1 /*
2 * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved
3 *
4 */
5
6 #include "LETypes.h"
7 #include "LEFontInstance.h"
8 #include "OpenTypeTables.h"
9 #include "AnchorTables.h"
10 #include "MarkArrays.h"
11 #include "GlyphPositioningTables.h"
12 #include "AttachmentPosnSubtables.h"
13 #include "MarkToLigaturePosnSubtables.h"
14 #include "GlyphIterator.h"
15 #include "LESwaps.h"
16
17 U_NAMESPACE_BEGIN
18
findLigatureGlyph(GlyphIterator * glyphIterator) const19 LEGlyphID MarkToLigaturePositioningSubtable::findLigatureGlyph(GlyphIterator *glyphIterator) const
20 {
21 if (glyphIterator->prev()) {
22 return glyphIterator->getCurrGlyphID();
23 }
24
25 return 0xFFFF;
26 }
27
process(GlyphIterator * glyphIterator,const LEFontInstance * fontInstance) const28 le_int32 MarkToLigaturePositioningSubtable::process(GlyphIterator *glyphIterator, const LEFontInstance *fontInstance) const
29 {
30 LEGlyphID markGlyph = glyphIterator->getCurrGlyphID();
31 le_int32 markCoverage = getGlyphCoverage((LEGlyphID) markGlyph);
32
33 if (markCoverage < 0) {
34 // markGlyph isn't a covered mark glyph
35 return 0;
36 }
37
38 LEPoint markAnchor;
39 const MarkArray *markArray = (const MarkArray *) ((char *) this + SWAPW(markArrayOffset));
40 le_int32 markClass = markArray->getMarkClass(markGlyph, markCoverage, fontInstance, markAnchor);
41 le_uint16 mcCount = SWAPW(classCount);
42
43 if (markClass < 0 || markClass >= mcCount) {
44 // markGlyph isn't in the mark array or its
45 // mark class is too big. The table is mal-formed!
46 return 0;
47 }
48
49 // FIXME: we probably don't want to find a ligature before a previous base glyph...
50 GlyphIterator ligatureIterator(*glyphIterator, (le_uint16) (lfIgnoreMarks /*| lfIgnoreBaseGlyphs*/));
51 LEGlyphID ligatureGlyph = findLigatureGlyph(&ligatureIterator);
52 le_int32 ligatureCoverage = getBaseCoverage((LEGlyphID) ligatureGlyph);
53 const LigatureArray *ligatureArray = (const LigatureArray *) ((char *) this + SWAPW(baseArrayOffset));
54 le_uint16 ligatureCount = SWAPW(ligatureArray->ligatureCount);
55
56 if (ligatureCoverage < 0 || ligatureCoverage >= ligatureCount) {
57 // The ligature glyph isn't covered, or the coverage
58 // index is too big. The latter means that the
59 // table is mal-formed...
60 return 0;
61 }
62
63 le_int32 markPosition = glyphIterator->getCurrStreamPosition();
64 Offset ligatureAttachOffset = SWAPW(ligatureArray->ligatureAttachTableOffsetArray[ligatureCoverage]);
65 const LigatureAttachTable *ligatureAttachTable = (const LigatureAttachTable *) ((char *) ligatureArray + ligatureAttachOffset);
66 le_int32 componentCount = SWAPW(ligatureAttachTable->componentCount);
67 le_int32 component = ligatureIterator.getMarkComponent(markPosition);
68
69 if (component >= componentCount) {
70 // should really just bail at this point...
71 component = componentCount - 1;
72 }
73
74 const ComponentRecord *componentRecord = &ligatureAttachTable->componentRecordArray[component * mcCount];
75 Offset anchorTableOffset = SWAPW(componentRecord->ligatureAnchorTableOffsetArray[markClass]);
76 const AnchorTable *anchorTable = (const AnchorTable *) ((char *) ligatureAttachTable + anchorTableOffset);
77 LEPoint ligatureAnchor, markAdvance, pixels;
78
79 anchorTable->getAnchor(ligatureGlyph, fontInstance, ligatureAnchor);
80
81 fontInstance->getGlyphAdvance(markGlyph, pixels);
82 fontInstance->pixelsToUnits(pixels, markAdvance);
83
84 float anchorDiffX = ligatureAnchor.fX - markAnchor.fX;
85 float anchorDiffY = ligatureAnchor.fY - markAnchor.fY;
86
87 glyphIterator->setCurrGlyphBaseOffset(ligatureIterator.getCurrStreamPosition());
88
89 if (glyphIterator->isRightToLeft()) {
90 glyphIterator->setCurrGlyphPositionAdjustment(anchorDiffX, anchorDiffY, -markAdvance.fX, -markAdvance.fY);
91 } else {
92 LEPoint ligatureAdvance;
93
94 fontInstance->getGlyphAdvance(ligatureGlyph, pixels);
95 fontInstance->pixelsToUnits(pixels, ligatureAdvance);
96
97 glyphIterator->setCurrGlyphPositionAdjustment(anchorDiffX - ligatureAdvance.fX, anchorDiffY - ligatureAdvance.fY, -markAdvance.fX, -markAdvance.fY);
98 }
99
100 return 1;
101 }
102
103 U_NAMESPACE_END
104