gfx/harfbuzz/src/hb-graphite.cc

   1 /*
   2  * Copyright (C) 2009  Martin Hosken
   3  * Copyright (C) 2009  SIL International
   4  *
   5  *  This is part of HarfBuzz, a text shaping library.
   6  *
   7  * Permission is hereby granted, without written agreement and without
   8  * license or royalty fees, to use, copy, modify, and distribute this
   9  * software and its documentation for any purpose, provided that the
  10  * above copyright notice and the following two paragraphs appear in
  11  * all copies of this software.
  12  *
  13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  17  * DAMAGE.
  18  *
  19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  24  */
  25
  26 #include <graphite/GrClient.h>
  27 #include <graphite/ITextSource.h>
  28 #include <graphite/GrData.h>
  29 #include <graphite/GrConstants.h>
  30 #include <graphite/Segment.h>
  31 #include "hb-buffer-private.hh"
  32 #include "hb-font-private.h"
  33 #include "hb-graphite.h"
  34 #include <map>
  35
  36 HB_BEGIN_DECLS
  37
  38
  39 namespace TtfUtil
  40 {
  41 extern int FontAscent(const void *pOS2);
  42 extern int FontDescent(const void *pOS2);
  43 extern int DesignUnits(const void *pHead);
  44 extern bool FontOs2Style(const void *pOS2, bool &fBold, bool &fItalic);
  45 }
  46
  47 typedef struct _featureSetting {
  48     unsigned int id;
  49     int value;
  50 } featureSetting;
  51
  52 class HbGrBufferTextSrc : public gr::ITextSource
  53 {
  54 public:
  55   HbGrBufferTextSrc(hb_buffer_t *buff, hb_feature_t *feats, unsigned int num_features)
  56   {
  57     hb_feature_t *aFeat = feats;
  58     featureSetting *aNewFeat;
  59
  60     buffer = hb_buffer_reference(buff);
  61     features = new featureSetting[num_features];
  62     nFeatures = num_features;
  63     aNewFeat = features;
  64     for (unsigned int i = 0; i < num_features; i++, aFeat++, aNewFeat++)
  65     {
  66         aNewFeat->id = aFeat->tag;
  67         aNewFeat->value = aFeat->value;
  68     }
  69   };
  70   ~HbGrBufferTextSrc() { hb_buffer_destroy(buffer); delete[] features; };
  71   virtual gr::UtfType utfEncodingForm() { return gr::kutf32; };
  72   virtual size_t getLength() { return buffer->len; };
  73   virtual size_t fetch(gr::toffset ichMin, size_t cch, gr::utf32 * prgchBuffer)
  74   {
  75     assert(cch <= buffer->len);
  76     if (cch > buffer->len)
  77       return 0;
  78     for (unsigned int i = ichMin; i < ichMin + cch; i++)
  79       prgchBuffer[i - ichMin] = buffer->info[i].codepoint;
  80     return (cch - ichMin);
  81   };
  82   virtual size_t fetch(gr::toffset ichMin, size_t cch, gr::utf16 * prgchBuffer) { return 0 ;};
  83   virtual size_t fetch(gr::toffset ichMin, size_t cch, gr::utf8 * prgchBuffer) { return 0; };
  84   virtual bool getRightToLeft(gr::toffset ich)
  85   { return hb_buffer_get_direction(buffer) == HB_DIRECTION_RTL; };
  86   virtual unsigned int getDirectionDepth(gr::toffset ich)
  87   { return hb_buffer_get_direction(buffer) == HB_DIRECTION_RTL ? 1 : 0; };
  88   virtual float getVerticalOffset(gr::toffset ich) { return 0; };
  89   virtual gr::isocode getLanguage(gr::toffset ich)
  90   {
  91     gr::isocode aLang;
  92     char *p = (char *)(buffer->language);
  93     int i;
  94     for (i = 0; i < 4; i++)
  95     {
  96       if (p != NULL)
  97         aLang.rgch[i] = *p;
  98       else
  99         aLang.rgch[i] = 0;
 100       if (p && *p)
 101         p++;
 102     }
 103     return aLang;
 104   }
 105
 106   virtual std::pair<gr::toffset, gr::toffset> propertyRange(gr::toffset ich)
 107   { return std::pair<gr::toffset, gr::toffset>(0, buffer->len); };
 108   virtual size_t getFontFeatures(gr::toffset ich, gr::FeatureSetting * prgfset)
 109   {
 110     featureSetting *aFeat = features;
 111     for (unsigned int i = 0; i < nFeatures; i++, aFeat++, prgfset++)
 112     {
 113       prgfset->id = aFeat->id;
 114       prgfset->value = aFeat->value;
 115     }
 116     return nFeatures;
 117   }
 118   virtual bool sameSegment(gr::toffset ich1, gr::toffset ich2) {return true; };
 119
 120 private:
 121   hb_buffer_t   *buffer;
 122   featureSetting   *features;
 123   unsigned int nFeatures;
 124 };
 125
 126 class HbGrFont : public gr::Font
 127 {
 128 public:
 129   HbGrFont(hb_font_t *font, hb_face_t *face) : gr::Font()
 130   { m_font = hb_font_reference(font); m_face = hb_face_reference(face); initfont(); };
 131   ~HbGrFont()
 132   {
 133     std::map<hb_tag_t,hb_blob_t *>::iterator p = m_blobs.begin();
 134     while (p != m_blobs.end())
 135     { hb_blob_destroy((p++)->second); }
 136     hb_font_destroy(m_font);
 137     hb_face_destroy(m_face);
 138   };
 139   HbGrFont (const HbGrFont &font) : gr::Font(font)
 140   {
 141     *this = font;
 142     m_blobs = std::map<hb_tag_t, hb_blob_t *>(font.m_blobs);
 143     std::map<hb_tag_t,hb_blob_t *>::iterator p=m_blobs.begin();
 144     while (p != m_blobs.end()) { hb_blob_reference((*p++).second); }
 145     hb_font_reference(m_font);
 146     hb_face_reference(m_face);
 147   };
 148   virtual HbGrFont *copyThis() { return new HbGrFont(*this); };
 149   virtual bool bold() { return m_bold; };
 150   virtual bool italic() { return m_italic; };
 151   virtual float ascent() { float asc; getFontMetrics(&asc, NULL, NULL); return asc; };
 152   virtual float descent() { float desc; getFontMetrics(NULL, &desc, NULL); return desc; };
 153   virtual float height()
 154   { float asc, desc; getFontMetrics(&asc, &desc, NULL); return (asc + desc); };
 155   virtual unsigned int getDPIx() { return m_font->x_ppem; };
 156   virtual unsigned int getDPIy() { return m_font->y_ppem; };
 157   virtual const void *getTable(gr::fontTableId32 tableID, size_t *pcbsize)
 158   {
 159     hb_blob_t *blob;
 160     std::map<hb_tag_t,hb_blob_t *>::iterator p=m_blobs.find((hb_tag_t)tableID);
 161     if (p == m_blobs.end())
 162     {
 163       blob = hb_face_get_table(m_face, (hb_tag_t)tableID);
 164       m_blobs[(hb_tag_t)tableID] = blob;
 165     }
 166     else
 167     { blob = p->second; }
 168
 169     const char *res = hb_blob_lock(blob);
 170     if (pcbsize)
 171       *pcbsize = hb_blob_get_length(blob);
 172     hb_blob_unlock(blob);
 173     return (const void *)res;
 174   }
 175
 176   virtual void getFontMetrics(float *pAscent, float *pDescent, float *pEmSquare)
 177   {
 178     if (pAscent) *pAscent = 1. * m_ascent * m_font->y_ppem / m_emsquare;
 179     if (pDescent) *pDescent = 1. * m_descent * m_font->y_ppem / m_emsquare;
 180     if (pEmSquare) *pEmSquare = m_font->x_scale;
 181   }
 182   virtual void getGlyphPoint(gr::gid16 glyphID, unsigned int pointNum, gr::Point &pointReturn)
 183   {
 184     hb_position_t x, y;
 185     hb_font_get_contour_point(m_font, m_face, pointNum, glyphID, &x, &y);
 186     pointReturn.x = (float)x;
 187     pointReturn.y = (float)y;
 188   }
 189
 190   virtual void getGlyphMetrics(gr::gid16 glyphID, gr::Rect &boundingBox, gr::Point &advances)
 191   {
 192     hb_glyph_metrics_t metrics;
 193     hb_font_get_glyph_metrics(m_font, m_face, glyphID, &metrics);
 194     boundingBox.top = (metrics.y_offset + metrics.height);
 195     boundingBox.bottom = metrics.y_offset;
 196     boundingBox.left = metrics.x_offset;
 197     boundingBox.right = (metrics.x_offset + metrics.width);
 198     advances.x = metrics.x_advance;
 199     advances.y = metrics.y_advance;
 200 //    fprintf (stderr, "%d: (%d, %d, %d, %d)+(%d, %d)\n", glyphID, metrics.x_offset, metrics.y_offset, metrics.width, metrics.height, metrics.x_advance, metrics.y_advance);
 201   }
 202
 203 private:
 204   HB_INTERNAL void initfont();
 205
 206   hb_font_t *m_font;
 207   hb_face_t *m_face;
 208   float m_ascent;
 209   float m_descent;
 210   float m_emsquare;
 211   bool m_bold;
 212   bool m_italic;
 213   std::map<hb_tag_t, hb_blob_t *> m_blobs;
 214 };
 215
 216 void HbGrFont::initfont()
 217 {
 218   const void *pOS2 = getTable(gr::kttiOs2, NULL);
 219   const void *pHead = getTable(gr::kttiHead, NULL);
 220   TtfUtil::FontOs2Style(pOS2, m_bold, m_italic);
 221   m_ascent = static_cast<float>(TtfUtil::FontAscent(pOS2));
 222   m_descent = static_cast<float>(TtfUtil::FontDescent(pOS2));
 223   m_emsquare = static_cast<float>(TtfUtil::DesignUnits(pHead));
 224 }
 225
 226 void
 227 hb_graphite_shape (hb_font_t    *font,
 228                    hb_face_t    *face,
 229                    hb_buffer_t  *buffer,
 230                    hb_feature_t *features,
 231                    unsigned int  num_features)
 232 {
 233   /* create text source */
 234   HbGrBufferTextSrc   textSrc(buffer, features, num_features);
 235
 236   /* create grfont */
 237   HbGrFont          grfont(font, face);
 238
 239   /* create segment */
 240   int *firsts;
 241   bool *flags;
 242   int numChars;
 243   int numGlyphs;
 244   gr::LayoutEnvironment layout;
 245   std::pair<gr::GlyphIterator, gr::GlyphIterator>glyph_range;
 246   gr::GlyphIterator iGlyph;
 247   hb_codepoint_t *glyph_infos, *pGlyph;
 248   hb_glyph_position_t *pPosition;
 249   int cGlyph = 0;
 250   int cChar = 0;
 251
 252   layout.setStartOfLine(0);
 253   layout.setEndOfLine(0);
 254   layout.setDumbFallback(true);
 255   layout.setJustifier(NULL);
 256   layout.setRightToLeft(false);
 257
 258   gr::RangeSegment pSegment(&grfont, &textSrc, &layout, (gr::toffset)0,
 259         static_cast<gr::toffset>(buffer->len), (gr::Segment *)NULL);
 260
 261   /* fill in buffer from segment */
 262   _hb_buffer_clear_output(buffer);
 263   pSegment.getUniscribeClusters(NULL, 0, &numChars, NULL, 0, &numGlyphs);
 264   firsts = new int[numChars];
 265   flags = new bool[numGlyphs];
 266   glyph_infos = new hb_codepoint_t[numGlyphs];
 267   hb_buffer_ensure(buffer, numGlyphs);
 268   pSegment.getUniscribeClusters(firsts, numChars, NULL, flags, numGlyphs, NULL);
 269   glyph_range = pSegment.glyphs();
 270   for (pGlyph = glyph_infos, iGlyph = glyph_range.first; iGlyph != glyph_range.second;
 271         iGlyph++, pGlyph++)
 272   { *pGlyph = iGlyph->glyphID(); }
 273
 274   while (cGlyph < numGlyphs)
 275   {
 276     if (flags[cGlyph])
 277     {
 278         int oldcChar = cChar++;
 279         int oldcGlyph = cGlyph++;
 280         while (cChar < numChars && firsts[cChar] == firsts[oldcChar]) cChar++;
 281         while (cGlyph < numGlyphs && !flags[cGlyph]) cGlyph++;
 282         _hb_buffer_add_output_glyphs(buffer, cChar - oldcChar, cGlyph - oldcGlyph,
 283                 glyph_infos + oldcGlyph, 0xFFFF, 0xFFFF);
 284     }
 285     else
 286     { cGlyph++; }   /* This should never happen */
 287   }
 288
 289   float curradvx = 0., curradvy = 0.;
 290   for (pPosition = hb_buffer_get_glyph_positions(buffer), iGlyph = glyph_range.first;
 291         iGlyph != glyph_range.second; pPosition++, iGlyph++)
 292   {
 293     pPosition->x_offset = iGlyph->origin() - curradvx;
 294     pPosition->y_offset = iGlyph->yOffset() - curradvy;
 295     pPosition->x_advance = pPosition->x_offset + iGlyph->advanceWidth();
 296     pPosition->y_advance = pPosition->y_offset + iGlyph->advanceHeight();
 297     if (pPosition->x_advance < 0 && iGlyph->logicalIndex() != iGlyph->attachedClusterBase()->logicalIndex())
 298         pPosition->x_advance = 0;
 299     curradvx += pPosition->x_advance;
 300     curradvy += pPosition->y_advance;
 301 //    fprintf(stderr, "%d@(%f, %f)+(%f, %f)\n", iGlyph->glyphID(), iGlyph->origin(), iGlyph->yOffset(), iGlyph->advanceWidth(), iGlyph->advanceHeight());
 302   }
 303
 304   delete[] glyph_infos;
 305   delete[] firsts;
 306   delete[] flags;
 307 }
 308
 309
 310 HB_END_DECLS