icuSources/layout/CursiveAttachmentSubtables.cpp

   1 /*
   2  * %W% %E%
   3  *
   4  * (C) Copyright IBM Corp. 1998, 1999, 2000, 2001, 2002 - All Rights Reserved
   5  *
   6  */
   7
   8 #include "LETypes.h"
   9 #include "LEFontInstance.h"
  10 #include "OpenTypeTables.h"
  11 #include "GlyphPositioningTables.h"
  12 #include "CursiveAttachmentSubtables.h"
  13 #include "AnchorTables.h"
  14 #include "GlyphIterator.h"
  15 #include "GlyphPositionAdjustments.h"
  16 #include "OpenTypeUtilities.h"
  17 #include "LESwaps.h"
  18
  19 U_NAMESPACE_BEGIN
  20
  21 le_uint32 CursiveAttachmentSubtable::process(GlyphIterator *glyphIterator, const LEFontInstance *fontInstance) const
  22 {
  23     LEGlyphID glyphID       = glyphIterator->getCurrGlyphID();
  24     le_int32  coverageIndex = getGlyphCoverage(glyphID);
  25     le_uint16 eeCount       = SWAPW(entryExitCount);
  26
  27     if (coverageIndex < 0 || coverageIndex >= eeCount) {
  28         glyphIterator->resetCursiveLastExitPoint();
  29         return 0;
  30     }
  31
  32     LEPoint entryAnchor, exitAnchor, pixels;
  33
  34     if (glyphIterator->hasCursiveLastExitPoint() && entryExitRecords[coverageIndex].entryAnchor != 0) {
  35         Offset entryOffset = SWAPW(entryExitRecords[coverageIndex].entryAnchor);
  36
  37         const AnchorTable *entryAnchorTable = (const AnchorTable *) ((char *) this + entryOffset);
  38
  39         entryAnchorTable->getAnchor(glyphID, fontInstance, entryAnchor);
  40         glyphIterator->getCursiveLastExitPoint(exitAnchor);
  41
  42         float anchorDiffX        = exitAnchor.fX - entryAnchor.fX;
  43         float anchorDiffY        = exitAnchor.fY - entryAnchor.fY;
  44         float baselineAdjustment = glyphIterator->getCursiveBaselineAdjustment();
  45
  46         if (glyphIterator->isRightToLeft()) {
  47             LEPoint secondAdvance;
  48
  49             fontInstance->getGlyphAdvance(glyphID, pixels);
  50             fontInstance->pixelsToUnits(pixels, secondAdvance);
  51
  52             glyphIterator->adjustCurrGlyphPositionAdjustment(0, anchorDiffY + baselineAdjustment, -(anchorDiffX + secondAdvance.fX), 0);
  53         } else {
  54             LEPoint firstAdvance;
  55
  56             fontInstance->getGlyphAdvance(glyphIterator->getCursiveLastGlyphID(), pixels);
  57             fontInstance->pixelsToUnits(pixels, firstAdvance);
  58
  59             glyphIterator->adjustCursiveLastGlyphPositionAdjustment(0, 0, anchorDiffX - firstAdvance.fX, 0);
  60             glyphIterator->adjustCurrGlyphPositionAdjustment(0, anchorDiffY + baselineAdjustment, 0, 0);
  61         }
  62
  63         glyphIterator->setCursiveBaselineAdjustment(anchorDiffY + baselineAdjustment);
  64     }
  65
  66     Offset exitOffset = SWAPW(entryExitRecords[coverageIndex].exitAnchor);
  67
  68     if (exitOffset != 0) {
  69         const AnchorTable *exitAnchorTable = (const AnchorTable *) ((char *) this + exitOffset);
  70
  71         exitAnchorTable->getAnchor(glyphID, fontInstance, exitAnchor);
  72
  73         if (!glyphIterator->hasCursiveFirstExitPoint()) {
  74             glyphIterator->setCursiveFirstExitPoint();
  75         }
  76
  77         glyphIterator->setCursiveLastExitPoint(exitAnchor);
  78     } else {
  79         /*
  80          * We've got a glyph which is covered but doesn't have an
  81          * exit point. We call setCursiveLastExitPoint just to set
  82          * the position of this glyph, then resetCursiveLastExitPoint
  83          * to do any baseline adjustments that are required for the
  84          * sequence of attached glyphs.
  85          *
  86          * NOTE: we don't really care about the value of
  87          * extiAnchor, because after we reset the last exit
  88          * point, it won't be used. This is a bit of a hack.
  89          * There should probably be a setCursiveLastExitPoint
  90          * call that doesn't take an anchor...
  91          */
  92         glyphIterator->setCursiveLastExitPoint(exitAnchor);
  93         glyphIterator->resetCursiveLastExitPoint();
  94     }
  95
  96     return 1;
  97 }
  98
  99 U_NAMESPACE_END