ftsynth.c (5374B)
1 /**************************************************************************** 2 * 3 * ftsynth.c 4 * 5 * FreeType synthesizing code for emboldening and slanting (body). 6 * 7 * Copyright (C) 2000-2025 by 8 * David Turner, Robert Wilhelm, and Werner Lemberg. 9 * 10 * This file is part of the FreeType project, and may only be used, 11 * modified, and distributed under the terms of the FreeType project 12 * license, LICENSE.TXT. By continuing to use, modify, or distribute 13 * this file you indicate that you have read the license and 14 * understand and accept it fully. 15 * 16 */ 17 18 19 #include <freetype/ftsynth.h> 20 #include <freetype/internal/ftdebug.h> 21 #include <freetype/internal/ftobjs.h> 22 #include <freetype/ftoutln.h> 23 #include <freetype/ftbitmap.h> 24 25 26 /************************************************************************** 27 * 28 * The macro FT_COMPONENT is used in trace mode. It is an implicit 29 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log 30 * messages during execution. 31 */ 32 #undef FT_COMPONENT 33 #define FT_COMPONENT synth 34 35 36 /*************************************************************************/ 37 /*************************************************************************/ 38 /**** ****/ 39 /**** EXPERIMENTAL OBLIQUING SUPPORT ****/ 40 /**** ****/ 41 /*************************************************************************/ 42 /*************************************************************************/ 43 44 /* documentation is in ftsynth.h */ 45 46 FT_EXPORT_DEF( void ) 47 FT_GlyphSlot_Oblique( FT_GlyphSlot slot ) 48 { 49 /* Value '0x0366A' corresponds to a shear angle of about 12 degrees. */ 50 FT_GlyphSlot_Slant( slot, 0x0366A, 0 ); 51 } 52 53 54 /* documentation is in ftsynth.h */ 55 56 FT_EXPORT_DEF( void ) 57 FT_GlyphSlot_Slant( FT_GlyphSlot slot, 58 FT_Fixed xslant, 59 FT_Fixed yslant ) 60 { 61 FT_Matrix transform; 62 FT_Outline* outline; 63 64 65 if ( !slot ) 66 return; 67 68 outline = &slot->outline; 69 70 /* only oblique outline glyphs */ 71 if ( slot->format != FT_GLYPH_FORMAT_OUTLINE ) 72 return; 73 74 /* we don't touch the advance width */ 75 76 /* For italic, simply apply a shear transform */ 77 transform.xx = 0x10000L; 78 transform.yx = -yslant; 79 80 transform.xy = xslant; 81 transform.yy = 0x10000L; 82 83 FT_Outline_Transform( outline, &transform ); 84 } 85 86 87 /*************************************************************************/ 88 /*************************************************************************/ 89 /**** ****/ 90 /**** EXPERIMENTAL EMBOLDENING SUPPORT ****/ 91 /**** ****/ 92 /*************************************************************************/ 93 /*************************************************************************/ 94 95 96 /* documentation is in ftsynth.h */ 97 98 FT_EXPORT_DEF( void ) 99 FT_GlyphSlot_Embolden( FT_GlyphSlot slot ) 100 { 101 FT_GlyphSlot_AdjustWeight( slot, 0x0AAA, 0x0AAA ); 102 } 103 104 105 FT_EXPORT_DEF( void ) 106 FT_GlyphSlot_AdjustWeight( FT_GlyphSlot slot, 107 FT_Fixed xdelta, 108 FT_Fixed ydelta ) 109 { 110 FT_Library library; 111 FT_Size size; 112 FT_Error error; 113 FT_Pos xstr, ystr; 114 115 116 if ( !slot ) 117 return; 118 119 library = slot->library; 120 size = slot->face->size; 121 122 if ( slot->format != FT_GLYPH_FORMAT_OUTLINE && 123 slot->format != FT_GLYPH_FORMAT_BITMAP ) 124 return; 125 126 /* express deltas in pixels in 26.6 format */ 127 xstr = (FT_Pos)size->metrics.x_ppem * xdelta / 1024; 128 ystr = (FT_Pos)size->metrics.y_ppem * ydelta / 1024; 129 130 if ( slot->format == FT_GLYPH_FORMAT_OUTLINE ) 131 FT_Outline_EmboldenXY( &slot->outline, xstr, ystr ); 132 133 else /* slot->format == FT_GLYPH_FORMAT_BITMAP */ 134 { 135 /* round to full pixels */ 136 xstr &= ~63; 137 if ( xstr == 0 ) 138 xstr = 1 << 6; 139 ystr &= ~63; 140 141 /* 142 * XXX: overflow check for 16-bit system, for compatibility 143 * with FT_GlyphSlot_Embolden() since FreeType 2.1.10. 144 * unfortunately, this function returns no information 145 * about the cause of error. 146 */ 147 if ( ( ystr >> 6 ) > FT_INT_MAX || ( ystr >> 6 ) < FT_INT_MIN ) 148 { 149 FT_TRACE1(( "FT_GlyphSlot_Embolden:" )); 150 FT_TRACE1(( "too strong emboldening parameter ystr=%ld\n", ystr )); 151 return; 152 } 153 error = FT_GlyphSlot_Own_Bitmap( slot ); 154 if ( error ) 155 return; 156 157 error = FT_Bitmap_Embolden( library, &slot->bitmap, xstr, ystr ); 158 if ( error ) 159 return; 160 } 161 162 if ( slot->advance.x ) 163 slot->advance.x += xstr; 164 165 if ( slot->advance.y ) 166 slot->advance.y += ystr; 167 168 slot->metrics.width += xstr; 169 slot->metrics.height += ystr; 170 slot->metrics.horiAdvance += xstr; 171 slot->metrics.vertAdvance += ystr; 172 slot->metrics.horiBearingY += ystr; 173 174 /* XXX: 16-bit overflow case must be excluded before here */ 175 if ( slot->format == FT_GLYPH_FORMAT_BITMAP ) 176 slot->bitmap_top += (FT_Int)( ystr >> 6 ); 177 } 178 179 180 /* END */