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      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
    116