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The Tor Browser
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hb-paint-extents.hh (3594B)

      1 /*
      2 * Copyright © 2022 Behdad Esfahbod
      3 *
      4 *  This is part of HarfBuzz, a text shaping library.
      5 *
      6 * Permission is hereby granted, without written agreement and without
      7 * license or royalty fees, to use, copy, modify, and distribute this
      8 * software and its documentation for any purpose, provided that the
      9 * above copyright notice and the following two paragraphs appear in
     10 * all copies of this software.
     11 *
     12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
     13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
     14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
     15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     16 * DAMAGE.
     17 *
     18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
     19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
     20 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
     21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
     22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
     23 */
     24 
     25 #ifndef HB_PAINT_EXTENTS_HH
     26 #define HB_PAINT_EXTENTS_HH
     27 
     28 #include "hb.hh"
     29 #include "hb-paint.h"
     30 
     31 #include "hb-geometry.hh"
     32 
     33 
     34 typedef struct  hb_paint_extents_context_t hb_paint_extents_context_t;
     35 
     36 struct hb_paint_extents_context_t
     37 {
     38  void clear ()
     39  {
     40    transforms.clear ();
     41    clips.clear ();
     42    groups.clear ();
     43 
     44    transforms.push (hb_transform_t<>{});
     45    clips.push (hb_bounds_t<>{hb_bounds_t<>::UNBOUNDED});
     46    groups.push (hb_bounds_t<>{hb_bounds_t<>::EMPTY});
     47  }
     48 
     49  hb_paint_extents_context_t ()
     50  {
     51    clear ();
     52  }
     53 
     54  hb_extents_t<> get_extents ()
     55  {
     56    return groups.tail().extents;
     57  }
     58 
     59  bool is_bounded ()
     60  {
     61    return groups.tail().status != hb_bounds_t<>::UNBOUNDED;
     62  }
     63 
     64  void push_transform (const hb_transform_t<> &trans)
     65  {
     66    hb_transform_t<> t = transforms.tail ();
     67    t.multiply (trans);
     68    transforms.push (t);
     69  }
     70 
     71  void pop_transform ()
     72  {
     73    transforms.pop ();
     74  }
     75 
     76  void push_clip (hb_extents_t<> extents)
     77  {
     78    /* Transform extents and push a new clip. */
     79    const hb_transform_t<> &t = transforms.tail ();
     80    t.transform_extents (extents);
     81 
     82    auto bounds = hb_bounds_t<> {extents};
     83    bounds.intersect (clips.tail ());
     84 
     85    clips.push (bounds);
     86  }
     87 
     88  void pop_clip ()
     89  {
     90    clips.pop ();
     91  }
     92 
     93  void push_group ()
     94  {
     95    groups.push (hb_bounds_t<> {hb_bounds_t<>::EMPTY});
     96  }
     97 
     98  void pop_group (hb_paint_composite_mode_t mode)
     99  {
    100    const hb_bounds_t<> src_bounds = groups.pop ();
    101    hb_bounds_t<> &backdrop_bounds = groups.tail ();
    102 
    103    // https://learn.microsoft.com/en-us/typography/opentype/spec/colr#format-32-paintcomposite
    104    switch ((int) mode)
    105    {
    106      case HB_PAINT_COMPOSITE_MODE_CLEAR:
    107 backdrop_bounds.status = hb_bounds_t<>::EMPTY;
    108 break;
    109      case HB_PAINT_COMPOSITE_MODE_SRC:
    110      case HB_PAINT_COMPOSITE_MODE_SRC_OUT:
    111 backdrop_bounds = src_bounds;
    112 break;
    113      case HB_PAINT_COMPOSITE_MODE_DEST:
    114      case HB_PAINT_COMPOSITE_MODE_DEST_OUT:
    115 break;
    116      case HB_PAINT_COMPOSITE_MODE_SRC_IN:
    117      case HB_PAINT_COMPOSITE_MODE_DEST_IN:
    118 backdrop_bounds.intersect (src_bounds);
    119 break;
    120      default:
    121 backdrop_bounds.union_ (src_bounds);
    122 break;
    123     }
    124  }
    125 
    126  void paint ()
    127  {
    128    const hb_bounds_t<> &clip = clips.tail ();
    129    hb_bounds_t<> &group = groups.tail ();
    130 
    131    group.union_ (clip);
    132  }
    133 
    134  protected:
    135  hb_vector_t<hb_transform_t<>> transforms;
    136  hb_vector_t<hb_bounds_t<>> clips;
    137  hb_vector_t<hb_bounds_t<>> groups;
    138 };
    139 
    140 HB_INTERNAL hb_paint_funcs_t *
    141 hb_paint_extents_get_funcs ();
    142 
    143 
    144 #endif /* HB_PAINT_EXTENTS_HH */