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      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 = 2
    174 } HB_ShaperFlag;
    175 
    176 /*
    177    highest value means highest priority for justification. Justification is done by first inserting kashidas
    178    starting with the highest priority positions, then stretching spaces, afterwards extending inter char
    179    spacing, and last spacing between arabic words.
    180    NoJustification is for example set for arabic where no Kashida can be inserted or for diacritics.
    181 */
    182 typedef enum {
    183     HB_NoJustification= 0,   /* Justification can't be applied after this glyph */
    184     HB_Arabic_Space   = 1,   /* This glyph represents a space inside arabic text */
    185     HB_Character      = 2,   /* Inter-character justification point follows this glyph */
    186     HB_Space          = 4,   /* This glyph represents a blank outside an Arabic run */
    187     HB_Arabic_Normal  = 7,   /* Normal Middle-Of-Word glyph that connects to the right (begin) */
    188     HB_Arabic_Waw     = 8,   /* Next character is final form of Waw/Ain/Qaf/Fa */
    189     HB_Arabic_BaRa    = 9,   /* Next two chars are Ba + Ra/Ya/AlefMaksura */
    190     HB_Arabic_Alef    = 10,  /* Next character is final form of Alef/Tah/Lam/Kaf/Gaf */
    191     HB_Arabic_HaaDal  = 11,  /* Next character is final form of Haa/Dal/Taa Marbutah */
    192     HB_Arabic_Seen    = 12,  /* Initial or Medial form Of Seen/Sad */
    193     HB_Arabic_Kashida = 13   /* Kashida(U+640) in middle of word */
    194 } HB_JustificationClass;
    195 
    196 /* This structure is binary compatible with Uniscribe's SCRIPT_VISATTR. Would be nice to keep
    197  * it like that. If this is a problem please tell Trolltech :)
    198  */
    199 typedef struct {
    200     hb_bitfield justification   :4;  /* Justification class */
    201     hb_bitfield clusterStart    :1;  /* First glyph of representation of cluster */
    202     hb_bitfield mark            :1;  /* needs to be positioned around base char */
    203     hb_bitfield zeroWidth       :1;  /* ZWJ, ZWNJ etc, with no width */
    204     hb_bitfield dontPrint       :1;
    205     hb_bitfield combiningClass  :8;
    206 } HB_GlyphAttributes;
    207 
    208 typedef struct HB_FaceRec_ {
    209     HB_Bool isSymbolFont;
    210 
    211     HB_GDEF gdef;
    212     HB_GSUB gsub;
    213     HB_GPOS gpos;
    214     HB_Bool supported_scripts[HB_ScriptCount];
    215     HB_Buffer buffer;
    216     HB_Script current_script;
    217     int current_flags; /* HB_ShaperFlags */
    218     HB_Bool has_opentype_kerning;
    219     HB_Bool glyphs_substituted;
    220     HB_GlyphAttributes *tmpAttributes;
    221     unsigned int *tmpLogClusters;
    222     int length;
    223     int orig_nglyphs;
    224 } HB_FaceRec;
    225 
    226 typedef HB_Error (*HB_GetFontTableFunc)(void *font, HB_Tag tag, HB_Byte *buffer, HB_UInt *length);
    227 
    228 HB_Face HB_NewFace(void *font, HB_GetFontTableFunc tableFunc);
    229 void HB_FreeFace(HB_Face face);
    230 
    231 typedef struct {
    232     HB_Fixed x, y;
    233     HB_Fixed width, height;
    234     HB_Fixed xOffset, yOffset;
    235 } HB_GlyphMetrics;
    236 
    237 typedef enum {
    238     HB_FontAscent
    239 } HB_FontMetric;
    240 
    241 typedef struct {
    242     HB_Bool  (*convertStringToGlyphIndices)(HB_Font font, const HB_UChar16 *string, hb_uint32 length, HB_Glyph *glyphs, hb_uint32 *numGlyphs, HB_Bool rightToLeft);
    243     void     (*getGlyphAdvances)(HB_Font font, const HB_Glyph *glyphs, hb_uint32 numGlyphs, HB_Fixed *advances, int flags /*HB_ShaperFlag*/);
    244     HB_Bool  (*canRender)(HB_Font font, const HB_UChar16 *string, hb_uint32 length);
    245     /* implementation needs to make sure to load a scaled glyph, so /no/ FT_LOAD_NO_SCALE */
    246     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);
    247     void     (*getGlyphMetrics)(HB_Font font, HB_Glyph glyph, HB_GlyphMetrics *metrics);
    248     HB_Fixed (*getFontMetric)(HB_Font font, HB_FontMetric metric);
    249 } HB_FontClass;
    250 
    251 typedef struct HB_Font_ {
    252     const HB_FontClass *klass;
    253 
    254     /* Metrics */
    255     HB_UShort x_ppem, y_ppem;
    256     HB_16Dot16 x_scale, y_scale;
    257 
    258     void *userData;
    259 } HB_FontRec;
    260 
    261 #ifdef HB_USE_PACKED_STRUCTS
    262 #pragma pack(pop)
    263 #endif
    264 
    265 typedef struct HB_ShaperItem_ HB_ShaperItem;
    266 
    267 struct HB_ShaperItem_ {
    268     const HB_UChar16 *string;               /* input: the Unicode UTF16 text to be shaped */
    269     hb_uint32 stringLength;                 /* input: the length of the input in 16-bit words */
    270     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> */
    271     HB_Font font;                           /* input: the font: scale, units and function pointers supplying glyph indices and metrics */
    272     HB_Face face;                           /* input: the shaper state; current script, access to the OpenType tables , etc. */
    273     int shaperFlags;                        /* input (unused) should be set to 0; intended to support flags defined in HB_ShaperFlag */
    274     HB_Bool glyphIndicesPresent;            /* input: true if the <glyphs> array contains glyph indices ready to be shaped */
    275     hb_uint32 initialGlyphCount;            /* input: if glyphIndicesPresent is true, the number of glyph indices in the <glyphs> array */
    276 
    277     hb_uint32 num_glyphs;                   /* input: capacity of output arrays <glyphs>, <attributes>, <advances>, <offsets>, and <log_clusters>; */
    278                                             /* output: required capacity (may be larger than actual capacity) */
    279 
    280     HB_Glyph *glyphs;                       /* output: <num_glyphs> indices of shaped glyphs */
    281     HB_GlyphAttributes *attributes;         /* output: <num_glyphs> glyph attributes */
    282     HB_Fixed *advances;                     /* output: <num_glyphs> advances */
    283     HB_FixedPoint *offsets;                 /* output: <num_glyphs> offsets */
    284     unsigned short *log_clusters;           /* output: for each output glyph, the index in the input of the start of its logical cluster */
    285 
    286     /* internal */
    287     HB_Bool kerning_applied;                /* output: true if kerning was applied by the shaper */
    288 };
    289 
    290 HB_Bool HB_ShapeItem(HB_ShaperItem *item);
    291 
    292 HB_END_HEADER
    293 
    294 #endif
    295