third_party/harfbuzz/src/harfbuzz-shaper.h

   1 /*
   2  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
   3  *
   4  * This is part of HarfBuzz, an OpenType Layout engine 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 HARFBUZZ_SHAPER_H
  26 #define HARFBUZZ_SHAPER_H
  27
  28 #include "harfbuzz-global.h"
  29 #include "harfbuzz-gdef.h"
  30 #include "harfbuzz-gpos.h"
  31 #include "harfbuzz-gsub.h"
  32 #include "harfbuzz-external.h"
  33 #include "harfbuzz-stream-private.h"
  34
  35 HB_BEGIN_HEADER
  36
  37 #ifdef HB_USE_PACKED_STRUCTS
  38 #pragma pack(push, 1)
  39 #endif
  40
  41 /*
  42    using anything else than signed or unsigned for bitfields in C is non standard,
  43    but accepted by almost all compilers. And it gives a significant reduction in
  44    memory consumption as HB_CharAttributes and HB_GlyphAttributes will not have
  45    a 4 byte alignment
  46 */
  47 #ifdef  __xlC__
  48 typedef unsigned hb_bitfield;
  49 #else
  50 typedef hb_uint8 hb_bitfield;
  51 #endif
  52
  53 typedef enum {
  54         HB_Script_Common,
  55         HB_Script_Greek,
  56         HB_Script_Cyrillic,
  57         HB_Script_Armenian,
  58         HB_Script_Hebrew,
  59         HB_Script_Arabic,
  60         HB_Script_Syriac,
  61         HB_Script_Thaana,
  62         HB_Script_Devanagari,
  63         HB_Script_Bengali,
  64         HB_Script_Gurmukhi,
  65         HB_Script_Gujarati,
  66         HB_Script_Oriya,
  67         HB_Script_Tamil,
  68         HB_Script_Telugu,
  69         HB_Script_Kannada,
  70         HB_Script_Malayalam,
  71         HB_Script_Sinhala,
  72         HB_Script_Thai,
  73         HB_Script_Lao,
  74         HB_Script_Tibetan,
  75         HB_Script_Myanmar,
  76         HB_Script_Georgian,
  77         HB_Script_Hangul,
  78         HB_Script_Ogham,
  79         HB_Script_Runic,
  80         HB_Script_Khmer,
  81         HB_Script_Nko,
  82         HB_Script_Inherited,
  83         HB_ScriptCount = HB_Script_Inherited
  84         /*
  85         HB_Script_Latin = Common,
  86         HB_Script_Ethiopic = Common,
  87         HB_Script_Cherokee = Common,
  88         HB_Script_CanadianAboriginal = Common,
  89         HB_Script_Mongolian = Common,
  90         HB_Script_Hiragana = Common,
  91         HB_Script_Katakana = Common,
  92         HB_Script_Bopomofo = Common,
  93         HB_Script_Han = Common,
  94         HB_Script_Yi = Common,
  95         HB_Script_OldItalic = Common,
  96         HB_Script_Gothic = Common,
  97         HB_Script_Deseret = Common,
  98         HB_Script_Tagalog = Common,
  99         HB_Script_Hanunoo = Common,
 100         HB_Script_Buhid = Common,
 101         HB_Script_Tagbanwa = Common,
 102         HB_Script_Limbu = Common,
 103         HB_Script_TaiLe = Common,
 104         HB_Script_LinearB = Common,
 105         HB_Script_Ugaritic = Common,
 106         HB_Script_Shavian = Common,
 107         HB_Script_Osmanya = Common,
 108         HB_Script_Cypriot = Common,
 109         HB_Script_Braille = Common,
 110         HB_Script_Buginese = Common,
 111         HB_Script_Coptic = Common,
 112         HB_Script_NewTaiLue = Common,
 113         HB_Script_Glagolitic = Common,
 114         HB_Script_Tifinagh = Common,
 115         HB_Script_SylotiNagri = Common,
 116         HB_Script_OldPersian = Common,
 117         HB_Script_Kharoshthi = Common,
 118         HB_Script_Balinese = Common,
 119         HB_Script_Cuneiform = Common,
 120         HB_Script_Phoenician = Common,
 121         HB_Script_PhagsPa = Common,
 122         */
 123 } HB_Script;
 124
 125 typedef struct
 126 {
 127     hb_uint32 pos;
 128     hb_uint32 length;
 129     HB_Script script;
 130     hb_uint8 bidiLevel;
 131 } HB_ScriptItem;
 132
 133 typedef enum {
 134     HB_NoBreak,
 135     HB_SoftHyphen,
 136     HB_Break,
 137     HB_ForcedBreak
 138 } HB_LineBreakType;
 139
 140
 141 typedef struct {
 142     /*HB_LineBreakType*/ hb_bitfield lineBreakType  :2;
 143     /*HB_Bool*/ hb_bitfield whiteSpace              :1;     /* A unicode whitespace character, except NBSP, ZWNBSP */
 144     /*HB_Bool*/ hb_bitfield charStop                :1;     /* Valid cursor position (for left/right arrow) */
 145     /*HB_Bool*/ hb_bitfield wordBoundary            :1;
 146     /*HB_Bool*/ hb_bitfield sentenceBoundary        :1;
 147     hb_bitfield unused                  :2;
 148 } HB_CharAttributes;
 149
 150 void HB_GetCharAttributes(const HB_UChar16 *string, hb_uint32 stringLength,
 151                           const HB_ScriptItem *items, hb_uint32 numItems,
 152                           HB_CharAttributes *attributes);
 153
 154 /* requires HB_GetCharAttributes to be called before */
 155 void HB_GetWordBoundaries(const HB_UChar16 *string, hb_uint32 stringLength,
 156                           const HB_ScriptItem *items, hb_uint32 numItems,
 157                           HB_CharAttributes *attributes);
 158
 159 /* requires HB_GetCharAttributes to be called before */
 160 void HB_GetSentenceBoundaries(const HB_UChar16 *string, hb_uint32 stringLength,
 161                               const HB_ScriptItem *items, hb_uint32 numItems,
 162                               HB_CharAttributes *attributes);
 163
 164
 165 typedef enum {
 166     HB_LeftToRight = 0,
 167     HB_RightToLeft = 1
 168 } HB_StringToGlyphsFlags;
 169
 170 typedef enum {
 171     HB_ShaperFlag_Default = 0,
 172     HB_ShaperFlag_NoKerning = 1,
 173     HB_ShaperFlag_UseDesignMetrics = 1 << 1,
 174     /* Arabic vowels in some fonts (Times New Roman, at least) have
 175        non-zero advances, when they should be zero.  Setting this shaper
 176        flag causes us to zero out the advances for mark glyphs. */
 177     HB_ShaperFlag_ForceMarksToZeroWidth = 1 << 2
 178 } HB_ShaperFlag;
 179
 180 /*
 181    highest value means highest priority for justification. Justification is done by first inserting kashidas
 182    starting with the highest priority positions, then stretching spaces, afterwards extending inter char
 183    spacing, and last spacing between arabic words.
 184    NoJustification is for example set for arabic where no Kashida can be inserted or for diacritics.
 185 */
 186 typedef enum {
 187     HB_NoJustification= 0,   /* Justification can't be applied after this glyph */
 188     HB_Arabic_Space   = 1,   /* This glyph represents a space inside arabic text */
 189     HB_Character      = 2,   /* Inter-character justification point follows this glyph */
 190     HB_Space          = 4,   /* This glyph represents a blank outside an Arabic run */
 191     HB_Arabic_Normal  = 7,   /* Normal Middle-Of-Word glyph that connects to the right (begin) */
 192     HB_Arabic_Waw     = 8,   /* Next character is final form of Waw/Ain/Qaf/Fa */
 193     HB_Arabic_BaRa    = 9,   /* Next two chars are Ba + Ra/Ya/AlefMaksura */
 194     HB_Arabic_Alef    = 10,  /* Next character is final form of Alef/Tah/Lam/Kaf/Gaf */
 195     HB_Arabic_HaaDal  = 11,  /* Next character is final form of Haa/Dal/Taa Marbutah */
 196     HB_Arabic_Seen    = 12,  /* Initial or Medial form Of Seen/Sad */
 197     HB_Arabic_Kashida = 13   /* Kashida(U+640) in middle of word */
 198 } HB_JustificationClass;
 199
 200 /* This structure is binary compatible with Uniscribe's SCRIPT_VISATTR. Would be nice to keep
 201  * it like that. If this is a problem please tell Trolltech :)
 202  */
 203 typedef struct {
 204     hb_bitfield justification   :4;  /* Justification class */
 205     hb_bitfield clusterStart    :1;  /* First glyph of representation of cluster */
 206     hb_bitfield mark            :1;  /* needs to be positioned around base char */
 207     hb_bitfield zeroWidth       :1;  /* ZWJ, ZWNJ etc, with no width */
 208     hb_bitfield dontPrint       :1;
 209     hb_bitfield combiningClass  :8;
 210 } HB_GlyphAttributes;
 211
 212 typedef struct HB_FaceRec_ {
 213     HB_Bool isSymbolFont;
 214
 215     HB_GDEF gdef;
 216     HB_GSUB gsub;
 217     HB_GPOS gpos;
 218     HB_Bool supported_scripts[HB_ScriptCount];
 219     HB_Buffer buffer;
 220     HB_Script current_script;
 221     int current_flags; /* HB_ShaperFlags */
 222     HB_Bool has_opentype_kerning;
 223     HB_Bool glyphs_substituted;
 224     HB_GlyphAttributes *tmpAttributes;
 225     unsigned int *tmpLogClusters;
 226     int length;
 227     int orig_nglyphs;
 228 } HB_FaceRec;
 229
 230 typedef HB_Error (*HB_GetFontTableFunc)(void *font, HB_Tag tag, HB_Byte *buffer, HB_UInt *length);
 231
 232 HB_Face HB_NewFace(void *font, HB_GetFontTableFunc tableFunc);
 233 void HB_FreeFace(HB_Face face);
 234
 235 typedef struct {
 236     HB_Fixed x, y;
 237     HB_Fixed width, height;
 238     HB_Fixed xOffset, yOffset;
 239 } HB_GlyphMetrics;
 240
 241 typedef enum {
 242     HB_FontAscent
 243 } HB_FontMetric;
 244
 245 typedef struct {
 246     HB_Bool  (*convertStringToGlyphIndices)(HB_Font font, const HB_UChar16 *string, hb_uint32 length, HB_Glyph *glyphs, hb_uint32 *numGlyphs, HB_Bool rightToLeft);
 247     void     (*getGlyphAdvances)(HB_Font font, const HB_Glyph *glyphs, hb_uint32 numGlyphs, HB_Fixed *advances, int flags /*HB_ShaperFlag*/);
 248     HB_Bool  (*canRender)(HB_Font font, const HB_UChar16 *string, hb_uint32 length);
 249     /* implementation needs to make sure to load a scaled glyph, so /no/ FT_LOAD_NO_SCALE */
 250     HB_Error (*getPointInOutline)(HB_Font font, HB_Glyph glyph, int flags /*HB_ShaperFlag*/, hb_uint32 point, HB_Fixed *xpos, HB_Fixed *ypos, hb_uint32 *nPoints);
 251     void     (*getGlyphMetrics)(HB_Font font, HB_Glyph glyph, HB_GlyphMetrics *metrics);
 252     HB_Fixed (*getFontMetric)(HB_Font font, HB_FontMetric metric);
 253 } HB_FontClass;
 254
 255 typedef struct HB_Font_ {
 256     const HB_FontClass *klass;
 257
 258     /* Metrics */
 259     HB_UShort x_ppem, y_ppem;
 260     HB_16Dot16 x_scale, y_scale;
 261
 262     void *userData;
 263 } HB_FontRec;
 264
 265 #ifdef HB_USE_PACKED_STRUCTS
 266 #pragma pack(pop)
 267 #endif
 268
 269 typedef struct HB_ShaperItem_ HB_ShaperItem;
 270
 271 struct HB_ShaperItem_ {
 272     const HB_UChar16 *string;               /* input: the Unicode UTF16 text to be shaped */
 273     hb_uint32 stringLength;                 /* input: the length of the input in 16-bit words */
 274     HB_ScriptItem item;                     /* input: the current run to be shaped: a run of text all in the same script that is a substring of <string> */
 275     HB_Font font;                           /* input: the font: scale, units and function pointers supplying glyph indices and metrics */
 276     HB_Face face;                           /* input: the shaper state; current script, access to the OpenType tables , etc. */
 277     int shaperFlags;                        /* input (unused) should be set to 0; intended to support flags defined in HB_ShaperFlag */
 278     HB_Bool glyphIndicesPresent;            /* input: true if the <glyphs> array contains glyph indices ready to be shaped */
 279     hb_uint32 initialGlyphCount;            /* input: if glyphIndicesPresent is true, the number of glyph indices in the <glyphs> array */
 280
 281     hb_uint32 num_glyphs;                   /* input: capacity of output arrays <glyphs>, <attributes>, <advances>, <offsets>, and <log_clusters>; */
 282                                             /* output: required capacity (may be larger than actual capacity) */
 283
 284     HB_Glyph *glyphs;                       /* output: <num_glyphs> indices of shaped glyphs */
 285     HB_GlyphAttributes *attributes;         /* output: <num_glyphs> glyph attributes */
 286     HB_Fixed *advances;                     /* output: <num_glyphs> advances */
 287     HB_FixedPoint *offsets;                 /* output: <num_glyphs> offsets */
 288     unsigned short *log_clusters;           /* output: for each output glyph, the index in the input of the start of its logical cluster */
 289
 290     /* internal */
 291     HB_Bool kerning_applied;                /* output: true if kerning was applied by the shaper */
 292 };
 293
 294 HB_Bool HB_ShapeItem(HB_ShaperItem *item);
 295
 296 HB_END_HEADER
 297
 298 #endif