harfbuzz-shaper.h revision 57e6107a9d66a9a97b146def0ef38c010f954be6 
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
35HB_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__
48typedef unsigned hb_bitfield;
49#else
50typedef hb_uint8 hb_bitfield;
51#endif
52
53typedef 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
125typedef struct
126{
127    hb_uint32 pos;
128    hb_uint32 length;
129    HB_Script script;
130    hb_uint8 bidiLevel;
131} HB_ScriptItem;
132
133typedef enum {
134    HB_NoBreak,
135    HB_SoftHyphen,
136    HB_Break,
137    HB_ForcedBreak
138} HB_LineBreakType;
139
140
141typedef 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
150void 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 */
155void 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 */
160void HB_GetSentenceBoundaries(const HB_UChar16 *string, hb_uint32 stringLength,
161                              const HB_ScriptItem *items, hb_uint32 numItems,
162                              HB_CharAttributes *attributes);
163
164
165typedef enum {
166    HB_LeftToRight = 0,
167    HB_RightToLeft = 1
168} HB_StringToGlyphsFlags;
169
170typedef 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*/
182typedef 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 */
199typedef 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
208typedef 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
226typedef HB_Error (*HB_GetFontTableFunc)(void *font, HB_Tag tag, HB_Byte *buffer, HB_UInt *length);
227
228HB_Face HB_NewFace(void *font, HB_GetFontTableFunc tableFunc);
229void HB_FreeFace(HB_Face face);
230
231typedef struct {
232    HB_Fixed x, y;
233    HB_Fixed width, height;
234    HB_Fixed xOffset, yOffset;
235} HB_GlyphMetrics;
236
237typedef enum {
238    HB_FontAscent
239} HB_FontMetric;
240
241typedef 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
251typedef 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
265typedef struct HB_ShaperItem_ HB_ShaperItem;
266
267struct 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
290HB_Bool HB_ShapeItem(HB_ShaperItem *item);
291
292HB_END_HEADER
293
294#endif
295