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 

    19 LEGlyphID MarkToLigaturePositioningSubtable::findLigatureGlyph(GlyphIterator *glyphIterator) const

    20 {

    21     if (glyphIterator->prev()) {

    22         return glyphIterator->getCurrGlyphID();

    23     }

    24 

    25     return 0xFFFF;

    26 }

    27 

    28 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