icuSources/layout/MarkToBasePosnSubtables.cpp

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2010 - All Rights Reserved
   4  *
   5  */
   6
   7 #include "LETypes.h"
   8 #include "LEFontInstance.h"
   9 #include "OpenTypeTables.h"
  10 #include "AnchorTables.h"
  11 #include "MarkArrays.h"
  12 #include "GlyphPositioningTables.h"
  13 #include "AttachmentPosnSubtables.h"
  14 #include "MarkToBasePosnSubtables.h"
  15 #include "GlyphIterator.h"
  16 #include "LESwaps.h"
  17
  18 U_NAMESPACE_BEGIN
  19
  20 LEGlyphID MarkToBasePositioningSubtable::findBaseGlyph(GlyphIterator *glyphIterator) const
  21 {
  22     if (glyphIterator->prev()) {
  23         return glyphIterator->getCurrGlyphID();
  24     }
  25
  26     return 0xFFFF;
  27 }
  28
  29 le_int32 MarkToBasePositioningSubtable::process(GlyphIterator *glyphIterator, const LEFontInstance *fontInstance) const
  30 {
  31     LEGlyphID markGlyph = glyphIterator->getCurrGlyphID();
  32     le_int32 markCoverage = getGlyphCoverage((LEGlyphID) markGlyph);
  33
  34     if (markCoverage < 0) {
  35         // markGlyph isn't a covered mark glyph
  36         return 0;
  37     }
  38
  39     LEPoint markAnchor;
  40     const MarkArray *markArray = (const MarkArray *) ((char *) this + SWAPW(markArrayOffset));
  41     le_int32 markClass = markArray->getMarkClass(markGlyph, markCoverage, fontInstance, markAnchor);
  42     le_uint16 mcCount = SWAPW(classCount);
  43
  44     if (markClass < 0 || markClass >= mcCount) {
  45         // markGlyph isn't in the mark array or its
  46         // mark class is too big. The table is mal-formed!
  47         return 0;
  48     }
  49
  50     // FIXME: We probably don't want to find a base glyph before a previous ligature...
  51     GlyphIterator baseIterator(*glyphIterator, (le_uint16) (lfIgnoreMarks /*| lfIgnoreLigatures*/));
  52     LEGlyphID baseGlyph = findBaseGlyph(&baseIterator);
  53     le_int32 baseCoverage = getBaseCoverage((LEGlyphID) baseGlyph);
  54     const BaseArray *baseArray = (const BaseArray *) ((char *) this + SWAPW(baseArrayOffset));
  55     le_uint16 baseCount = SWAPW(baseArray->baseRecordCount);
  56
  57     if (baseCoverage < 0 || baseCoverage >= baseCount) {
  58         // The base glyph isn't covered, or the coverage
  59         // index is too big. The latter means that the
  60         // table is mal-formed...
  61         return 0;
  62     }
  63
  64     const BaseRecord *baseRecord = &baseArray->baseRecordArray[baseCoverage * mcCount];
  65     Offset anchorTableOffset = SWAPW(baseRecord->baseAnchorTableOffsetArray[markClass]);
  66     const AnchorTable *anchorTable = (const AnchorTable *) ((char *) baseArray + anchorTableOffset);
  67     LEPoint baseAnchor, markAdvance, pixels;
  68
  69     if (anchorTableOffset == 0) {
  70         // this means the table is mal-formed...
  71         glyphIterator->setCurrGlyphBaseOffset(baseIterator.getCurrStreamPosition());
  72         return 0;
  73     }
  74
  75     anchorTable->getAnchor(baseGlyph, fontInstance, baseAnchor);
  76
  77     fontInstance->getGlyphAdvance(markGlyph, pixels);
  78     fontInstance->pixelsToUnits(pixels, markAdvance);
  79
  80     float anchorDiffX = baseAnchor.fX - markAnchor.fX;
  81     float anchorDiffY = baseAnchor.fY - markAnchor.fY;
  82
  83     glyphIterator->setCurrGlyphBaseOffset(baseIterator.getCurrStreamPosition());
  84
  85     if (glyphIterator->isRightToLeft()) {
  86         // FIXME: need similar patch to below; also in MarkToLigature and MarkToMark
  87         // (is there a better way to approach this for all the cases?)
  88         glyphIterator->setCurrGlyphPositionAdjustment(anchorDiffX, anchorDiffY, -markAdvance.fX, -markAdvance.fY);
  89     } else {
  90         LEPoint baseAdvance;
  91
  92         fontInstance->getGlyphAdvance(baseGlyph, pixels);
  93
  94         //JK: adjustment needs to account for non-zero advance of any marks between base glyph and current mark
  95         GlyphIterator gi(baseIterator, (le_uint16)0); // copy of baseIterator that won't ignore marks
  96         gi.next(); // point beyond the base glyph
  97         while (gi.getCurrStreamPosition() < glyphIterator->getCurrStreamPosition()) { // for all intervening glyphs (marks)...
  98             LEGlyphID otherMark = gi.getCurrGlyphID();
  99             LEPoint px;
 100             fontInstance->getGlyphAdvance(otherMark, px); // get advance, in case it's non-zero
 101             pixels.fX += px.fX; // and add that to the base glyph's advance
 102             pixels.fY += px.fY;
 103             gi.next();
 104         }
 105         // end of JK patch
 106
 107         fontInstance->pixelsToUnits(pixels, baseAdvance);
 108
 109         glyphIterator->setCurrGlyphPositionAdjustment(anchorDiffX - baseAdvance.fX, anchorDiffY - baseAdvance.fY, -markAdvance.fX, -markAdvance.fY);
 110     }
 111
 112     return 1;
 113 }
 114
 115 U_NAMESPACE_END