_col = INT_MIN;  // deactivate
   }
 }
}

static int draw_virt_text_item(buf_T *buf, int col, VirtText vt, HlMode hl_mode, int max_col,
                              int vcol, int skip_cells)
{
 const char *virt_str = "";
 int virt_attr = 0;
 size_t virt_pos = 0;

 while (col < max_col) {
   if (skip_cells >= 0 && *virt_str == NUL) {
     if (virt_pos >= kv_size(vt)) {
       break;
     }
     virt_attr = 0;
     virt_str = next_virt_text_chunk(vt, &virt_pos, &virt_attr);
     if (virt_str == NULL) {
       break;
     }
   }
   // Skip cells in the text.
   while (skip_cells > 0 && *virt_str != NUL) {
     int c_len = utfc_ptr2len(virt_str);
     int cells = *virt_str == TAB
                 ? tabstop_padding(vcol, buf->b_p_ts, buf->b_p_vts_array)
                 : utf_ptr2cells(virt_str);
     skip_cells -= cells;
     vcol += cells;
     virt_str += c_len;
   }
   // If a double-width char or TAB doesn't fit, pad with spaces.
   const char *draw_str = skip_cells < 0 ? " " : virt_str;
   if (*draw_str == NUL) {
     continue;
   }
   assert(skip_cells <= 0);
   int attr;
   bool through = false;
   if (hl_mode == kHlModeCombine) {
     attr = hl_combine_attr(linebuf_attr[col], virt_attr);
   } else if (hl_mode == kHlModeBlend) {
     through = (*draw_str == ' ');
     attr = hl_blend_attrs(linebuf_attr[col], virt_attr, &through);
   } else {
     attr = virt_attr;
   }
   schar_T dummy[2] = { schar_from_ascii(' '), schar_from_ascii(' ') };
   int maxcells = max_col - col;
   // When overwriting the right half of a double-width char, clear the left half.
   if (!through && linebuf_char[col] == 0) {
     assert(col > 0);
     linebuf_char[col - 1] = schar_from_ascii(' ');
     // Clear the right half as well for the assertion in line_putchar().
     linebuf_char[col] = schar_from_ascii(' ');
   }
   int cells = line_putchar(buf, &draw_str, through ? dummy : &linebuf_char[col],
                            maxcells, vcol);
   for (int c = 0; c < cells; c++) {
     linebuf_attr[col] = attr;
     col++;
   }
   if (skip_cells < 0) {
     skip_cells++;
   } else {
     vcol += cells;
     virt_str = draw_str;
   }
 }
 return col;
}

// TODO(bfredl): integrate with grid.c linebuf code? madness?
static void draw_col_buf(win_T *wp, winlinevars_T *wlv, const char *text, size_t len, int attr,
                        const colnr_T *fold_vcol, bool inc_vcol)
{
 const char *ptr = text;
 while (ptr < text + len && wlv->off < wp->w_view_width) {
   int cells = line_putchar(wp->w_buffer, &ptr, &linebuf_char[wlv->off],
                            wp->w_view_width - wlv->off, wlv->off);
   int myattr = attr;
   if (inc_vcol) {
     advance_color_col(wlv, wlv->vcol);
     if (wlv->color_cols && wlv->vcol == *wlv->color_cols) {
       myattr = hl_combine_attr(win_hl_attr(wp, HLF_MC), myattr);
     }
   }
   for (int c = 0; c < cells; c++) {
     linebuf_attr[wlv->off] = myattr;
     linebuf_vcol[wlv->off] = inc_vcol ? wlv->vcol++ : fold_vcol ? *(fold_vcol++) : -1;
     wlv->off++;
   }
 }
}

static void draw_col_fill(winlinevars_T *wlv, schar_T fillchar, int width, int attr)
{
 for (int i = 0; i < width; i++) {
   linebuf_char[wlv->off] = fillchar;
   linebuf_attr[wlv->off] = attr;
   wlv->off++;
 }
}

/// Return true if CursorLineSign highlight is to be used.
bool use_cursor_line_highlight(win_T *wp, linenr_T lnum)
{
 return wp->w_p_cul
        && lnum == wp->w_cursorline
        && (wp->w_p_culopt_flags & kOptCuloptFlagNumber);
}

/// Setup for drawing the 'foldcolumn', if there is one.
static void draw_foldcolumn(win_T *wp, winlinevars_T *wlv)
{
 int fdc = compute_foldcolumn(wp, 0);
 if (fdc > 0) {
   int attr = win_hl_attr(wp, use_cursor_line_highlight(wp, wlv->lnum) ? HLF_CLF : HLF_FC);
   fill_foldcolumn(wp, wlv->foldinfo, wlv->lnum, attr, fdc, &wlv->off, NULL, NULL);
 }
}

/// Draw the foldcolumn or fill "out_buffer". Assume monocell characters.
///
/// @param fdc  Current width of the foldcolumn
/// @param[out] wlv_off  Pointer to linebuf offset, incremented for default column
/// @param[out] out_buffer  Char array to fill, only used for 'statuscolumn'
/// @param[out] out_vcol  vcol array to fill, only used for 'statuscolumn'
void fill_foldcolumn(win_T *wp, foldinfo_T foldinfo, linenr_T lnum, int attr, int fdc, int *wlv_off,
                    colnr_T *out_vcol, schar_T *out_buffer)
{
 bool closed = foldinfo.fi_level != 0 && foldinfo.fi_lines > 0;
 int level = foldinfo.fi_level;

 // If the column is too narrow, we start at the lowest level that
 // fits and use numbers to indicate the depth.
 int first_level = MAX(level - fdc - closed + 1, 1);
 int closedcol = MIN(fdc, level);

 for (int i = 0; i < fdc; i++) {
   schar_T symbol = 0;
   if (i >= level) {
     symbol = schar_from_ascii(' ');
   } else if (i == closedcol - 1 && closed) {
     symbol = wp->w_p_fcs_chars.foldclosed;
   } else if (foldinfo.fi_lnum == lnum && first_level + i >= foldinfo.fi_low_level) {
     symbol = wp->w_p_fcs_chars.foldopen;
   } else if (first_level == 1) {
     symbol = wp->w_p_fcs_chars.foldsep;
   } else if (wp->w_p_fcs_chars.foldinner != NUL) {
     symbol = wp->w_p_fcs_chars.foldinner;
   } else if (first_level + i <= 9) {
     symbol = schar_from_ascii('0' + first_level + i);
   } else {
     symbol = schar_from_ascii('>');
   }

   int vcol = i >= level ? -1 : (i == closedcol - 1 && closed) ? -2 : -3;
   if (out_buffer) {
     out_vcol[i] = vcol;
     out_buffer[i] = symbol;
   } else {
     linebuf_vcol[*wlv_off] = vcol;
     linebuf_attr[*wlv_off] = attr;
     linebuf_char[(*wlv_off)++] = symbol;
   }
 }
}

/// Get information needed to display the sign in line "wlv->lnum" in window "wp".
/// If "nrcol" is true, the sign is going to be displayed in the number column.
/// Otherwise the sign is going to be displayed in the sign column. If there is no
/// sign, draw blank cells instead.
static void draw_sign(bool nrcol, win_T *wp, winlinevars_T *wlv, int sign_idx)
{
 SignTextAttrs sattr = wlv->sattrs[sign_idx];
 int scl_attr = win_hl_attr(wp, use_cursor_line_highlight(wp, wlv->lnum) ? HLF_CLS : HLF_SC);

 if (sattr.text[0] && wlv->row == wlv->startrow + wlv->filler_lines && wlv->filler_todo <= 0) {
   int fill = nrcol ? number_width(wp) + 1 : SIGN_WIDTH;
   int attr = wlv->sign_cul_attr ? wlv->sign_cul_attr : sattr.hl_id ? syn_id2attr(sattr.hl_id) : 0;
   attr = hl_combine_attr(scl_attr, attr);
   draw_col_fill(wlv, schar_from_ascii(' '), fill, attr);
   int sign_pos = wlv->off - SIGN_WIDTH - (int)nrcol;
   assert(sign_pos >= 0);
   linebuf_char[sign_pos] = sattr.text[0];
   linebuf_char[sign_pos + 1] = sattr.text[1];
 } else {
   assert(!nrcol);  // handled in draw_lnum_col()
   draw_col_fill(wlv, schar_from_ascii(' '), SIGN_WIDTH, scl_attr);
 }
}

static inline void get_line_number_str(win_T *wp, linenr_T lnum, char *buf, size_t buf_len)
{
 linenr_T num;
 char *fmt = "%*" PRIdLINENR " ";

 if (wp->w_p_nu && !wp->w_p_rnu) {
   // 'number' + 'norelativenumber'
   num = lnum;
 } else {
   // 'relativenumber', don't use negative numbers
   num = abs(get_cursor_rel_lnum(wp, lnum));
   if (num == 0 && wp->w_p_nu && wp->w_p_rnu) {
     // 'number' + 'relativenumber'
     num = lnum;
     fmt = "%-*" PRIdLINENR " ";
   }
 }

 snprintf(buf, buf_len, fmt, number_width(wp), num);
}

/// Return true if CursorLineNr highlight is to be used for the number column.
/// - 'cursorline' must be set
/// - "wlv->lnum" must be the cursor line
/// - 'cursorlineopt' has "number"
/// - don't highlight filler lines (when in diff mode)
/// - When line is wrapped and 'cursorlineopt' does not have "line", only highlight the line number
///   itself on the first screenline of the wrapped line, otherwise highlight the number column of
///   all screenlines of the wrapped line.
static bool use_cursor_line_nr(win_T *wp, winlinevars_T *wlv)
{
 return wp->w_p_cul
        && wlv->lnum == wp->w_cursorline
        && (wp->w_p_culopt_flags & kOptCuloptFlagNumber)
        && (wlv->row == wlv->startrow + wlv->filler_lines
            || (wlv->row > wlv->startrow + wlv->filler_lines
                && (wp->w_p_culopt_flags & kOptCuloptFlagLine)));
}

/// Return line number attribute, combining the appropriate LineNr* highlight
/// with the highest priority sign numhl highlight, if any.
static int get_line_number_attr(win_T *wp, winlinevars_T *wlv)
{
 int numhl_attr = wlv->sign_num_attr;

 // Get previous sign numhl for virt_lines belonging to the previous line.
 if ((wlv->n_virt_lines - wlv->filler_todo) < wlv->n_virt_below) {
   if (wlv->prev_num_attr == -1) {
     decor_redraw_signs(wp, wp->w_buffer, wlv->lnum - 2, NULL, NULL, NULL, &wlv->prev_num_attr);
     if (wlv->prev_num_attr > 0) {
       wlv->prev_num_attr = syn_id2attr(wlv->prev_num_attr);
     }
   }
   numhl_attr = wlv->prev_num_attr;
 }

 if (use_cursor_line_nr(wp, wlv)) {
   // TODO(vim): Can we use CursorLine instead of CursorLineNr
   // when CursorLineNr isn't set?
   return hl_combine_attr(win_hl_attr(wp, HLF_CLN), numhl_attr);
 }

 if (wp->w_p_rnu) {
   if (wlv->lnum < wp->w_cursor.lnum) {
     // Use LineNrAbove
     return hl_combine_attr(win_hl_attr(wp, HLF_LNA), numhl_attr);
   }
   if (wlv->lnum > wp->w_cursor.lnum) {
     // Use LineNrBelow
     return hl_combine_attr(win_hl_attr(wp, HLF_LNB), numhl_attr);
   }
 }

 return hl_combine_attr(win_hl_attr(wp, HLF_N), numhl_attr);
}

/// Display the absolute or relative line number.  After the first row fill with
/// blanks when the 'n' flag isn't in 'cpo'.
static void draw_lnum_col(win_T *wp, winlinevars_T *wlv)
{
 bool has_cpo_n = vim_strchr(p_cpo, CPO_NUMCOL) != NULL;

 if ((wp->w_p_nu || wp->w_p_rnu)
     && (wlv->row == wlv->startrow + wlv->filler_lines || !has_cpo_n)
     // there is no line number in a wrapped line when "n" is in
     // 'cpoptions', but 'breakindent' assumes it anyway.
     && !((has_cpo_n && !wp->w_p_bri) && wp->w_skipcol > 0 && wlv->lnum == wp->w_topline)) {
   // If 'signcolumn' is set to 'number' and a sign is present in "lnum",
   // then display the sign instead of the line number.
   if (wp->w_minscwidth == SCL_NUM && wlv->sattrs[0].text[0]
       && wlv->row == wlv->startrow + wlv->filler_lines && wlv->filler_todo <= 0) {
     draw_sign(true, wp, wlv, 0);
   } else {
     // Draw the line number (empty space after wrapping).
     int width = number_width(wp) + 1;
     int attr = get_line_number_attr(wp, wlv);
     if (wlv->row == wlv->startrow + wlv->filler_lines
         && (wp->w_skipcol == 0 || wlv->row > 0 || (wp->w_p_nu && wp->w_p_rnu))) {
       char buf[32];
       get_line_number_str(wp, wlv->lnum, buf, sizeof(buf));
       if (wp->w_skipcol > 0 && wlv->startrow == 0) {
         for (char *c = buf; *c == ' '; c++) {
           *c = '-';
         }
       }
       if (wp->w_p_rl) {  // reverse line numbers
         char *num = skipwhite(buf);
         rl_mirror_ascii(num, skiptowhite(num));
       }
       draw_col_buf(wp, wlv, buf, (size_t)width, attr, NULL, false);
     } else {
       draw_col_fill(wlv, schar_from_ascii(' '), width, attr);
     }
   }
 }
}

/// Build and draw the 'statuscolumn' string for line "lnum" in window "wp".
static void draw_statuscol(win_T *wp, winlinevars_T *wlv, int virtnum, int col_rows,
                          statuscol_T *stcp)
{
 // Adjust lnum for filler lines belonging to the line above and set lnum v:vars for first
 // row, first non-filler line, and first filler line belonging to the current line.
 linenr_T lnum = wlv->lnum - ((wlv->n_virt_lines - wlv->filler_todo) < wlv->n_virt_below);
 linenr_T relnum = (virtnum == -wlv->filler_lines || virtnum == 0
                    || virtnum == (wlv->n_virt_below - wlv->filler_lines))
                   ? abs(get_cursor_rel_lnum(wp, lnum)) : -1;

 char buf[MAXPATHL];
 // When a buffer's line count has changed, make a best estimate for the full
 // width of the status column by building with the largest possible line number.
 // Add potentially truncated width and rebuild before drawing anything.
 if (wp->w_statuscol_line_count != wp->w_nrwidth_line_count) {
   wp->w_statuscol_line_count = wp->w_nrwidth_line_count;
   set_vim_var_nr(VV_VIRTNUM, 0);
   int width = build_statuscol_str(wp, wp->w_nrwidth_line_count,
                                   wp->w_nrwidth_line_count, buf, stcp);
   if (width > stcp->width) {
     int addwidth = MIN(width - stcp->width, MAX_STCWIDTH - stcp->width);
     wp->w_nrwidth += addwidth;
     wp->w_nrwidth_width = wp->w_nrwidth;
     if (col_rows > 0) {
       // If only column is being redrawn, we now need to redraw the text as well
       wp->w_redr_statuscol = true;
       return;
     }
     stcp->width += addwidth;
     wp->w_valid &= ~VALID_WCOL;
   }
 }
 set_vim_var_nr(VV_VIRTNUM, virtnum);

 int width = build_statuscol_str(wp, lnum, relnum, buf, stcp);
 // Force a redraw in case of error or when truncated
 if (*wp->w_p_stc == NUL || (width > stcp->width && stcp->width < MAX_STCWIDTH)) {
   if (*wp->w_p_stc == NUL) {  // 'statuscolumn' reset due to error
     wp->w_nrwidth_line_count = 0;
     wp->w_nrwidth = (wp->w_p_nu || wp->w_p_rnu) * number_width(wp);
   } else {  // Avoid truncating 'statuscolumn'
     wp->w_nrwidth += MIN(width - stcp->width, MAX_STCWIDTH - stcp->width);
     wp->w_nrwidth_width = wp->w_nrwidth;
   }
   wp->w_redr_statuscol = true;
   return;
 }

 char *p = buf;
 char transbuf[MAXPATHL];
 colnr_T *fold_vcol = NULL;
 size_t len = strlen(buf);
 int scl_attr = win_hl_attr(wp, use_cursor_line_highlight(wp, wlv->lnum) ? HLF_CLS : HLF_SC);
 int num_attr = get_line_number_attr(wp, wlv);
 int cur_attr = num_attr;

 // Draw each segment with the specified highlighting.
 for (stl_hlrec_t *sp = stcp->hlrec; sp->start != NULL; sp++) {
   ptrdiff_t textlen = sp->start - p;
   // Make all characters printable.
   size_t translen = transstr_buf(p, textlen, transbuf, MAXPATHL, true);
   draw_col_buf(wp, wlv, transbuf, translen, cur_attr, fold_vcol, false);
   int attr = sp->item == STL_SIGNCOL ? scl_attr : sp->item == STL_FOLDCOL ? 0 : num_attr;
   cur_attr = hl_combine_attr(attr, sp->userhl < 0 ? syn_id2attr(-sp->userhl) : 0);
   fold_vcol = sp->item == STL_FOLDCOL ? stcp->fold_vcol : NULL;
   p = sp->start;
 }
 size_t translen = transstr_buf(p, buf + len - p, transbuf, MAXPATHL, true);
 draw_col_buf(wp, wlv, transbuf, translen, cur_attr, fold_vcol, false);
 draw_col_fill(wlv, schar_from_ascii(' '), stcp->width - width, cur_attr);
}

static void handle_breakindent(win_T *wp, winlinevars_T *wlv)
{
 // draw 'breakindent': indent wrapped text accordingly
 // if wlv->need_showbreak is set, breakindent also applies
 if (wp->w_p_bri && (wlv->row > wlv->startrow + wlv->filler_lines
                     || wlv->need_showbreak)) {
   int attr = 0;
   if (wlv->diff_hlf != (hlf_T)0) {
     attr = win_hl_attr(wp, (int)wlv->diff_hlf);
   }
   int num = get_breakindent_win(wp, ml_get_buf(wp->w_buffer, wlv->lnum));
   if (wlv->row == wlv->startrow) {
     num -= win_col_off2(wp);
     if (wlv->n_extra < 0) {
       num = 0;
     }
   }

   colnr_T vcol_before = wlv->vcol;

   for (int i = 0; i < num; i++) {
     linebuf_char[wlv->off] = schar_from_ascii(' ');

     advance_color_col(wlv, wlv->vcol);
     int myattr = attr;
     if (wlv->color_cols && wlv->vcol == *wlv->color_cols) {
       myattr = hl_combine_attr(win_hl_attr(wp, HLF_MC), myattr);
     }
     linebuf_attr[wlv->off] = myattr;
     linebuf_vcol[wlv->off] = wlv->vcol++;  // These are vcols, sorry I don't make the rules
     wlv->off++;
   }

   // Correct start of highlighted area for 'breakindent',
   if (wlv->fromcol >= vcol_before && wlv->fromcol < wlv->vcol) {
     wlv->fromcol = wlv->vcol;
   }

   // Correct end of highlighted area for 'breakindent',
   // required wen 'linebreak' is also set.
   if (wlv->tocol == vcol_before) {
     wlv->tocol = wlv->vcol;
   }
 }

 if (wp->w_skipcol > 0 && wlv->startrow == 0 && wp->w_p_wrap && wp->w_briopt_sbr) {
   wlv->need_showbreak = false;
 }
}

static void handle_showbreak_and_filler(win_T *wp, winlinevars_T *wlv)
{
 int remaining = wp->w_view_width - wlv->off;
 if (wlv->filler_todo > wlv->filler_lines - wlv->n_virt_lines) {
   // TODO(bfredl): check this doesn't inhibit TUI-style
   //               clear-to-end-of-line.
   draw_col_fill(wlv, schar_from_ascii(' '), remaining, 0);
 } else if (wlv->filler_todo > 0) {
   // Draw "deleted" diff line(s)
   schar_T c = wp->w_p_fcs_chars.diff;
   draw_col_fill(wlv, c, remaining, win_hl_attr(wp, HLF_DED));
 }

 char *const sbr = get_showbreak_value(wp);
 if (*sbr != NUL && wlv->need_showbreak) {
   // Draw 'showbreak' at the start of each broken line.
   // Combine 'showbreak' with 'cursorline', prioritizing 'showbreak'.
   int attr = hl_combine_attr(wlv->cul_attr, win_hl_attr(wp, HLF_AT));
   colnr_T vcol_before = wlv->vcol;
   draw_col_buf(wp, wlv, sbr, strlen(sbr), attr, NULL, true);
   wlv->vcol_sbr = wlv->vcol;

   // Correct start of highlighted area for 'showbreak'.
   if (wlv->fromcol >= vcol_before && wlv->fromcol < wlv->vcol) {
     wlv->fromcol = wlv->vcol;
   }

   // Correct end of highlighted area for 'showbreak',
   // required when 'linebreak' is also set.
   if (wlv->tocol == vcol_before) {
     wlv->tocol = wlv->vcol;
   }
 }

 if (wp->w_skipcol == 0 || wlv->startrow > 0 || !wp->w_p_wrap || !wp->w_briopt_sbr) {
   wlv->need_showbreak = false;
 }
}

static void apply_cursorline_highlight(win_T *wp, winlinevars_T *wlv)
{
 wlv->cul_attr = win_hl_attr(wp, HLF_CUL);
 HlAttrs ae = syn_attr2entry(wlv->cul_attr);
 // We make a compromise here (#7383):
 //  * low-priority CursorLine if fg is not set
 //  * high-priority ("same as Vim" priority) CursorLine if fg is set
 if (ae.rgb_fg_color == -1 && ae.cterm_fg_color == 0) {
   wlv->line_attr_lowprio = wlv->cul_attr;
 } else {
   if (!(State & MODE_INSERT) && bt_quickfix(wp->w_buffer)
       && qf_current_entry(wp) == wlv->lnum) {
     wlv->line_attr = hl_combine_attr(wlv->cul_attr, wlv->line_attr);
   } else {
     wlv->line_attr = wlv->cul_attr;
   }
 }
}

static void set_line_attr_for_diff(win_T *wp, winlinevars_T *wlv)
{
 wlv->line_attr = win_hl_attr(wp, (int)wlv->diff_hlf);
 // Overlay CursorLine onto diff-mode highlight.
 if (wlv->cul_attr) {
   wlv->line_attr = 0 != wlv->line_attr_lowprio  // Low-priority CursorLine
                    ? hl_combine_attr(hl_combine_attr(wlv->cul_attr, wlv->line_attr),
                                      hl_get_underline())
                    : hl_combine_attr(wlv->line_attr, wlv->cul_attr);
 }
}

/// Checks if there is more inline virtual text that need to be drawn.
static bool has_more_inline_virt(winlinevars_T *wlv, ptrdiff_t v)
{
 if (wlv->virt_inline_i < kv_size(wlv->virt_inline)) {
   return true;
 }

 int const count = (int)kv_size(decor_state.ranges_i);
 int const cur_end = decor_state.current_end;
 int const fut_beg = decor_state.future_begin;
 int *const indices = decor_state.ranges_i.items;
 DecorRangeSlot *const slots = decor_state.slots.items;

 int const beg_pos[] = { 0, fut_beg };
 int const end_pos[] = { cur_end, count };

 for (int pos_i = 0; pos_i < 2; pos_i++) {
   for (int i = beg_pos[pos_i]; i < end_pos[pos_i]; i++) {
     DecorRange *item = &slots[indices[i]].range;
     if (item->start_row != decor_state.row
         || item->kind != kDecorKindVirtText
         || item->data.vt->pos != kVPosInline
         || item->data.vt->width == 0) {
       continue;
     }
     if (item->draw_col >= -1 && item->start_col >= v) {
       return true;
     }
   }
 }
 return false;
}

static void handle_inline_virtual_text(win_T *wp, winlinevars_T *wlv, ptrdiff_t v, bool selected)
{
 while (wlv->n_extra == 0) {
   if (wlv->virt_inline_i >= kv_size(wlv->virt_inline)) {
     // need to find inline virtual text
     wlv->virt_inline = VIRTTEXT_EMPTY;
     wlv->virt_inline_i = 0;
     DecorState *state = &decor_state;
     int const end = state->current_end;
     int *const indices = state->ranges_i.items;
     DecorRangeSlot *const slots = state->slots.items;

     for (int i = 0; i < end; i++) {
       DecorRange *item = &slots[indices[i]].range;
       if (item->draw_col == -3) {
         // No more inline virtual text before this non-inline virtual text item,
         // so its position can be decided now.
         decor_init_draw_col(wlv->off, selected, item);
       }
       if (item->start_row != state->row
           || item->kind != kDecorKindVirtText
           || item->data.vt->pos != kVPosInline
           || item->data.vt->width == 0) {
         continue;
       }
       if (item->draw_col >= -1 && item->start_col == v) {
         wlv->virt_inline = item->data.vt->data.virt_text;
         wlv->virt_inline_hl_mode = item->data.vt->hl_mode;
         item->draw_col = INT_MIN;
         break;
       }
     }
     if (!kv_size(wlv->virt_inline)) {
       // no more inline virtual text here
       break;
     }
   } else {
     // already inside existing inline virtual text with multiple chunks
     int attr = 0;
     char *text = next_virt_text_chunk(wlv->virt_inline, &wlv->virt_inline_i, &attr);
     if (text == NULL) {
       continue;
     }
     wlv->p_extra = text;
     wlv->n_extra = (int)strlen(text);
     if (wlv->n_extra == 0) {
       continue;
     }
     wlv->sc_extra = NUL;
     wlv->sc_final = NUL;
     wlv->extra_attr = attr;
     wlv->n_attr = mb_charlen(text);
     // If the text didn't reach until the first window
     // column we need to skip cells.
     if (wlv->skip_cells > 0) {
       int virt_text_width = (int)mb_string2cells(wlv->p_extra);
       if (virt_text_width > wlv->skip_cells) {
         int skip_cells_remaining = wlv->skip_cells;
         // Skip cells in the text.
         while (skip_cells_remaining > 0) {
           int cells = utf_ptr2cells(wlv->p_extra);
           if (cells > skip_cells_remaining) {
             break;
           }
           int c_len = utfc_ptr2len(wlv->p_extra);
           skip_cells_remaining -= cells;
           wlv->p_extra += c_len;
           wlv->n_extra -= c_len;
           wlv->n_attr--;
         }
         // Skipped cells needed to be accounted for in vcol.
         wlv->skipped_cells += wlv->skip_cells - skip_cells_remaining;
         wlv->skip_cells = skip_cells_remaining;
       } else {
         // The whole text is left of the window, drop
         // it and advance to the next one.
         wlv->skip_cells -= virt_text_width;
         // Skipped cells needed to be accounted for in vcol.
         wlv->skipped_cells += virt_text_width;
         wlv->n_attr = 0;
         wlv->n_extra = 0;
         // Go to the start so the next virtual text chunk can be selected.
         continue;
       }
     }
     assert(wlv->n_extra > 0);
     wlv->extra_for_extmark = true;
   }
 }
}

/// Start a screen line at column zero.
static void win_line_start(win_T *wp, winlinevars_T *wlv)
{
 wlv->col = 0;
 wlv->off = 0;
 wlv->need_lbr = false;
 for (int i = 0; i < wp->w_view_width; i++) {
   linebuf_char[i] = schar_from_ascii(' ');
   linebuf_attr[i] = 0;
   linebuf_vcol[i] = -1;
 }
}

static void fix_for_boguscols(winlinevars_T *wlv)
{
 wlv->n_extra += wlv->vcol_off_co;
 wlv->vcol -= wlv->vcol_off_co;
 wlv->vcol_off_co = 0;
 wlv->col -= wlv->boguscols;
 wlv->old_boguscols = wlv->boguscols;
 wlv->boguscols = 0;
}

static int get_rightmost_vcol(win_T *wp, const int *color_cols)
{
 int ret = 0;

 if (wp->w_p_cuc) {
   ret = wp->w_virtcol;
 }

 if (color_cols) {
   // determine rightmost colorcolumn to possibly draw
   for (int i = 0; color_cols[i] >= 0; i++) {
     ret = MAX(ret, color_cols[i]);
   }
 }

 return ret;
}

/// Display line "lnum" of window "wp" on the screen.
/// wp->w_virtcol needs to be valid.
///
/// @param lnum         line to display
/// @param startrow     first row relative to window grid
/// @param endrow       last grid row to be redrawn
/// @param col_rows     set to the height of the line when only updating the columns,
///                     otherwise set to 0
/// @param concealed    only draw virtual lines belonging to the line above
/// @param spv          'spell' related variables kept between calls for "wp"
/// @param foldinfo     fold info for this line
/// @param[in, out] providers  decoration providers active this line
///                            items will be disables if they cause errors
///                            or explicitly return `false`.
///
/// @return             the number of last row the line occupies.
int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int col_rows, bool concealed,
            spellvars_T *spv, foldinfo_T foldinfo)
{
 colnr_T vcol_prev = -1;             // "wlv.vcol" of previous character
 GridView *grid = &wp->w_grid;       // grid specific to the window
 const int view_width = wp->w_view_width;
 const int view_height = wp->w_view_height;

 const bool in_curline = wp == curwin && lnum == curwin->w_cursor.lnum;
 const bool has_fold = foldinfo.fi_level != 0 && foldinfo.fi_lines > 0;
 const bool has_foldtext = has_fold && *wp->w_p_fdt != NUL;

 const bool is_wrapped = wp->w_p_wrap
                         && !has_fold;       // Never wrap folded lines

 int saved_attr2 = 0;                  // char_attr saved for n_attr
 int n_attr3 = 0;                      // chars with overruling special attr
 int saved_attr3 = 0;                  // char_attr saved for n_attr3

 int fromcol_prev = -2;                // start of inverting after cursor
 bool noinvcur = false;                // don't invert the cursor
 bool lnum_in_visual_area = false;

 int char_attr_pri = 0;                // attributes with high priority
 int char_attr_base = 0;               // attributes with low priority
 bool area_highlighting = false;       // Visual or incsearch highlighting in this line
 int vi_attr = 0;                      // attributes for Visual and incsearch highlighting
 int area_attr = 0;                    // attributes desired by highlighting
 int search_attr = 0;                  // attributes desired by 'hlsearch' or ComplMatchIns
 int vcol_save_attr = 0;               // saved attr for 'cursorcolumn'
 int decor_attr = 0;                   // attributes desired by syntax and extmarks
 bool has_syntax = false;              // this buffer has syntax highl.
 int folded_attr = 0;                  // attributes for folded line
 int eol_hl_off = 0;                   // 1 if highlighted char after EOL
#define SPWORDLEN 150
 char nextline[SPWORDLEN * 2];         // text with start of the next line
 int nextlinecol = 0;                  // column where nextline[] starts
 int nextline_idx = 0;                 // index in nextline[] where next line
                                       // starts
 int spell_attr = 0;                   // attributes desired by spelling
 int word_end = 0;                     // last byte with same spell_attr
 int cur_checked_col = 0;              // checked column for current line
 bool extra_check = false;             // has extra highlighting
 int multi_attr = 0;                   // attributes desired by multibyte
 int mb_l = 1;                         // multi-byte byte length
 int mb_c = 0;                         // decoded multi-byte character
 schar_T mb_schar = 0;                 // complete screen char
 int change_start = MAXCOL;            // first col of changed area
 int change_end = -1;                  // last col of changed area
 bool in_multispace = false;           // in multiple consecutive spaces
 int multispace_pos = 0;               // position in lcs-multispace string

 int n_extra_next = 0;                 // n_extra to use after current extra chars
 int extra_attr_next = -1;             // extra_attr to use after current extra chars

 bool search_attr_from_match = false;  // if search_attr is from :match
 bool has_decor = false;               // this buffer has decoration

 int saved_search_attr = 0;            // search_attr to be used when n_extra goes to zero
 int saved_area_attr = 0;              // idem for area_attr
 int saved_decor_attr = 0;             // idem for decor_attr
 bool saved_search_attr_from_match = false;

 int win_col_offset = 0;               // offset for window columns
 bool area_active = false;             // whether in Visual selection, for virtual text
 bool decor_need_recheck = false;      // call decor_recheck_draw_col() at next char

 char buf_fold[FOLD_TEXT_LEN];         // Hold value returned by get_foldtext
 VirtText fold_vt = VIRTTEXT_EMPTY;
 char *foldtext_free = NULL;

 // 'cursorlineopt' has "screenline" and cursor is in this line
 bool cul_screenline = false;
 // margin columns for the screen line, needed for when 'cursorlineopt'
 // contains "screenline"
 int left_curline_col = 0;
 int right_curline_col = 0;

 int match_conc = 0;              ///< cchar for match functions
 bool on_last_col = false;
 int syntax_flags = 0;
 int syntax_seqnr = 0;
 int prev_syntax_id = 0;
 int conceal_attr = win_hl_attr(wp, HLF_CONCEAL);
 bool is_concealing = false;
 bool did_wcol = false;
#define vcol_hlc(wlv) ((wlv).vcol - (wlv).vcol_off_co)

 assert(startrow < endrow);

 // variables passed between functions
 winlinevars_T wlv = {
   .lnum = lnum,
   .foldinfo = foldinfo,
   .startrow = startrow,
   .row = startrow,
   .fromcol = -10,
   .tocol = MAXCOL,
   .vcol_sbr = -1,
   .old_boguscols = 0,
   .prev_num_attr = -1,
 };

 buf_T *buf = wp->w_buffer;
 // Not drawing text when line is concealed or drawing filler lines beyond last line.
 const bool draw_text = !concealed && (lnum != buf->b_ml.ml_line_count + 1);

 int decor_provider_end_col;
 bool check_decor_providers = false;

 if (col_rows == 0 && draw_text) {
   // To speed up the loop below, set extra_check when there is linebreak,
   // trailing white space and/or syntax processing to be done.
   extra_check = wp->w_p_lbr;
   if (syntax_present(wp) && !wp->w_s->b_syn_error && !wp->w_s->b_syn_slow && !has_foldtext) {
     // Prepare for syntax highlighting in this line.  When there is an
     // error, stop syntax highlighting.
     int save_did_emsg = did_emsg;
     did_emsg = false;
     syntax_start(wp, lnum);
     if (did_emsg) {
       wp->w_s->b_syn_error = true;
     } else {
       did_emsg = save_did_emsg;
       if (!wp->w_s->b_syn_slow) {
         has_syntax = true;
         extra_check = true;
       }
     }
   }

   check_decor_providers = true;

   // Check for columns to display for 'colorcolumn'.
   wlv.color_cols = wp->w_buffer->terminal ? NULL : wp->w_p_cc_cols;
   advance_color_col(&wlv, vcol_hlc(wlv));

   // handle Visual active in this window
   if (VIsual_active && wp->w_buffer == curwin->w_buffer) {
     pos_T *top, *bot;

     if (ltoreq(curwin->w_cursor, VIsual)) {
       // Visual is after curwin->w_cursor
       top = &curwin->w_cursor;
       bot = &VIsual;
     } else {
       // Visual is before curwin->w_cursor
       top = &VIsual;
       bot = &curwin->w_cursor;
     }
     lnum_in_visual_area = (lnum >= top->lnum && lnum <= bot->lnum);
     if (VIsual_mode == Ctrl_V) {
       // block mode
       if (lnum_in_visual_area) {
         wlv.fromcol = wp->w_old_cursor_fcol;
         wlv.tocol = wp->w_old_cursor_lcol;
       }
     } else {
       // non-block mode
       if (lnum > top->lnum && lnum <= bot->lnum) {
         wlv.fromcol = 0;
       } else if (lnum == top->lnum) {
         if (VIsual_mode == 'V') {       // linewise
           wlv.fromcol = 0;
         } else {
           getvvcol(wp, top, (colnr_T *)&wlv.fromcol, NULL, NULL);
           if (gchar_pos(top) == NUL) {
             wlv.tocol = wlv.fromcol + 1;
           }
         }
       }
       if (VIsual_mode != 'V' && lnum == bot->lnum) {
         if (*p_sel == 'e' && bot->col == 0
             && bot->coladd == 0) {
           wlv.fromcol = -10;
           wlv.tocol = MAXCOL;
         } else if (bot->col == MAXCOL) {
           wlv.tocol = MAXCOL;
         } else {
           pos_T pos = *bot;
           if (*p_sel == 'e') {
             getvvcol(wp, &pos, (colnr_T *)&wlv.tocol, NULL, NULL);
           } else {
             getvvcol(wp, &pos, NULL, NULL, (colnr_T *)&wlv.tocol);
             wlv.tocol++;
           }
         }
       }
     }

     // Check if the char under the cursor should be inverted (highlighted).
     if (!highlight_match && in_curline
         && cursor_is_block_during_visual(*p_sel == 'e')) {
       noinvcur = true;
     }

     // if inverting in this line set area_highlighting
     if (wlv.fromcol >= 0) {
       area_highlighting = true;
       vi_attr = win_hl_attr(wp, HLF_V);
     }
     // handle 'incsearch' and ":s///c" highlighting
   } else if (highlight_match
              && wp == curwin
              && !has_foldtext
              && lnum >= curwin->w_cursor.lnum
              && lnum <= curwin->w_cursor.lnum + search_match_lines) {
     if (lnum == curwin->w_cursor.lnum) {
       getvcol(curwin, &(curwin->w_cursor),
               (colnr_T *)&wlv.fromcol, NULL, NULL);
     } else {
       wlv.fromcol = 0;
     }
     if (lnum == curwin->w_cursor.lnum + search_match_lines) {
       pos_T pos = {
         .lnum = lnum,
         .col = search_match_endcol,
       };
       getvcol(curwin, &pos, (colnr_T *)&wlv.tocol, NULL, NULL);
     }
     // do at least one character; happens when past end of line
     if (wlv.fromcol == wlv.tocol && search_match_endcol) {
       wlv.tocol = wlv.fromcol + 1;
     }
     area_highlighting = true;
     vi_attr = win_hl_attr(wp, HLF_I);
   }
 }

 int bg_attr = win_bg_attr(wp);

 int linestatus = 0;
 wlv.filler_lines = diff_check_with_linestatus(wp, lnum, &linestatus);
 diffline_T line_changes = { 0 };
 int change_index = -1;
 if (linestatus < 0) {
   if (linestatus == -1) {
     if (diff_find_change(wp, lnum, &line_changes)) {
       wlv.diff_hlf = HLF_ADD;      // added line
     } else if (line_changes.num_changes > 0) {
       bool added = diff_change_parse(&line_changes, &line_changes.changes[0],
                                      &change_start, &change_end);
       if (change_start == 0) {
         if (added) {
           wlv.diff_hlf = HLF_TXA;  // added text on changed line
         } else {
           wlv.diff_hlf = HLF_TXD;  // changed text on changed line
         }
       } else {
         wlv.diff_hlf = HLF_CHD;    // unchanged text on changed line
       }
       change_index = 0;
     } else {
       wlv.diff_hlf = HLF_CHD;      // changed line
       change_index = 0;
     }
   } else {
     wlv.diff_hlf = HLF_ADD;               // added line
   }
   area_highlighting = true;
 }
 VirtLines virt_lines = KV_INITIAL_VALUE;
 wlv.n_virt_lines = decor_virt_lines(wp, lnum - 1, lnum, &wlv.n_virt_below, &virt_lines, true);
 wlv.filler_lines += wlv.n_virt_lines;
 if (lnum == wp->w_topline) {
   wlv.filler_lines = wp->w_topfill;
   wlv.n_virt_lines = MIN(wlv.n_virt_lines, wlv.filler_lines);
 }
 wlv.filler_todo = wlv.filler_lines;

 // Cursor line highlighting for 'cursorline' in the current window.
 if (wp->w_p_cul && wp->w_p_culopt_flags != kOptCuloptFlagNumber && lnum == wp->w_cursorline
     // Do not show the cursor line in the text when Visual mode is active,
     // because it's not clear what is selected then.
     && !(wp == curwin && VIsual_active)) {
   cul_screenline = (is_wrapped && (wp->w_p_culopt_flags & kOptCuloptFlagScreenline));
   if (!cul_screenline) {
     apply_cursorline_highlight(wp, &wlv);
   } else {
     margin_columns_win(wp, &left_curline_col, &right_curline_col);
   }
   area_highlighting = true;
 }

 int sign_line_attr = 0;
 // TODO(bfredl, vigoux): line_attr should not take priority over decoration!
 decor_redraw_signs(wp, buf, wlv.lnum - 1, wlv.sattrs,
                    &sign_line_attr, &wlv.sign_cul_attr, &wlv.sign_num_attr);

 statuscol_T statuscol = { 0 };
 if (*wp->w_p_stc != NUL) {
   // Draw the 'statuscolumn' if option is set.
   statuscol.draw = true;
   statuscol.sattrs = wlv.sattrs;
   statuscol.foldinfo = foldinfo;
   statuscol.width = win_col_off(wp) - (wp == cmdwin_win);
   statuscol.sign_cul_id = use_cursor_line_highlight(wp, lnum) ? wlv.sign_cul_attr : 0;
 } else if (wlv.sign_cul_attr > 0) {
   wlv.sign_cul_attr = use_cursor_line_highlight(wp, lnum) ? syn_id2attr(wlv.sign_cul_attr) : 0;
 }
 if (wlv.sign_num_attr > 0) {
   wlv.sign_num_attr = syn_id2attr(wlv.sign_num_attr);
 }
 if (sign_line_attr > 0) {
   wlv.line_attr = syn_id2attr(sign_line_attr);
 }

 // Highlight the current line in the quickfix window.
 if (bt_quickfix(wp->w_buffer) && qf_current_entry(wp) == lnum) {
   wlv.line_attr = win_hl_attr(wp, HLF_QFL);
 }

 if (wlv.line_attr_lowprio || wlv.line_attr) {
   area_highlighting = true;
 }

 int line_attr_save = wlv.line_attr;
 int line_attr_lowprio_save = wlv.line_attr_lowprio;

 if (spv->spv_has_spell && col_rows == 0 && draw_text) {
   // Prepare for spell checking.
   extra_check = true;

   // When a word wrapped from the previous line the start of the
   // current line is valid.
   if (lnum == spv->spv_checked_lnum) {
     cur_checked_col = spv->spv_checked_col;
   }
   // Previous line was not spell checked, check for capital. This happens
   // for the first line in an updated region or after a closed fold.
   if (spv->spv_capcol_lnum == 0 && check_need_cap(wp, lnum, 0)) {
     spv->spv_cap_col = 0;
   } else if (lnum != spv->spv_capcol_lnum) {
     spv->spv_cap_col = -1;
   }
   spv->spv_checked_lnum = 0;

   // Get the start of the next line, so that words that wrap to the
   // next line are found too: "et<line-break>al.".
   // Trick: skip a few chars for C/shell/Vim comments
   nextline[SPWORDLEN] = NUL;
   if (lnum < wp->w_buffer->b_ml.ml_line_count) {
     char *line = ml_get_buf(wp->w_buffer, lnum + 1);
     spell_cat_line(nextline + SPWORDLEN, line, SPWORDLEN);
   }
   char *line = ml_get_buf(wp->w_buffer, lnum);

   // If current line is empty, check first word in next line for capital.
   char *ptr = skipwhite(line);
   if (*ptr == NUL) {
     spv->spv_cap_col = 0;
     spv->spv_capcol_lnum = lnum + 1;
   } else if (spv->spv_cap_col == 0) {
     // For checking first word with a capital skip white space.
     spv->spv_cap_col = (int)(ptr - line);
   }

   // Copy the end of the current line into nextline[].
   if (nextline[SPWORDLEN] == NUL) {
     // No next line or it is empty.
     nextlinecol = MAXCOL;
     nextline_idx = 0;
   } else {
     const colnr_T line_len = ml_get_buf_len(wp->w_buffer, lnum);
     if (line_len < SPWORDLEN) {
       // Short line, use it completely and append the start of the
       // next line.
       nextlinecol = 0;
       memmove(nextline, line, (size_t)line_len);
       STRMOVE(nextline + line_len, nextline + SPWORDLEN);
       nextline_idx = line_len + 1;
     } else {
       // Long line, use only the last SPWORDLEN bytes.
       nextlinecol = line_len - SPWORDLEN;
       memmove(nextline, line + nextlinecol, SPWORDLEN);
       nextline_idx = SPWORDLEN + 1;
     }
   }
 }

 // current line
 char *line = draw_text ? ml_get_buf(wp->w_buffer, lnum) : "";
 // current position in "line"
 char *ptr = line;

 colnr_T trailcol = MAXCOL;  // start of trailing spaces
 colnr_T leadcol = 0;        // start of leading spaces

 bool lcs_eol_todo = true;  // need to keep track of this even if lcs_eol is NUL
 const schar_T lcs_eol = wp->w_p_lcs_chars.eol;  // 'eol' value
 schar_T lcs_prec_todo = wp->w_p_lcs_chars.prec;  // 'prec' until it's been used, then NUL

 if (wp->w_p_list && !has_foldtext && draw_text) {
   if (wp->w_p_lcs_chars.space
       || wp->w_p_lcs_chars.multispace != NULL
       || wp->w_p_lcs_chars.leadmultispace != NULL
       || wp->w_p_lcs_chars.trail
       || wp->w_p_lcs_chars.lead
       || wp->w_p_lcs_chars.nbsp) {
     extra_check = true;
   }
   // find start of trailing whitespace
   if (wp->w_p_lcs_chars.trail) {
     trailcol = ml_get_buf_len(wp->w_buffer, lnum);
     while (trailcol > 0 && ascii_iswhite(ptr[trailcol - 1])) {
       trailcol--;
     }
     trailcol += (colnr_T)(ptr - line);
   }
   // find end of leading whitespace
   if (wp->w_p_lcs_chars.lead || wp->w_p_lcs_chars.leadmultispace != NULL
       || wp->w_p_lcs_chars.leadtab1 != NUL) {
     leadcol = 0;
     while (ascii_iswhite(ptr[leadcol])) {
       leadcol++;
     }
     if (ptr[leadcol] == NUL) {
       // in a line full of spaces all of them are treated as trailing
       leadcol = 0;
     } else {
       // keep track of the first column not filled with spaces
       leadcol += (colnr_T)(ptr - line + 1);
     }
   }
 }

 // 'nowrap' or 'wrap' and a single line that doesn't fit: Advance to the
 // first character to be displayed.
 const int start_vcol = wp->w_p_wrap
                        ? (startrow == 0 ? wp->w_skipcol : 0)
                        : wp->w_leftcol;

 if (has_foldtext) {
   wlv.vcol = start_vcol;
 } else if (start_vcol > 0 && col_rows == 0) {
   char *prev_ptr = ptr;
   CharSize cs = { 0 };

   CharsizeArg csarg;
   CSType cstype = init_charsize_arg(&csarg, wp, lnum, line);
   csarg.max_head_vcol = start_vcol;
   int vcol = wlv.vcol;
   StrCharInfo ci = utf_ptr2StrCharInfo(ptr);
   while (vcol < start_vcol) {
     cs = win_charsize(cstype, vcol, ci.ptr, ci.chr.value, &csarg);
     vcol += cs.width;
     prev_ptr = ci.ptr;
     if (*prev_ptr == NUL) {
       break;
     }
     ci = utfc_next(ci);
     if (wp->w_p_list) {
       in_multispace = *prev_ptr == ' ' && (*ci.ptr == ' '
                                            || (prev_ptr > line && prev_ptr[-1] == ' '));
       if (!in_multispace) {
         multispace_pos = 0;
       } else if (ci.ptr >= line + leadcol
                  && wp->w_p_lcs_chars.multispace != NULL) {
         multispace_pos++;
         if (wp->w_p_lcs_chars.multispace[multispace_pos] == NUL) {
           multispace_pos = 0;
         }
       } else if (ci.ptr < line + leadcol
                  && wp->w_p_lcs_chars.leadmultispace != NULL) {
         multispace_pos++;
         if (wp->w_p_lcs_chars.leadmultispace[multispace_pos] == NUL) {
           multispace_pos = 0;
         }
       }
     }
   }
   wlv.vcol = vcol;
   ptr = ci.ptr;
   int charsize = cs.width;
   int head = cs.head;

   // When:
   // - 'cuc' is set, or
   // - 'colorcolumn' is set, or
   // - 'virtualedit' is set, or
   // - the visual mode is active, or
   // - drawing a fold
   // the end of the line may be before the start of the displayed part.
   if (wlv.vcol < start_vcol && (wp->w_p_cuc
                                 || wlv.color_cols
                                 || virtual_active(wp)
                                 || (VIsual_active && wp->w_buffer == curwin->w_buffer)
                                 || has_fold)) {
     wlv.vcol = start_vcol;
   }

   // Handle a character that's not completely on the screen: Put ptr at
   // that character but skip the first few screen characters.
   if (wlv.vcol > start_vcol) {
     wlv.vcol -= charsize;
     ptr = prev_ptr;
   }

   if (start_vcol > wlv.vcol) {
     wlv.skip_cells = start_vcol - wlv.vcol - head;
   }

   // Adjust for when the inverted text is before the screen,
   // and when the start of the inverted text is before the screen.
   if (wlv.tocol <= wlv.vcol) {
     wlv.fromcol = 0;
   } else if (wlv.fromcol >= 0 && wlv.fromcol < wlv.vcol) {
     wlv.fromcol = wlv.vcol;
   }

   // When w_skipcol is non-zero, first line needs 'showbreak'
   if (wp->w_p_wrap) {
     wlv.need_showbreak = true;
   }
   // When spell checking a word we need to figure out the start of the
   // word and if it's badly spelled or not.
   if (spv->spv_has_spell) {
     colnr_T linecol = (colnr_T)(ptr - line);
     hlf_T spell_hlf = HLF_COUNT;

     pos_T pos = wp->w_cursor;
     wp->w_cursor.lnum = lnum;
     wp->w_cursor.col = linecol;
     size_t len = spell_move_to(wp, FORWARD, SMT_ALL, true, &spell_hlf);

     // spell_move_to() may call ml_get() and make "line" invalid
     line = ml_get_buf(wp->w_buffer, lnum);
     ptr = line + linecol;

     if (len == 0 || wp->w_cursor.col > linecol) {
       // no bad word found at line start, don't check until end of a
       // word
       spell_hlf = HLF_COUNT;
       word_end = (int)(spell_to_word_end(ptr, wp) - line + 1);
     } else {
       // bad word found, use attributes until end of word
       assert(len <= INT_MAX);
       word_end = wp->w_cursor.col + (int)len + 1;

       // Turn index into actual attributes.
       if (spell_hlf != HLF_COUNT) {
         spell_attr = highlight_attr[spell_hlf];
       }
     }
     wp->w_cursor = pos;

     // Need to restart syntax highlighting for this line.
     if (has_syntax) {
       syntax_start(wp, lnum);
     }
   }
 }

 if (check_decor_providers) {
   int const col = (int)(ptr - line);
   decor_provider_end_col = decor_providers_setup(endrow - startrow,
                                                  start_vcol == 0,
                                                  lnum,
                                                  col,
                                                  wp);
   line = ml_get_buf(wp->w_buffer, lnum);
   ptr = line + col;
 }

 decor_redraw_line(wp, lnum - 1, &decor_state);
 if (!has_decor && decor_has_more_decorations(&decor_state, lnum - 1)) {
   has_decor = true;
   extra_check = true;
 }

 // Correct highlighting for cursor that can't be disabled.
 // Avoids having to check this for each character.
 if (wlv.fromcol >= 0) {
   if (noinvcur) {
     if ((colnr_T)wlv.fromcol == wp->w_virtcol) {
       // highlighting starts at cursor, let it start just after the
       // cursor
       fromcol_prev = wlv.fromcol;
       wlv.fromcol = -1;
     } else if ((colnr_T)wlv.fromcol < wp->w_virtcol) {
       // restart highlighting after the cursor
       fromcol_prev = wp->w_virtcol;
     }
   }
   if (wlv.fromcol >= wlv.tocol) {
     wlv.fromcol = -1;
   }
 }

 if (col_rows == 0 && draw_text && !has_foldtext) {
   const int v = (int)(ptr - line);
   area_highlighting |= prepare_search_hl_line(wp, lnum, v,
                                               &line, &screen_search_hl, &search_attr,
                                               &search_attr_from_match);
   ptr = line + v;  // "line" may have been updated
 }

 if ((State & MODE_INSERT) && ins_compl_win_active(wp)
     && (in_curline || ins_compl_lnum_in_range(lnum))) {
   area_highlighting = true;
 }

 win_line_start(wp, &wlv);
 bool draw_cols = true;
 int leftcols_width = 0;

 // won't highlight after TERM_ATTRS_MAX columns
 int term_attrs[TERM_ATTRS_MAX] = { 0 };
 if (wp->w_buffer->terminal) {
   terminal_get_line_attributes(wp->w_buffer->terminal, wp, lnum, term_attrs);
   extra_check = true;
 }

 const bool may_have_inline_virt
   = !has_foldtext && buf_meta_total(wp->w_buffer, kMTMetaInline) > 0;
 int virt_line_index = -1;
 int virt_line_flags = 0;

 // Repeat for each cell in the displayed line.
 while (true) {
   int has_match_conc = 0;  ///< match wants to conceal
   int decor_conceal = 0;

   bool did_decrement_ptr = false;

   // Get next chunk of extmark highlights if previous approximation was smaller than needed.
   if (check_decor_providers && (int)(ptr - line) >= decor_provider_end_col) {
     int const col = (int)(ptr - line);
     decor_provider_end_col = invoke_range_next(wp, lnum, col, 100);
     line = ml_get_buf(wp->w_buffer, lnum);
     ptr = line + col;
     if (!has_decor && decor_has_more_decorations(&decor_state, lnum - 1)) {
       has_decor = true;
       extra_check = true;
     }
   }

   // Skip this quickly when working on the text.
   if (draw_cols) {
     if (cul_screenline) {
       wlv.cul_attr = 0;
       wlv.line_attr = line_attr_save;
       wlv.line_attr_lowprio = line_attr_lowprio_save;
     }

     assert(wlv.off == 0);

     if (wp == cmdwin_win) {
       // Draw the cmdline character.
       draw_col_fill(&wlv, schar_from_ascii(cmdwin_type), 1, win_hl_attr(wp, HLF_AT));
     }

     if (wlv.filler_todo > 0) {
       int index = wlv.filler_todo - (wlv.filler_lines - wlv.n_virt_lines);
       if (index > 0) {
         virt_line_index = (int)kv_size(virt_lines) - index;
         assert(virt_line_index >= 0);
         virt_line_flags = kv_A(virt_lines, virt_line_index).flags;
       }
     }

     if (virt_line_index >= 0 && (virt_line_flags & kVLLeftcol)) {
       // skip columns
     } else if (statuscol.draw) {
       // Draw 'statuscolumn' if it is set.
       const int v = (int)(ptr - line);
       draw_statuscol(wp, &wlv, wlv.row - startrow - wlv.filler_lines, col_rows, &statuscol);
       if (wp->w_redr_statuscol) {
         break;
       }
       if (draw_text) {
         // Get the line again as evaluating 'statuscolumn' may free it.
         line = ml_get_buf(wp->w_buffer, lnum);
         ptr = line + v;
       }
     } else {
       // draw builtin info columns: fold, sign, number
       draw_foldcolumn(wp, &wlv);

       // wp->w_scwidth is zero if signcol=number is used
       for (int sign_idx = 0; sign_idx < wp->w_scwidth; sign_idx++) {
         draw_sign(false, wp, &wlv, sign_idx);
       }

       draw_lnum_col(wp, &wlv);
     }

     win_col_offset = wlv.off;

     // When only updating the columns and that's done, stop here.
     if (col_rows > 0) {
       wlv_put_linebuf(wp, &wlv, MIN(wlv.off, view_width), false, bg_attr, 0);
       // Need to update more screen lines if:
       // - 'statuscolumn' needs to be drawn, or
       // - LineNrAbove or LineNrBelow is used, or
       // - still drawing filler lines.
       if ((wlv.row + 1 - wlv.startrow < col_rows
            && (statuscol.draw
                || win_hl_attr(wp, HLF_LNA) != win_hl_attr(wp, HLF_N)
                || win_hl_attr(wp, HLF_LNB) != win_hl_attr(wp, HLF_N)))
           || wlv.filler_todo > 0) {
         wlv.row++;
         if (wlv.row == endrow) {
           break;
         }
         wlv.filler_todo--;
         virt_line_index = -1;
         if (wlv.filler_todo == 0 && (wp->w_botfill || !draw_text)) {
           break;
         }
         // win_line_start(wp, &wlv);
         wlv.col = 0;
         wlv.off = 0;
         continue;
       } else {
         break;
       }
     }

     // Check if 'breakindent' applies and show it.
     if (!wp->w_briopt_sbr) {
       handle_breakindent(wp, &wlv);
     }
     handle_showbreak_and_filler(wp, &wlv);
     if (wp->w_briopt_sbr) {
       handle_breakindent(wp, &wlv);
     }

     wlv.col = wlv.off;
     draw_cols = false;
     if (wlv.filler_todo <= 0) {
       leftcols_width = wlv.off;
     }
     if (has_decor && wlv.row == startrow + wlv.filler_lines) {
       // hide virt_text on text hidden by 'nowrap' or 'smoothscroll'
       decor_redraw_col(wp, (colnr_T)(ptr - line) - 1, wlv.off, true, &decor_state);
     }
     if (wlv.col >= view_width) {
       wlv.col = wlv.off = view_width;
       goto end_check;
     }
   }

   if (cul_screenline && wlv.filler_todo <= 0
       && wlv.vcol >= left_curline_col && wlv.vcol < right_curline_col) {
     apply_cursorline_highlight(wp, &wlv);
   }

   // When still displaying '$' of change command, stop at cursor.
   if (dollar_vcol >= 0 && in_curline && wlv.vcol >= wp->w_virtcol) {
     draw_virt_text(wp, buf, win_col_offset, &wlv.col, wlv.row);
     // don't clear anything after wlv.col
     wlv_put_linebuf(wp, &wlv, wlv.col, false, bg_attr, 0);
     // Pretend we have finished updating the window.  Except when
     // 'cursorcolumn' is set.
     if (wp->w_p_cuc) {
       wlv.row = wp->w_cline_row + wp->w_cline_height;
     } else {
       wlv.row = view_height;
     }
     break;
   }

   const bool draw_folded = has_fold && wlv.row == startrow + wlv.filler_lines;
   if (draw_folded && wlv.n_extra == 0) {
     wlv.char_attr = folded_attr = win_hl_attr(wp, HLF_FL);
     decor_attr = 0;
   }

   int extmark_attr = 0;
   if (wlv.filler_todo <= 0
       && (area_highlighting || spv->spv_has_spell || extra_check)) {
     if (wlv.n_extra == 0 || !wlv.extra_for_extmark) {
       wlv.reset_extra_attr = false;
     }

     if (has_decor && wlv.n_extra == 0) {
       // Duplicate the Visual area check after this block,
       // but don't check inside p_extra here.
       if (wlv.vcol == wlv.fromcol
           || (wlv.vcol + 1 == wlv.fromcol
               && (wlv.n_extra == 0 && utf_ptr2cells(ptr) > 1))
           || (vcol_prev == fromcol_prev
               && vcol_prev < wlv.vcol
               && wlv.vcol < wlv.tocol)) {
         area_active = true;
       } else if (area_active
                  && (wlv.vcol == wlv.tocol
                      || (noinvcur && wlv.vcol == wp->w_virtcol))) {
         area_active = false;
       }

       bool selected = (area_active || (area_highlighting && noinvcur
                                        && wlv.vcol == wp->w_virtcol));
       // When there may be inline virtual text, position of non-inline virtual text
       // can only be decided after drawing inline virtual text with lower priority.
       if (decor_need_recheck) {
         if (!may_have_inline_virt) {
           decor_recheck_draw_col(wlv.off, selected, &decor_state);
         }
         decor_need_recheck = false;
       }
       extmark_attr = decor_redraw_col(wp, (colnr_T)(ptr - line),
                                       may_have_inline_virt ? -3 : wlv.off,
                                       selected, &decor_state);
       if (may_have_inline_virt) {
         handle_inline_virtual_text(wp, &wlv, ptr - line, selected);
         if (wlv.n_extra > 0 && wlv.virt_inline_hl_mode <= kHlModeReplace) {
           // restore search_attr and area_attr when n_extra is down to zero
           // TODO(bfredl): this is ugly as fuck. look if we can do this some other way.
           saved_search_attr = search_attr;
           saved_area_attr = area_attr;
           saved_decor_attr = decor_attr;
           saved_search_attr_from_match = search_attr_from_match;
           search_attr = 0;
           area_attr = 0;
           decor_attr = 0;
           search_attr_from_match = false;
         }
       }
     }

     int *area_attr_p = wlv.extra_for_extmark && wlv.virt_inline_hl_mode <= kHlModeReplace
                        ? &saved_area_attr : &area_attr;

     // handle Visual or match highlighting in this line
     if (wlv.vcol == wlv.fromcol
         || (wlv.vcol + 1 == wlv.fromcol
             && ((wlv.n_extra == 0 && utf_ptr2cells(ptr) > 1)
                 || (wlv.n_extra > 0 && wlv.p_extra != NULL
                     && utf_ptr2cells(wlv.p_extra) > 1)))
         || (vcol_prev == fromcol_prev
             && vcol_prev < wlv.vcol               // not at margin
             && wlv.vcol < wlv.tocol)) {
       *area_attr_p = vi_attr;                     // start highlighting
       area_active = true;
     } else if (*area_attr_p != 0
                && (wlv.vcol == wlv.tocol
                    || (noinvcur && wlv.vcol == wp->w_virtcol))) {
       *area_attr_p = 0;                           // stop highlighting
       area_active = false;
     }

     if (!has_foldtext && wlv.n_extra == 0) {
       // Check for start/end of 'hlsearch' and other matches.
       // After end, check for start/end of next match.
       // When another match, have to check for start again.
       const int v = (int)(ptr - line);
       search_attr = update_search_hl(wp, lnum, v, &line, &screen_search_hl,
                                      &has_match_conc, &match_conc, lcs_eol_todo,
                                      &on_last_col, &search_attr_from_match);
       ptr = line + v;  // "line" may have been changed

       // Do not allow a conceal over EOL otherwise EOL will be missed
       // and bad things happen.
       if (*ptr == NUL) {
         has_match_conc = 0;
       }

       // Check if ComplMatchIns highlight is needed.
       if ((State & MODE_INSERT) && ins_compl_win_active(wp)
           && (in_curline || ins_compl_lnum_in_range(lnum))) {
         int ins_match_attr = ins_compl_col_range_attr(lnum, (int)(ptr - line));
         if (ins_match_attr > 0) {
           search_attr = hl_combine_attr(search_attr, ins_match_attr);
         }
       }
     }

     if (wlv.diff_hlf != (hlf_T)0) {
       if (line_changes.num_changes > 0
           && change_index >= 0
           && change_index < line_changes.num_changes - 1) {
         if (ptr - line
             >= line_changes.changes[change_index + 1].dc_start[line_changes.bufidx]) {
           change_index += 1;
         }
       }
       bool added = false;
       if (line_changes.num_changes > 0 && change_index >= 0
           && change_index < line_changes.num_changes) {
         added = diff_change_parse(&line_changes, &line_changes.changes[change_index],
                                   &change_start, &change_end);
       }
       // When there is extra text (eg: virtual text) it gets the
       // diff highlighting for the line, but not for changed text.
       if (wlv.diff_hlf == HLF_CHD && ptr - line >= change_start
           && wlv.n_extra == 0) {
         wlv.diff_hlf = added ? HLF_TXA : HLF_TXD;   // added/changed text
       }
       if ((wlv.diff_hlf == HLF_TXD || wlv.diff_hlf == HLF_TXA)
           && ((ptr - line >= change_end && wlv.n_extra == 0)
               || (wlv.n_extra > 0 && wlv.extra_for_extmark))) {
         wlv.diff_hlf = HLF_CHD;                     // changed line
       }
       set_line_attr_for_diff(wp, &wlv);
     }

     // Decide which of the highlight attributes to use.
     if (area_attr != 0) {
       char_attr_pri = hl_combine_attr(wlv.line_attr, area_attr);
       if (!highlight_match) {
         // let search highlight show in Visual area if possible
         char_attr_pri = hl_combine_attr(search_attr, char_attr_pri);
       }
     } else if (search_attr != 0) {
       char_attr_pri = hl_combine_attr(wlv.line_attr, search_attr);
     } else if (wlv.line_attr != 0
                && ((wlv.fromcol == -10 && wlv.tocol == MAXCOL)
                    || wlv.vcol < wlv.fromcol
                    || vcol_prev < fromcol_prev
                    || wlv.vcol >= wlv.tocol)) {
       // Use wlv.line_attr when not in the Visual or 'incsearch' area
       // (area_attr may be 0 when "noinvcur" is set).
       char_attr_pri = wlv.line_attr;
     } else {
       char_attr_pri = 0;
     }
     char_attr_base = hl_combine_attr(folded_attr, decor_attr);
     wlv.char_attr = hl_combine_attr(char_attr_base, char_attr_pri);
   }

   if (draw_folded && has_foldtext && wlv.n_extra == 0 && wlv.col == win_col_offset) {
     const int v = (int)(ptr - line);
     linenr_T lnume = lnum + foldinfo.fi_lines - 1;
     memset(buf_fold, ' ', FOLD_TEXT_LEN);
     wlv.p_extra = get_foldtext(wp, lnum, lnume, foldinfo, buf_fold, &fold_vt);
     wlv.n_extra = (int)strlen(wlv.p_extra);

     if (wlv.p_extra != buf_fold) {
       assert(foldtext_free == NULL);
       foldtext_free = wlv.p_extra;
     }
     wlv.sc_extra = NUL;
     wlv.sc_final = NUL;
     wlv.p_extra[wlv.n_extra] = NUL;

     // Get the line again as evaluating 'foldtext' may free it.
     line = ml_get_buf(wp->w_buffer, lnum);
     ptr = line + v;
   }

   // Draw 'fold' fillchar after 'foldtext', or after 'eol' listchar for transparent 'foldtext'.
   if (draw_folded && wlv.n_extra == 0 && wlv.col < view_width
       && (has_foldtext || (*ptr == NUL && (!wp->w_p_list || !lcs_eol_todo || lcs_eol == NUL)))) {
     // Fill rest of line with 'fold'.
     wlv.sc_extra = wp->w_p_fcs_chars.fold;
     wlv.sc_final = NUL;
     wlv.n_extra = view_width - wlv.col;
     // Don't continue search highlighting past the first filler char.
     search_attr = 0;
   }

   if (draw_folded && wlv.n_extra != 0 && wlv.col >= view_width) {
     // Truncate the folding.
     wlv.n_extra = 0;
   }

   // Get the next character to put on the screen.
   //
   // The "p_extra" points to the extra stuff that is inserted to
   // represent special characters (non-printable stuff) and other
   // things.  When all characters are the same, sc_extra is used.
   // If sc_final is set, it will compulsorily be used at the end.
   // "p_extra" must end in a NUL to avoid utfc_ptr2len() reads past
   // "p_extra[n_extra]".
   // For the '$' of the 'list' option, n_extra == 1, p_extra == "".
   if (wlv.n_extra > 0) {
     if (wlv.sc_extra != NUL || (wlv.n_extra == 1 && wlv.sc_final != NUL)) {
       mb_schar = (wlv.n_extra == 1 && wlv.sc_final != NUL) ? wlv.sc_final : wlv.sc_extra;
       mb_c = schar_get_first_codepoint(mb_schar);
       wlv.n_extra--;
     } else {
       assert(wlv.p_extra != NULL);
       mb_l = utfc_ptr2len(wlv.p_extra);
       mb_schar = utfc_ptr2schar(wlv.p_extra, &mb_c);
       // mb_l=0 at the end-of-line NUL
       if (mb_l > wlv.n_extra || mb_l == 0) {
         mb_l = 1;
       }

       // If a double-width char doesn't fit display a '>' in the last column.
       // Don't advance the pointer but put the character at the start of the next line.
       if (wlv.col >= view_width - 1 && schar_cells(mb_schar) == 2) {
         mb_c = '>';
         mb_l = 1;
         mb_schar = schar_from_ascii(mb_c);
         multi_attr = win_hl_attr(wp, HLF_AT);

         if (wlv.cul_attr) {
           multi_attr = 0 != wlv.line_attr_lowprio
                        ? hl_combine_attr(wlv.cul_attr, multi_attr)
                        : hl_combine_attr(multi_attr, wlv.cul_attr);
         }
       } else {
         wlv.n_extra -= mb_l;
         wlv.p_extra += mb_l;
       }

       // If a double-width char doesn't fit at the left side display a '<'.
       if (wlv.filler_todo <= 0 && wlv.skip_cells > 0 && mb_l > 1) {
         if (wlv.n_extra > 0) {
           n_extra_next = wlv.n_extra;
           extra_attr_next = wlv.extra_attr;
         }
         wlv.n_extra = 1;
         wlv.sc_extra = schar_from_ascii(MB_FILLER_CHAR);
         wlv.sc_final = NUL;
         mb_schar = schar_from_ascii(' ');
         mb_c = ' ';
         mb_l = 1;
         (void)mb_l;
         wlv.n_attr++;
         wlv.extra_attr = win_hl_attr(wp, HLF_AT);
       }
     }

     if (wlv.n_extra <= 0) {
       // Only restore search_attr and area_attr when there is no "n_extra" to show.
       if (n_extra_next <= 0) {
         if (search_attr == 0) {
           search_attr = saved_search_attr;
           saved_search_attr = 0;
         }
         if (area_attr == 0 && *ptr != NUL) {
           area_attr = saved_area_attr;
           saved_area_attr = 0;
         }
         if (decor_attr == 0) {
           decor_attr = saved_decor_attr;
           saved_decor_attr = 0;
         }
         if (wlv.extra_for_extmark) {
           // wlv.extra_attr should be used at this position but not any further.
           wlv.reset_extra_attr = true;
           extra_attr_next = -1;
         }
         wlv.extra_for_extmark = false;
       } else {
         assert(wlv.sc_extra != NUL || wlv.sc_final != NUL);
         assert(wlv.p_extra != NULL);
         wlv.sc_extra = NUL;
         wlv.sc_final = NUL;
         wlv.n_extra = n_extra_next;
         n_extra_next = 0;
         // wlv.extra_attr should be used at this position, but extra_attr_next
         // should be used after that.
         wlv.reset_extra_attr = true;
         assert(extra_attr_next >= 0);
       }
     }
   } else if (wlv.filler_todo > 0) {
     // Wait with reading text until filler lines are done. Still need to
     // initialize these.
     mb_c = ' ';
     mb_schar = schar_from_ascii(' ');
   } else if (has_foldtext || (has_fold && wlv.col >= view_width)) {
     // skip writing the buffer line itself
     mb_schar = NUL;
   } else {
     const char *prev_ptr = ptr;

     // first byte of next char
     int c0 = (uint8_t)(*ptr);
     if (c0 == NUL) {
       // no more cells to skip
       wlv.skip_cells = 0;
     }

     // Get a character from the line itself.
     mb_l = utfc_ptr2len(ptr);
     mb_schar = utfc_ptr2schar(ptr, &mb_c);

     // Overlong encoded ASCII or ASCII with composing char
     // is displayed normally, except a NUL.
     if (mb_l > 1 && mb_c < 0x80) {
       c0 = mb_c;
     }

     if ((mb_l == 1 && c0 >= 0x80)
         || (mb_l >= 1 && mb_c == 0)
         || (mb_l > 1 && (!vim_isprintc(mb_c)))) {
       // Illegal UTF-8 byte: display as <xx>.
       // Non-printable character : display as ? or fullwidth ?.
       transchar_hex(wlv.extra, mb_c);
       if (wp->w_p_rl) {  // reverse
         rl_mirror_ascii(wlv.extra, NULL);
       }

       wlv.p_extra = wlv.extra;
       mb_c = mb_ptr2char_adv((const char **)&wlv.p_extra);
       mb_schar = schar_from_char(mb_c);
       wlv.n_extra = (int)strlen(wlv.p_extra);
       wlv.sc_extra = NUL;
       wlv.sc_final = NUL;
       if (area_attr == 0 && search_attr == 0) {
         wlv.n_attr = wlv.n_extra + 1;
         wlv.extra_attr = win_hl_attr(wp, HLF_8);
         saved_attr2 = wlv.char_attr;               // save current attr
       }
     } else if (mb_l == 0) {        // at the NUL at end-of-line
       mb_l = 1;
     }
     // If a double-width char doesn't fit display a '>' in the
     // last column; the character is displayed at the start of the
     // next line.
     if (wlv.col >= view_width - 1 && schar_cells(mb_schar) == 2) {
       mb_schar = schar_from_ascii('>');
       mb_c = '>';
       mb_l = 1;
       multi_attr = win_hl_attr(wp, HLF_AT);
       // Put pointer back so that the character will be
       // displayed at the start of the next line.
       ptr--;
       did_decrement_ptr = true;
     } else if (*ptr != NUL) {
       ptr += mb_l - 1;
     }

     // If a double-width char doesn't fit at the left side display a '<' in
     // the first column.  Don't do this for unprintable characters.
     if (wlv.skip_cells > 0 && mb_l > 1 && wlv.n_extra == 0) {
       wlv.n_extra = 1;
       wlv.sc_extra = schar_from_ascii(MB_FILLER_CHAR);
       wlv.sc_final = NUL;
       mb_schar = schar_from_ascii(' ');
       mb_c = ' ';
       mb_l = 1;
       if (area_attr == 0 && search_attr == 0) {
         wlv.n_attr = wlv.n_extra + 1;
         wlv.extra_attr = win_hl_attr(wp, HLF_AT);
         saved_attr2 = wlv.char_attr;             // save current attr
       }
     }
     ptr++;

     decor_attr = 0;
     if (extra_check) {
       const bool no_plain_buffer = (wp->w_s->b_p_spo_flags & kOptSpoFlagNoplainbuffer) != 0;
       bool can_spell = !no_plain_buffer;

       // Get extmark and syntax attributes, unless still at the start of the line
       // (double-wide char that doesn't fit).
       const int v = (int)(ptr - line);
       const ptrdiff_t prev_v = prev_ptr - line;
       if (has_syntax && v > 0) {
         // Get the syntax attribute for the character.  If there
         // is an error, disable syntax highlighting.
         int save_did_emsg = did_emsg;
         did_emsg = false;

         decor_attr = get_syntax_attr(v - 1, spv->spv_has_spell ? &can_spell : NULL, false);

         if (did_emsg) {
           wp->w_s->b_syn_error = true;
           has_syntax = false;
         } else {
           did_emsg = save_did_emsg;
         }

         if (wp->w_s->b_syn_slow) {
           has_syntax = false;
         }

         // Need to get the line again, a multi-line regexp may
         // have made it invalid.
         line = ml_get_buf(wp->w_buffer, lnum);
         ptr = line + v;
         prev_ptr = line + prev_v;

         // no concealing past the end of the line, it interferes
         // with line highlighting.
         syntax_flags = (mb_schar == 0) ? 0 : get_syntax_info(&syntax_seqnr);
       }

       if (has_decor && v > 0) {
         // extmarks take preceedence over syntax.c
         decor_attr = hl_combine_attr(decor_attr, extmark_attr);
         decor_conceal = decor_state.conceal;
         can_spell = TRISTATE_TO_BOOL(decor_state.spell, can_spell);
       }

       char_attr_base = hl_combine_attr(folded_attr, decor_attr);
       wlv.char_attr = hl_combine_attr(char_attr_base, char_attr_pri);

       // Check spelling (unless at the end of the line).
       // Only do this when there is no syntax highlighting, the
       // @Spell cluster is not used or the current syntax item
       // contains the @Spell cluster.
       int v1 = (int)(ptr - line);
       if (spv->spv_has_spell && v1 >= word_end && v1 > cur_checked_col) {
         spell_attr = 0;
         // do not calculate cap_col at the end of the line or when
         // only white space is following
         if (mb_schar != 0 && (*skipwhite(prev_ptr) != NUL) && can_spell) {
           char *p;
           hlf_T spell_hlf = HLF_COUNT;
           v1 -= mb_l - 1;

           // Use nextline[] if possible, it has the start of the
           // next line concatenated.
           if ((prev_ptr - line) - nextlinecol >= 0) {
             p = nextline + ((prev_ptr - line) - nextlinecol);
           } else {
             p = (char *)prev_ptr;
           }
           spv->spv_cap_col -= (int)(prev_ptr - line);
           size_t tmplen = spell_check(wp, p, &spell_hlf, &spv->spv_cap_col, spv->spv_unchanged);
           assert(tmplen <= INT_MAX);
           int len = (int)tmplen;
           word_end = v1 + len;

           // In Insert mode only highlight a word that
           // doesn't touch the cursor.
           if (spell_hlf != HLF_COUNT
               && (State & MODE_INSERT)
               && wp->w_cursor.lnum == lnum
               && wp->w_cursor.col >= (colnr_T)(prev_ptr - line)
               && wp->w_cursor.col < (colnr_T)word_end) {
             spell_hlf = HLF_COUNT;
             spell_redraw_lnum = lnum;
           }

           if (spell_hlf == HLF_COUNT && p != prev_ptr
               && (p - nextline) + len > nextline_idx) {
             // Remember that the good word continues at the
             // start of the next line.
             spv->spv_checked_lnum = lnum + 1;
             spv->spv_checked_col = (int)((p - nextline) + len - nextline_idx);
           }

           // Turn index into actual attributes.
           if (spell_hlf != HLF_COUNT) {
             spell_attr = highlight_attr[spell_hlf];
           }

           if (spv->spv_cap_col > 0) {
             if (p != prev_ptr && (p - nextline) + spv->spv_cap_col >= nextline_idx) {
               // Remember that the word in the next line
               // must start with a capital.
               spv->spv_capcol_lnum = lnum + 1;
               spv->spv_cap_col = (int)((p - nextline) + spv->spv_cap_col - nextline_idx);
             } else {
               // Compute the actual column.
               spv->spv_cap_col += (int)(prev_ptr - line);
             }
           }
         }
       }
       if (spell_attr != 0) {
         char_attr_base = hl_combine_attr(char_attr_base, spell_attr);
         wlv.char_attr = hl_combine_attr(char_attr_base, char_attr_pri);
       }

       if (wp->w_buffer->terminal) {
         wlv.char_attr = hl_combine_attr(wlv.vcol < TERM_ATTRS_MAX ? term_attrs[wlv.vcol] : 0,
                                         wlv.char_attr);
       }

       // we don't want linebreak to apply for lines that start with
       // leading spaces, followed by long letters (since it would add
       // a break at the beginning of a line and this might be unexpected)
       //
       // So only allow to linebreak, once we have found chars not in
       // 'breakat' in the line.
       if (wp->w_p_lbr && !wlv.need_lbr && mb_schar != NUL
           && !vim_isbreak((uint8_t)(*ptr))) {
         wlv.need_lbr = true;
       }
       // Found last space before word: check for line break.
       if (wp->w_p_lbr && c0 == mb_c && mb_c < 128 && wlv.need_lbr
           && vim_isbreak(mb_c) && !vim_isbreak((uint8_t)(*ptr))) {
         int mb_off = utf_head_off(line, ptr - 1);
         char *p = ptr - (mb_off + 1);

         CharsizeArg csarg;
         // lnum == 0, do not want virtual text to be counted here
         CSType cstype = init_charsize_arg(&csarg, wp, 0, line);
         wlv.n_extra = win_charsize(cstype, wlv.vcol, p, utf_ptr2CharInfo(p).value,
                                    &csarg).width - 1;

         if (on_last_col && mb_c != TAB) {
           // Do not continue search/match highlighting over the
           // line break, but for TABs the highlighting should
           // include the complete width of the character
           search_attr = 0;
         }

         if (mb_c == TAB && wlv.n_extra + wlv.col > view_width) {
           wlv.n_extra = tabstop_padding(wlv.vcol, wp->w_buffer->b_p_ts,
                                         wp->w_buffer->b_p_vts_array) - 1;
         }
         wlv.sc_extra = schar_from_ascii(mb_off > 0 ? MB_FILLER_CHAR : ' ');
         wlv.sc_final = NUL;
         if (mb_c < 128 && ascii_iswhite(mb_c)) {
           if (mb_c == TAB) {
             // See "Tab alignment" below.
             fix_for_boguscols(&wlv);
           }
           if (!wp->w_p_list) {
             mb_c = ' ';
             mb_schar = schar_from_ascii(mb_c);
           }
         }
       }

       if (wp->w_p_list) {
         in_multispace = mb_c == ' ' && (*ptr == ' ' || (prev_ptr > line && prev_ptr[-1] == ' '));
         if (!in_multispace) {
           multispace_pos = 0;
         }
       }

       // 'list': Change char 160 to 'nbsp' and space to 'space'.
       // But not when the character is followed by a composing
       // character (use mb_l to check that).
       if (wp->w_p_list
           && ((((mb_c == 160 && mb_l == 2) || (mb_c == 0x202f && mb_l == 3))
                && wp->w_p_lcs_chars.nbsp)
               || (mb_c == ' '
                   && mb_l == 1
                   && (wp->w_p_lcs_chars.space
                       || (in_multispace && wp->w_p_lcs_chars.multispace != NULL))
                   && ptr - line >= leadcol
                   && ptr - line <= trailcol))) {
         if (in_multispace && wp->w_p_lcs_chars.multispace != NULL) {
           mb_schar = wp->w_p_lcs_chars.multispace[multispace_pos++];
           if (wp->w_p_lcs_chars.multispace[multispace_pos] == NUL) {
             multispace_pos = 0;
           }
         } else {
           mb_schar = (mb_c == ' ') ? wp->w_p_lcs_chars.space : wp->w_p_lcs_chars.nbsp;
         }
         wlv.n_attr = 1;
         wlv.extra_attr = win_hl_attr(wp, HLF_0);
         saved_attr2 = wlv.char_attr;  // save current attr
         mb_c = schar_get_first_codepoint(mb_schar);
       }

       if (mb_c == ' ' && mb_l == 1 && ((trailcol != MAXCOL && ptr > line + trailcol)
                                        || (leadcol != 0 && ptr < line + leadcol))) {
         if (leadcol != 0 && in_multispace && ptr < line + leadcol
             && wp->w_p_lcs_chars.leadmultispace != NULL) {
           mb_schar = wp->w_p_lcs_chars.leadmultispace[multispace_pos++];
           if (wp->w_p_lcs_chars.leadmultispace[multispace_pos] == NUL) {
             multispace_pos = 0;
           }
         } else if (ptr > line + trailcol && wp->w_p_lcs_chars.trail) {
           mb_schar = wp->w_p_lcs_chars.trail;
         } else if (ptr < line + leadcol && wp->w_p_lcs_chars.lead) {
           mb_schar = wp->w_p_lcs_chars.lead;
         } else if (leadcol != 0 && wp->w_p_lcs_chars.space) {
           mb_schar = wp->w_p_lcs_chars.space;
         }

         wlv.n_attr = 1;
         wlv.extra_attr = win_hl_attr(wp, HLF_0);
         saved_attr2 = wlv.char_attr;  // save current attr
         mb_c = schar_get_first_codepoint(mb_schar);
       }
     }

     // Handling of non-printable characters.
     if (!vim_isprintc(mb_c)) {
       // when getting a character from the file, we may have to
       // turn it into something else on the way to putting it on the screen.
       if (mb_c == TAB && (!wp->w_p_list || wp->w_p_lcs_chars.tab1)) {
         int tab_len = 0;
         colnr_T vcol_adjusted = wlv.vcol;  // removed showbreak length
         schar_T lcs_tab1 = wp->w_p_lcs_chars.tab1;
         schar_T lcs_tab2 = wp->w_p_lcs_chars.tab2;
         schar_T lcs_tab3 = wp->w_p_lcs_chars.tab3;
         // check if leadtab is set in 'listchars'
         if (wp->w_p_list && wp->w_p_lcs_chars.leadtab1 != NUL
             && ptr < line + leadcol) {
           lcs_tab1 = wp->w_p_lcs_chars.leadtab1;
           lcs_tab2 = wp->w_p_lcs_chars.leadtab2;
           lcs_tab3 = wp->w_p_lcs_chars.leadtab3;
         }
         char *const sbr = get_showbreak_value(wp);

         // Only adjust the tab_len, when at the first column after the
         // showbreak value was drawn.
         if (*sbr != NUL && wlv.vcol == wlv.vcol_sbr && wp->w_p_wrap) {
           vcol_adjusted = wlv.vcol - mb_charlen(sbr);
         }
         // tab amount depends on current column
         tab_len = tabstop_padding(vcol_adjusted,
                                   wp->w_buffer->b_p_ts,
                                   wp->w_buffer->b_p_vts_array) - 1;

         if (!wp->w_p_lbr || !wp->w_p_list) {
           wlv.n_extra = tab_len;
         } else {
           int saved_nextra = wlv.n_extra;

           if (wlv.vcol_off_co > 0) {
             // there are characters to conceal
             tab_len += wlv.vcol_off_co;
           }
           // boguscols before fix_for_boguscols() from above.
           if (lcs_tab1 && wlv.old_boguscols > 0 && wlv.n_extra > tab_len) {
             tab_len += wlv.n_extra - tab_len;
           }

           if (tab_len > 0) {
             // If wlv.n_extra > 0, it gives the number of chars
             // to use for a tab, else we need to calculate the
             // width for a tab.
             size_t tab2_len = schar_len(lcs_tab2);
             size_t len = (size_t)tab_len * tab2_len;
             if (lcs_tab3) {
               len += schar_len(lcs_tab3) - tab2_len;
             }
             if (wlv.n_extra > 0) {
               len += (size_t)(wlv.n_extra - tab_len);
             }
             mb_schar = lcs_tab1;
             mb_c = schar_get_first_codepoint(mb_schar);
             char *p = get_extra_buf(len + 1);
             memset(p, ' ', len);
             p[len] = NUL;
             wlv.p_extra = p;
             for (int i = 0; i < tab_len; i++) {
               if (*p == NUL) {
                 tab_len = i;
                 break;
               }
               schar_T lcs = lcs_tab2;

               // if tab3 is given, use it for the last char
               if (lcs_tab3 && i == tab_len - 1) {
                 lcs = lcs_tab3;
               }
               size_t slen = schar_get_adv(&p, lcs);
               wlv.n_extra += (int)slen - (saved_nextra > 0 ? 1 : 0);
             }

             // n_extra will be increased by fix_for_boguscols()
             // below, so need to adjust for that here
             if (wlv.vcol_off_co > 0) {
               wlv.n_extra -= wlv.vcol_off_co;
             }
           }
         }

         {
           int vc_saved = wlv.vcol_off_co;

           // Tab alignment should be identical regardless of
           // 'conceallevel' value. So tab compensates of all
           // previous concealed characters, and thus resets
           // vcol_off_co and boguscols accumulated so far in the
           // line. Note that the tab can be longer than
           // 'tabstop' when there are concealed characters.
           fix_for_boguscols(&wlv);

           // Make sure, the highlighting for the tab char will be
           // correctly set further below (effectively reverts the
           // fix_for_boguscols() call).
           if (wlv.n_extra == tab_len + vc_saved && wp->w_p_list
               && wp->w_p_lcs_chars.tab1) {
             tab_len += vc_saved;
           }
         }

         if (wp->w_p_list) {
           mb_schar = (wlv.n_extra == 0 && lcs_tab3) ? lcs_tab3 : lcs_tab1;
           if (wp->w_p_lbr && wlv.p_extra != NULL && *wlv.p_extra != NUL) {
             wlv.sc_extra = NUL;  // using p_extra from above
           } else {
             wlv.sc_extra = lcs_tab2;
           }
           wlv.sc_final = lcs_tab3;
           wlv.n_attr = tab_len + 1;
           wlv.extra_attr = win_hl_attr(wp, HLF_0);
           saved_attr2 = wlv.char_attr;  // save current attr
         } else {
           wlv.sc_final = NUL;
           wlv.sc_extra = schar_from_ascii(' ');
           mb_schar = schar_from_ascii(' ');
         }
         mb_c = schar_get_first_codepoint(mb_schar);
       } else if (mb_schar == NUL
                  && (wp->w_p_list
                      || ((wlv.fromcol >= 0 || fromcol_prev >= 0)
                          && wlv.tocol > wlv.vcol
                          && VIsual_mode != Ctrl_V
                          && wlv.col < view_width
                          && !(noinvcur
                               && lnum == wp->w_cursor.lnum
                               && wlv.vcol == wp->w_virtcol)))
                  && lcs_eol_todo && lcs_eol != NUL) {
         // Display a '$' after the line or highlight an extra
         // character if the line break is included.
         // For a diff line the highlighting continues after the "$".
         if (wlv.diff_hlf == (hlf_T)0
             && wlv.line_attr == 0
             && wlv.line_attr_lowprio == 0) {
           // In virtualedit, visual selections may extend beyond end of line
           if (!(area_highlighting && virtual_active(wp)
                 && wlv.tocol != MAXCOL && wlv.vcol < wlv.tocol)) {
             wlv.p_extra = "";
           }
           wlv.n_extra = 0;
         }
         if (wp->w_p_list && wp->w_p_lcs_chars.eol > 0) {
           mb_schar = wp->w_p_lcs_chars.eol;
         } else {
           mb_schar = schar_from_ascii(' ');
         }
         lcs_eol_todo = false;
         ptr--;  // put it back at the NUL
         wlv.extra_attr = win_hl_attr(wp, HLF_AT);
         wlv.n_attr = 1;
         mb_c = schar_get_first_codepoint(mb_schar);
       } else if (mb_schar != NUL) {
         wlv.p_extra = transchar_buf(wp->w_buffer, mb_c);
         if (wlv.n_extra == 0) {
           wlv.n_extra = byte2cells(mb_c) - 1;
         }
         if ((dy_flags & kOptDyFlagUhex) && wp->w_p_rl) {
           rl_mirror_ascii(wlv.p_extra, NULL);   // reverse "<12>"
         }
         wlv.sc_extra = NUL;
         wlv.sc_final = NUL;
         if (wp->w_p_lbr) {
           mb_c = (uint8_t)(*wlv.p_extra);
           char *p = get_extra_buf((size_t)wlv.n_extra + 1);
           memset(p, ' ', (size_t)wlv.n_extra);
           memcpy(p, wlv.p_extra + 1, strlen(wlv.p_extra) - 1);
           p[wlv.n_extra] = NUL;
           wlv.p_extra = p;
         } else {
           wlv.n_extra = byte2cells(mb_c) - 1;
           mb_c = (uint8_t)(*wlv.p_extra++);
         }
         wlv.n_attr = wlv.n_extra + 1;
         wlv.extra_attr = win_hl_attr(wp, HLF_8);
         saved_attr2 = wlv.char_attr;  // save current attr
         mb_schar = schar_from_ascii(mb_c);
       } else if (VIsual_active
                  && (VIsual_mode == Ctrl_V || VIsual_mode == 'v')
                  && virtual_active(wp)
                  && wlv.tocol != MAXCOL
                  && wlv.vcol < wlv.tocol
                  && wlv.col < view_width) {
         mb_c = ' ';
         mb_schar = schar_from_char(mb_c);
         ptr--;  // put it back at the NUL
       }
     }

     if (wp->w_p_cole > 0
         && (wp != curwin || lnum != wp->w_cursor.lnum || conceal_cursor_line(wp))
         && ((syntax_flags & HL_CONCEAL) != 0 || has_match_conc > 0 || decor_conceal > 0)
         && !(lnum_in_visual_area && vim_strchr(wp->w_p_cocu, 'v') == NULL)) {
       bool syntax_conceal = (syntax_flags & HL_CONCEAL) != 0;
       wlv.char_attr = conceal_attr;
       if (((prev_syntax_id != syntax_seqnr && syntax_conceal)
            || has_match_conc > 1 || decor_conceal > 1)
           && ((syntax_conceal && syn_get_sub_char() != NUL)
               || (has_match_conc && match_conc)
               || (decor_conceal && decor_state.conceal_char)
               || wp->w_p_cole == 1)
           && wp->w_p_cole != 3) {
         if (schar_cells(mb_schar) > 1) {
           // When the first char to be concealed is double-width,
           // need to advance one more virtual column.
           wlv.n_extra++;
         }

         // First time at this concealed item: display one
         // character.
         if (has_match_conc && match_conc) {
           mb_schar = schar_from_char(match_conc);
         } else if (decor_conceal && decor_state.conceal_char) {
           mb_schar = decor_state.conceal_char;
           if (decor_state.conceal_attr) {
             wlv.char_attr = decor_state.conceal_attr;
           }
         } else if (syntax_conceal && syn_get_sub_char() != NUL) {
           mb_schar = schar_from_char(syn_get_sub_char());
         } else if (wp->w_p_lcs_chars.conceal != NUL) {
           mb_schar = wp->w_p_lcs_chars.conceal;
         } else {
           mb_schar = schar_from_ascii(' ');
         }

         mb_c = schar_get_first_codepoint(mb_schar);

         prev_syntax_id = syntax_seqnr;

         if (wlv.n_extra > 0) {
           wlv.vcol_off_co += wlv.n_extra;
         }
         wlv.vcol += wlv.n_extra;
         if (is_wrapped && wlv.n_extra > 0) {
           wlv.boguscols += wlv.n_extra;
           wlv.col += wlv.n_extra;
         }
         wlv.n_extra = 0;
         wlv.n_attr = 0;
       } else if (wlv.skip_cells == 0) {
         is_concealing = true;
         wlv.skip_cells = 1;
       }
     } else {
       prev_syntax_id = 0;
       is_concealing = false;
     }

     if (wlv.skip_cells > 0 && did_decrement_ptr) {
       // not showing the '>', put pointer back to avoid getting stuck
       ptr++;
     }
   }  // end of printing from buffer content

   // In the cursor line and we may be concealing characters: correct
   // the cursor column when we reach its position.
   // With 'virtualedit' we may never reach cursor position, but we still
   // need to correct the cursor column, so do that at end of line.
   if (!did_wcol && wlv.filler_todo <= 0
       && in_curline && conceal_cursor_line(wp)
       && (wlv.vcol + wlv.skip_cells >= wp->w_virtcol || mb_schar == NUL)) {
     wp->w_wcol = wlv.col - wlv.boguscols;
     if (wlv.vcol + wlv.skip_cells < wp->w_virtcol) {
       // Cursor beyond end of the line with 'virtualedit'.
       wp->w_wcol += wp->w_virtcol - wlv.vcol - wlv.skip_cells;
     }
     wp->w_wrow = wlv.row;
     did_wcol = true;
     wp->w_valid |= VALID_WCOL|VALID_WROW|VALID_VIRTCOL;
   }

   // Use "wlv.extra_attr", but don't override visual selection highlighting.
   if (wlv.n_attr > 0 && !search_attr_from_match) {
     wlv.char_attr = hl_combine_attr(wlv.char_attr, wlv.extra_attr);
     if (wlv.reset_extra_attr) {
       wlv.reset_extra_attr = false;
       if (extra_attr_next >= 0) {
         wlv.extra_attr = extra_attr_next;
         extra_attr_next = -1;
       } else {
         wlv.extra_attr = 0;
         // search_attr_from_match can be restored now that the extra_attr has been applied
         search_attr_from_match = saved_search_attr_from_match;
       }
     }
   }

   // Handle the case where we are in column 0 but not on the first
   // character of the line and the user wants us to show us a
   // special character (via 'listchars' option "precedes:<char>").
   if (lcs_prec_todo != NUL
       && wp->w_p_list
       && (wp->w_p_wrap ? (wp->w_skipcol > 0 && wlv.row == 0) : wp->w_leftcol > 0)
       && wlv.filler_todo <= 0
       && wlv.skip_cells <= 0
       && mb_schar != NUL) {
     lcs_prec_todo = NUL;
     if (schar_cells(mb_schar) > 1) {
       // Double-width character being overwritten by the "precedes"
       // character, need to fill up half the character.
       wlv.sc_extra = schar_from_ascii(MB_FILLER_CHAR);
       wlv.sc_final = NUL;
       if (wlv.n_extra > 0) {
         assert(wlv.p_extra != NULL);
         n_extra_next = wlv.n_extra;
         extra_attr_next = wlv.extra_attr;
         wlv.n_attr = MAX(wlv.n_attr + 1, 2);
       } else {
         wlv.n_attr = 2;
       }
       wlv.n_extra = 1;
       wlv.extra_attr = win_hl_attr(wp, HLF_AT);
     }
     mb_schar = wp->w_p_lcs_chars.prec;
     mb_c = schar_get_first_codepoint(mb_schar);
     saved_attr3 = wlv.char_attr;  // save current attr
     wlv.char_attr = win_hl_attr(wp, HLF_AT);  // overwriting char_attr
     n_attr3 = 1;
   }

   // At end of the text line or just after the last character.
   if (mb_schar == NUL && eol_hl_off == 0) {
     // flag to indicate whether prevcol equals startcol of search_hl or
     // one of the matches
     const bool prevcol_hl_flag = get_prevcol_hl_flag(wp, &screen_search_hl,
                                                      (colnr_T)(ptr - line) - 1);

     // Invert at least one char, used for Visual and empty line or
     // highlight match at end of line. If it's beyond the last
     // char on the screen, just overwrite that one (tricky!)  Not
     // needed when a '$' was displayed for 'list'.
     if (lcs_eol_todo
         && ((area_attr != 0 && wlv.vcol == wlv.fromcol
              && (VIsual_mode != Ctrl_V
                  || lnum == VIsual.lnum
                  || lnum == curwin->w_cursor.lnum))
             // highlight 'hlsearch' match at end of line
             || prevcol_hl_flag)) {
       int n = 0;

       if (wlv.col >= view_width) {
         n = -1;
       }
       if (n != 0) {
         // At the window boundary, highlight the last character
         // instead (better than nothing).
         wlv.off += n;
         wlv.col += n;
       } else {
         // Add a blank character to highlight.
         linebuf_char[wlv.off] = schar_from_ascii(' ');
       }
       if (area_attr == 0 && !has_fold) {
         // Use attributes from match with highest priority among
         // 'search_hl' and the match list.
         get_search_match_hl(wp,
                             &screen_search_hl,
                             (colnr_T)(ptr - line),
                             &wlv.char_attr);
       }

       const int eol_attr = wlv.cul_attr
                            ? hl_combine_attr(wlv.cul_attr, wlv.char_attr)
                            : wlv.char_attr;

       linebuf_attr[wlv.off] = eol_attr;
       linebuf_vcol[wlv.off] = wlv.vcol;
       wlv.col++;
       wlv.off++;
       wlv.vcol++;
       eol_hl_off = 1;
     }
   }

   // At end of the text line.
   if (mb_schar == NUL) {
     // Highlight 'cursorcolumn' & 'colorcolumn' past end of the line.

     // check if line ends before left margin
     wlv.vcol = MAX(wlv.vcol, start_vcol + wlv.col - win_col_off(wp));
     // Get rid of the boguscols now, we want to draw until the right
     // edge for 'cursorcolumn'.
     wlv.col -= wlv.boguscols;
     wlv.boguscols = 0;

     advance_color_col(&wlv, vcol_hlc(wlv));

     // Make sure alignment is the same regardless
     // if listchars=eol:X is used or not.
     const int eol_skip = (lcs_eol_todo && eol_hl_off == 0 ? 1 : 0);

     if (has_decor) {
       decor_redraw_eol(wp, &decor_state, &wlv.line_attr, wlv.col + eol_skip);
     }

     for (int i = wlv.col; i < view_width; i++) {
       linebuf_vcol[wlv.off + (i - wlv.col)] = wlv.vcol + (i - wlv.col);
     }

     if (((wp->w_p_cuc
           && wp->w_virtcol >= vcol_hlc(wlv) - eol_hl_off
           && wp->w_virtcol < view_width * (ptrdiff_t)(wlv.row - startrow + 1) + start_vcol
           && lnum != wp->w_cursor.lnum)
          || wlv.color_cols || wlv.line_attr_lowprio || wlv.line_attr
          || wlv.diff_hlf != 0 || wp->w_buffer->terminal)) {
       int rightmost_vcol = get_rightmost_vcol(wp, wlv.color_cols);
       const int cuc_attr = win_hl_attr(wp, HLF_CUC);
       const int mc_attr = win_hl_attr(wp, HLF_MC);

       if (wlv.diff_hlf == HLF_TXD || wlv.diff_hlf == HLF_TXA) {
         wlv.diff_hlf = HLF_CHD;
         set_line_attr_for_diff(wp, &wlv);
       }

       const int diff_attr = wlv.diff_hlf != 0
                             ? win_hl_attr(wp, (int)wlv.diff_hlf)
                             : 0;

       const int base_attr = hl_combine_attr(wlv.line_attr_lowprio, diff_attr);
       if (base_attr || wlv.line_attr || wp->w_buffer->terminal) {
         rightmost_vcol = INT_MAX;
       }

       while (wlv.col < view_width) {
         linebuf_char[wlv.off] = schar_from_ascii(' ');

         advance_color_col(&wlv, vcol_hlc(wlv));

         int col_attr = base_attr;

         if (wp->w_p_cuc && vcol_hlc(wlv) == wp->w_virtcol
             && lnum != wp->w_cursor.lnum) {
           col_attr = hl_combine_attr(col_attr, cuc_attr);
         } else if (wlv.color_cols && vcol_hlc(wlv) == *wlv.color_cols) {
           col_attr = hl_combine_attr(col_attr, mc_attr);
         }

         if (wp->w_buffer->terminal && wlv.vcol < TERM_ATTRS_MAX) {
           col_attr = hl_combine_attr(col_attr, term_attrs[wlv.vcol]);
         }

         col_attr = hl_combine_attr(col_attr, wlv.line_attr);

         linebuf_attr[wlv.off] = col_attr;
         // linebuf_vcol[] already filled by the for loop above
         wlv.off++;
         wlv.col++;
         wlv.vcol++;

         if (vcol_hlc(wlv) > rightmost_vcol) {
           break;
         }
       }
     }

     if (kv_size(fold_vt) > 0) {
       draw_virt_text_item(buf, win_col_offset, fold_vt, kHlModeCombine, view_width, 0, 0);
     }
     draw_virt_text(wp, buf, win_col_offset, &wlv.col, wlv.row);
     // Set increasing virtual columns in grid->vcols[] to set correct curswant
     // (or "coladd" for 'virtualedit') when clicking after end of line.
     wlv_put_linebuf(wp, &wlv, wlv.col, true, bg_attr, SLF_INC_VCOL);
     wlv.row++;

     // Update w_cline_height and w_cline_folded if the cursor line was
     // updated (saves a call to plines_win() later).
     if (in_curline) {
       curwin->w_cline_row = startrow;
       curwin->w_cline_height = wlv.row - startrow;
       curwin->w_cline_folded = has_fold;
       curwin->w_valid |= (VALID_CHEIGHT|VALID_CROW);
     }

     break;
   }

   // Show "extends" character from 'listchars' if beyond the line end.
   const schar_T lcs_ext = get_lcs_ext(wp);
   if (lcs_ext != NUL
       && wlv.filler_todo <= 0
       && wlv.col == view_width - 1
       && !has_foldtext) {
     if (has_decor && *ptr == NUL && lcs_eol == 0 && lcs_eol_todo) {
       // Tricky: there might be a virtual text just _after_ the last char
       decor_redraw_col(wp, (colnr_T)(ptr - line), -1, false, &decor_state);
     }
     if (*ptr != NUL
         || (lcs_eol > 0 && lcs_eol_todo)
         || (wlv.n_extra > 0 && (wlv.sc_extra != NUL || *wlv.p_extra != NUL))
         || (may_have_inline_virt && has_more_inline_virt(&wlv, ptr - line))) {
       mb_schar = lcs_ext;
       wlv.char_attr = win_hl_attr(wp, HLF_AT);
       mb_c = schar_get_first_codepoint(mb_schar);
     }
   }

   advance_color_col(&wlv, vcol_hlc(wlv));

   // Highlight the cursor column if 'cursorcolumn' is set.  But don't
   // highlight the cursor position itself.
   // Also highlight the 'colorcolumn' if it is different than
   // 'cursorcolumn'
   vcol_save_attr = -1;
   if (!lnum_in_visual_area
       && search_attr == 0
       && area_attr == 0
       && wlv.filler_todo <= 0) {
     if (wp->w_p_cuc && vcol_hlc(wlv) == wp->w_virtcol
         && lnum != wp->w_cursor.lnum) {
       vcol_save_attr = wlv.char_attr;
       wlv.char_attr = hl_combine_attr(win_hl_attr(wp, HLF_CUC), wlv.char_attr);
     } else if (wlv.color_cols && vcol_hlc(wlv) == *wlv.color_cols) {
       vcol_save_attr = wlv.char_attr;
       wlv.char_attr = hl_combine_attr(win_hl_attr(wp, HLF_MC), wlv.char_attr);
     }
   }

   if (wlv.filler_todo <= 0) {
     // Apply lowest-priority line attr now, so everything can override it.
     int low = wlv.line_attr_lowprio;
     int high = wlv.char_attr;

     if (wlv.line_attr_lowprio != 0) {
       HlAttrs line_ae = syn_attr2entry(wlv.line_attr_lowprio);
       HlAttrs char_ae = syn_attr2entry(wlv.char_attr);
       int win_normal_bg = normal_bg;
       int win_normal_cterm_bg = cterm_normal_bg_color;

       // Get window-local Normal background (respects 'winhighlight' option).
       if (bg_attr != 0) {
         HlAttrs norm_ae = syn_attr2entry(bg_attr);
         win_normal_bg = norm_ae.rgb_bg_color;
         win_normal_cterm_bg = norm_ae.cterm_bg_color;
       }
       bool char_is_normal_bg = ui_rgb_attached()
                                ? (char_ae.rgb_bg_color == win_normal_bg)
                                : (char_ae.cterm_bg_color == win_normal_cterm_bg);

       // If line has background (CursorLine) and char's background equals Normal's background,
       // reverse the combination order to let CursorLine override normal_bg.
       if ((line_ae.rgb_bg_color >= 0 || line_ae.cterm_bg_color > 0) && char_is_normal_bg) {
         low = wlv.char_attr;
         high = wlv.line_attr_lowprio;
       }
     }
     wlv.char_attr = hl_combine_attr(low, high);
   }

   if (wlv.filler_todo <= 0) {
     vcol_prev = wlv.vcol;
   }

   // Store character to be displayed.
   // Skip characters that are left of the screen for 'nowrap'.
   if (wlv.filler_todo > 0) {
     // TODO(bfredl): the main render loop should get called also with the virtual
     // lines chunks, so we get line wrapping and other Nice Things.
   } else if (wlv.skip_cells <= 0) {
     // Store the character.
     linebuf_char[wlv.off] = mb_schar;
     if (multi_attr) {
       linebuf_attr[wlv.off] = multi_attr;
       multi_attr = 0;
     } else {
       linebuf_attr[wlv.off] = wlv.char_attr;
     }

     linebuf_vcol[wlv.off] = wlv.vcol;

     if (schar_cells(mb_schar) > 1) {
       // Need to fill two screen columns.
       wlv.off++;
       wlv.col++;
       // UTF-8: Put a 0 in the second screen char.
       linebuf_char[wlv.off] = 0;
       linebuf_attr[wlv.off] = linebuf_attr[wlv.off - 1];

       linebuf_vcol[wlv.off] = ++wlv.vcol;

       // When "wlv.tocol" is halfway through a character, set it to the end
       // of the character, otherwise highlighting won't stop.
       if (wlv.tocol == wlv.vcol) {
         wlv.tocol++;
       }
     }
     wlv.off++;
     wlv.col++;
   } else if (wp->w_p_cole > 0 && is_concealing) {
     bool concealed_wide = schar_cells(mb_schar) > 1;

     wlv.skip_cells--;
     wlv.vcol_off_co++;
     if (concealed_wide) {
       // When a double-width char is concealed,
       // need to advance one more virtual column.
       wlv.vcol++;
       wlv.vcol_off_co++;
     }

     if (wlv.n_extra > 0) {
       wlv.vcol_off_co += wlv.n_extra;
     }

     if (is_wrapped) {
       // Special voodoo required if 'wrap' is on.
       //
       // Advance the column indicator to force the line
       // drawing to wrap early. This will make the line
       // take up the same screen space when parts are concealed,
       // so that cursor line computations aren't messed up.
       //
       // To avoid the fictitious advance of 'wlv.col' causing
       // trailing junk to be written out of the screen line
       // we are building, 'boguscols' keeps track of the number
       // of bad columns we have advanced.
       if (wlv.n_extra > 0) {
         wlv.vcol += wlv.n_extra;
         wlv.col += wlv.n_extra;
         wlv.boguscols += wlv.n_extra;
         wlv.n_extra = 0;
         wlv.n_attr = 0;
       }

       if (concealed_wide) {
         // Need to fill two screen columns.
         wlv.boguscols++;
         wlv.col++;
       }

       wlv.boguscols++;
       wlv.col++;
     } else {
       if (wlv.n_extra > 0) {
         wlv.vcol += wlv.n_extra;
         wlv.n_extra = 0;
         wlv.n_attr = 0;
       }
     }
   } else {
     wlv.skip_cells--;
   }

   // The skipped cells need to be accounted for in vcol.
   if (wlv.skipped_cells > 0) {
     wlv.vcol += wlv.skipped_cells;
     wlv.skipped_cells = 0;
   }

   // Only advance the "wlv.vcol" when after the 'number' or
   // 'relativenumber' column.
   if (wlv.filler_todo <= 0) {
     wlv.vcol++;
   }

   if (vcol_save_attr >= 0) {
     wlv.char_attr = vcol_save_attr;
   }

   // restore attributes after "precedes" in 'listchars'
   if (n_attr3 > 0 && --n_attr3 == 0) {
     wlv.char_attr = saved_attr3;
   }

   // restore attributes after last 'listchars' or 'number' char
   if (wlv.n_attr > 0 && --wlv.n_attr == 0) {
     wlv.char_attr = saved_attr2;
   }

   if (has_decor && wlv.filler_todo <= 0 && wlv.col >= view_width) {
     // At the end of screen line: might need to peek for decorations just after
     // this position.
     if (is_wrapped && wlv.n_extra == 0) {
       decor_redraw_col(wp, (colnr_T)(ptr - line), -3, false, &decor_state);
       // Check position/hiding of virtual text again on next screen line.
       decor_need_recheck = true;
     } else if (!is_wrapped) {
       // Without wrapping, we might need to display right_align and win_col
       // virt_text for the entire text line.
       decor_recheck_draw_col(-1, true, &decor_state);
       decor_redraw_col(wp, MAXCOL, -1, true, &decor_state);
     }
   }

end_check:
   // At end of screen line and there is more to come: Display the line
   // so far.  If there is no more to display it is caught above.
   if (wlv.col >= view_width && (!has_foldtext || virt_line_index >= 0)
       && (wlv.col <= leftcols_width
           || *ptr != NUL
           || wlv.filler_todo > 0
           || (wp->w_p_list && wp->w_p_lcs_chars.eol != NUL && lcs_eol_todo)
           || (wlv.n_extra != 0 && (wlv.sc_extra != NUL || *wlv.p_extra != NUL))
           || (may_have_inline_virt && has_more_inline_virt(&wlv, ptr - line)))) {
     int grid_width = wp->w_grid.target->cols;
     const bool wrap = is_wrapped                      // Wrapping enabled (not a folded line).
                       && wlv.filler_todo <= 0         // Not drawing diff filler lines.
                       && lcs_eol_todo                 // Haven't printed the lcs_eol character.
                       && wlv.row != endrow - 1        // Not the last line being displayed.
                       && view_width == grid_width     // Window spans the width of its grid.
                       && !wp->w_p_rl;                 // Not right-to-left.

     int draw_col = wlv.col - wlv.boguscols;

     for (int i = draw_col; i < view_width; i++) {
       linebuf_vcol[wlv.off + (i - draw_col)] = wlv.vcol - 1;
     }

     // Apply 'cursorline' highlight.
     if (wlv.boguscols != 0 && (wlv.line_attr_lowprio != 0 || wlv.line_attr != 0)) {
       int attr = hl_combine_attr(wlv.line_attr_lowprio, wlv.line_attr);
       while (draw_col < view_width) {
         linebuf_char[wlv.off] = schar_from_char(' ');
         linebuf_attr[wlv.off] = attr;
         // linebuf_vcol[] already filled by the for loop above
         wlv.off++;
         draw_col++;
       }
     }

     if (virt_line_index >= 0) {
       draw_virt_text_item(buf,
                           virt_line_flags & kVLLeftcol ? 0 : win_col_offset,
                           kv_A(virt_lines, virt_line_index).line,
                           kHlModeReplace,
                           view_width,
                           0,
                           virt_line_flags & kVLScroll ? wp->w_leftcol : 0);
     } else if (wlv.filler_todo <= 0) {
       draw_virt_text(wp, buf, win_col_offset, &draw_col, wlv.row);
     }

     wlv_put_linebuf(wp, &wlv, draw_col, true, bg_attr, wrap ? SLF_WRAP : 0);
     if (wrap) {
       int current_row = wlv.row;
       int dummy_col = 0;  // unused
       ScreenGrid *current_grid = grid_adjust(grid, &current_row, &dummy_col);

       // Force a redraw of the first column of the next line.
       current_grid->attrs[current_grid->line_offset[current_row + 1]] = -1;
     }

     wlv.boguscols = 0;
     wlv.vcol_off_co = 0;
     wlv.row++;

     // When not wrapping and finished diff lines, break here.
     if (!is_wrapped && wlv.filler_todo <= 0) {
       break;
     }

     // When the window is too narrow draw all "@" lines.
     if (wlv.col <= leftcols_width) {
       win_draw_end(wp, schar_from_ascii('@'), true, wlv.row, wp->w_view_height, HLF_AT);
       set_empty_rows(wp, wlv.row);
       wlv.row = endrow;
     }

     // When line got too long for screen break here.
     if (wlv.row == endrow) {
       wlv.row++;
       break;
     }

     win_line_start(wp, &wlv);
     draw_cols = true;

     lcs_prec_todo = wp->w_p_lcs_chars.prec;
     if (wlv.filler_todo <= 0) {
       wlv.need_showbreak = true;
     }
     if (statuscol.draw && vim_strchr(p_cpo, CPO_NUMCOL)
         && wlv.row > startrow + wlv.filler_lines) {
       statuscol.draw = false;  // don't draw status column if "n" is in 'cpo'
     }
     wlv.filler_todo--;
     virt_line_index = -1;
     virt_line_flags = 0;
     // When the filler lines are actually below the last line of the
     // file, or we are not drawing text for this line, break here.
     if (wlv.filler_todo == 0 && (wp->w_botfill || !draw_text)) {
       break;
     }
   }
 }     // for every character in the line

 clear_virttext(&fold_vt);
 kv_destroy(virt_lines);
 xfree(foldtext_free);
 return wlv.row;
}

/// Call grid_put_linebuf() using values from "wlv".
/// Also takes care of putting "<<<" on the first line for 'smoothscroll'
/// when 'showbreak' is not set.
///
/// @param clear_end  clear until the end of the screen line.
/// @param flags  for grid_put_linebuf(), but shouldn't contain SLF_RIGHTLEFT.
static void wlv_put_linebuf(win_T *wp, const winlinevars_T *wlv, int endcol, bool clear_end,
                           int bg_attr, int flags)
{
 GridView *grid = &wp->w_grid;

 int startcol = 0;
 int clear_width = clear_end ? wp->w_view_width : endcol;

 assert(!(flags & SLF_RIGHTLEFT));
 if (wp->w_p_rl) {
   linebuf_mirror(&startcol, &endcol, &clear_width, wp->w_view_width);
   flags |= SLF_RIGHTLEFT;
 }

 // Take care of putting "<<<" on the first line for 'smoothscroll'.
 if (wlv->row == 0 && wp->w_skipcol > 0
     // do not overwrite the 'showbreak' text with "<<<"
     && *get_showbreak_value(wp) == NUL
     // do not overwrite the 'listchars' "precedes" text with "<<<"
     && !(wp->w_p_list && wp->w_p_lcs_chars.prec != 0)) {
   int off = 0;
   if (wp->w_p_nu && wp->w_p_rnu) {
     // do not overwrite the line number, change "123 text" to "123<<<xt".
     while (off < wp->w_view_width && ascii_isdigit(schar_get_ascii(linebuf_char[off]))) {
       off++;
     }
   }

   for (int i = 0; i < 3 && off < wp->w_view_width; i++) {
     if (off + 1 < wp->w_view_width && linebuf_char[off + 1] == NUL) {
       // When the first half of a double-width character is
       // overwritten, change the second half to a space.
       linebuf_char[off + 1] = schar_from_ascii(' ');
     }
     linebuf_char[off] = schar_from_ascii('<');
     linebuf_attr[off] = HL_ATTR(HLF_AT);
     off++;
   }
 }

 int row = wlv->row;
 int coloff = 0;
 ScreenGrid *g = grid_adjust(grid, &row, &coloff);
 grid_put_linebuf(g, row, coloff, startcol, endcol, clear_width, bg_attr, 0, wlv->vcol - 1, flags);
}

static int decor_providers_setup(int rows_to_draw, bool draw_from_line_start, linenr_T lnum,
                                colnr_T col, win_T *wp)
{
 // Approximate the number of bytes that will be drawn.
 // Assume we're dealing with 1-cell ascii and ignore
 // the effects of 'linebreak', 'breakindent', etc.
 int rem_vcols;
 if (wp->w_p_wrap) {
   int width = wp->w_view_width - win_col_off(wp);
   int width2 = width + win_col_off2(wp);

   int first_row_width = draw_from_line_start ? width : width2;
   rem_vcols = first_row_width + (rows_to_draw - 1) * width2;
 } else {
   rem_vcols = wp->w_view_height - win_col_off(wp);
 }

 // Call it here since we need to invalidate the line pointer anyway.
 decor_providers_invoke_line(wp, lnum - 1);
 validate_virtcol(wp);

 return invoke_range_next(wp, lnum, col, rem_vcols + 1);
}

/// @return New begin column, or INT_MAX.
static int invoke_range_next(win_T *wp, int lnum, colnr_T begin_col, colnr_T col_off)
{
 char const *const line = ml_get_buf(wp->w_buffer, lnum);
 int const line_len = ml_get_buf_len(wp->w_buffer, lnum);
 col_off = MAX(col_off, 1);

 colnr_T new_col;
 if (col_off <= line_len - begin_col) {
   int end_col = begin_col + col_off;
   end_col += mb_off_next(line, line + end_col);
   decor_providers_invoke_range(wp, lnum - 1, begin_col, lnum - 1, end_col);
   validate_virtcol(wp);
   new_col = end_col;
 } else {
   decor_providers_invoke_range(wp, lnum - 1, begin_col, lnum, 0);
   validate_virtcol(wp);
   new_col = INT_MAX;
 }

 return new_col;
}