MarkToBasePosnSubtables.cpp revision c73f511526464f8e56c242df80552e9b0d94ae3d 
1/*
2 *
3 * (C) Copyright IBM Corp. 1998-2013 - 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
18U_NAMESPACE_BEGIN
19
20LEGlyphID MarkToBasePositioningSubtable::findBaseGlyph(GlyphIterator *glyphIterator) const
21{
22    if (glyphIterator->prev()) {
23        return glyphIterator->getCurrGlyphID();
24    }
25
26    return 0xFFFF;
27}
28
29le_int32 MarkToBasePositioningSubtable::process(const LETableReference &base, GlyphIterator *glyphIterator, const LEFontInstance *fontInstance, LEErrorCode &success) const
30{
31    LEGlyphID markGlyph = glyphIterator->getCurrGlyphID();
32    le_int32 markCoverage = getGlyphCoverage(base, (LEGlyphID) markGlyph, success);
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(base, (LEGlyphID) baseGlyph, success);
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
115U_NAMESPACE_END
116