fontservices/textshaperplugin/IcuSource/layout/MarkToLigaturePosnSubtables.cpp
changeset 0 1fb32624e06b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fontservices/textshaperplugin/IcuSource/layout/MarkToLigaturePosnSubtables.cpp	Tue Feb 02 02:02:46 2010 +0200
@@ -0,0 +1,103 @@
+/*
+ * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved
+ *
+ */
+
+#include "LETypes.h"
+#include "LEFontInstance.h"
+#include "OpenTypeTables.h"
+#include "AnchorTables.h"
+#include "MarkArrays.h"
+#include "GlyphPositioningTables.h"
+#include "AttachmentPosnSubtables.h"
+#include "MarkToLigaturePosnSubtables.h"
+#include "GlyphIterator.h"
+#include "LESwaps.h"
+
+U_NAMESPACE_BEGIN
+
+LEGlyphID MarkToLigaturePositioningSubtable::findLigatureGlyph(GlyphIterator *glyphIterator) const
+{
+    if (glyphIterator->prev()) {
+        return glyphIterator->getCurrGlyphID();
+    }
+
+    return 0xFFFF;
+}
+
+le_int32 MarkToLigaturePositioningSubtable::process(GlyphIterator *glyphIterator, const LEFontInstance *fontInstance) const
+{
+    LEGlyphID markGlyph = glyphIterator->getCurrGlyphID();
+    le_int32 markCoverage = getGlyphCoverage((LEGlyphID) markGlyph);
+
+    if (markCoverage < 0) {
+        // markGlyph isn't a covered mark glyph
+        return 0;
+    }
+
+    LEPoint markAnchor;
+    const MarkArray *markArray = (const MarkArray *) ((char *) this + SWAPW(markArrayOffset));
+    le_int32 markClass = markArray->getMarkClass(markGlyph, markCoverage, fontInstance, markAnchor);
+    le_uint16 mcCount = SWAPW(classCount);
+
+    if (markClass < 0 || markClass >= mcCount) {
+        // markGlyph isn't in the mark array or its
+        // mark class is too big. The table is mal-formed!
+        return 0;
+    }
+
+    // FIXME: we probably don't want to find a ligature before a previous base glyph...
+    GlyphIterator ligatureIterator(*glyphIterator, (le_uint16) (lfIgnoreMarks /*| lfIgnoreBaseGlyphs*/));
+    LEGlyphID ligatureGlyph = findLigatureGlyph(&ligatureIterator);
+    le_int32 ligatureCoverage = getBaseCoverage((LEGlyphID) ligatureGlyph);
+    const LigatureArray *ligatureArray = (const LigatureArray *) ((char *) this + SWAPW(baseArrayOffset));
+    le_uint16 ligatureCount = SWAPW(ligatureArray->ligatureCount);
+
+    if (ligatureCoverage < 0 || ligatureCoverage >= ligatureCount) {
+        // The ligature glyph isn't covered, or the coverage
+        // index is too big. The latter means that the
+        // table is mal-formed...
+        return 0;
+    }
+
+    le_int32 markPosition = glyphIterator->getCurrStreamPosition();
+    Offset ligatureAttachOffset = SWAPW(ligatureArray->ligatureAttachTableOffsetArray[ligatureCoverage]);
+    const LigatureAttachTable *ligatureAttachTable = (const LigatureAttachTable *) ((char *) ligatureArray + ligatureAttachOffset);
+    le_int32 componentCount = SWAPW(ligatureAttachTable->componentCount);
+    le_int32 component = ligatureIterator.getMarkComponent(markPosition);
+
+    if (component >= componentCount) {
+        // should really just bail at this point...
+        component = componentCount - 1;
+    }
+
+    const ComponentRecord *componentRecord = &ligatureAttachTable->componentRecordArray[component * mcCount];
+    Offset anchorTableOffset = SWAPW(componentRecord->ligatureAnchorTableOffsetArray[markClass]);
+    const AnchorTable *anchorTable = (const AnchorTable *) ((char *) ligatureAttachTable + anchorTableOffset);
+    LEPoint ligatureAnchor, markAdvance, pixels;
+
+    anchorTable->getAnchor(ligatureGlyph, fontInstance, ligatureAnchor);
+
+    fontInstance->getGlyphAdvance(markGlyph, pixels);
+    fontInstance->pixelsToUnits(pixels, markAdvance);
+
+    float anchorDiffX = ligatureAnchor.fX - markAnchor.fX;
+    float anchorDiffY = ligatureAnchor.fY - markAnchor.fY;
+
+    glyphIterator->setCurrGlyphBaseOffset(ligatureIterator.getCurrStreamPosition());
+
+    if (glyphIterator->isRightToLeft()) {
+        glyphIterator->setCurrGlyphPositionAdjustment(anchorDiffX, anchorDiffY, -markAdvance.fX, -markAdvance.fY);
+    } else {
+        LEPoint ligatureAdvance;
+
+        fontInstance->getGlyphAdvance(ligatureGlyph, pixels);
+        fontInstance->pixelsToUnits(pixels, ligatureAdvance);
+
+        glyphIterator->setCurrGlyphPositionAdjustment(anchorDiffX - ligatureAdvance.fX, anchorDiffY - ligatureAdvance.fY, -markAdvance.fX, -markAdvance.fY);
+    }
+
+    return 1;
+}
+
+U_NAMESPACE_END