source/layout/CursiveAttachmentSubtables.cpp

/*
 * %W% %E%
 *
 * (C) Copyright IBM Corp. 1998, 1999, 2000, 2001, 2002 - All Rights Reserved
 *
 */

#include "LETypes.h"
#include "LEFontInstance.h"
#include "OpenTypeTables.h"
#include "GlyphPositioningTables.h"
#include "CursiveAttachmentSubtables.h"
#include "AnchorTables.h"
#include "GlyphIterator.h"
#include "GlyphPositionAdjustments.h"
#include "OpenTypeUtilities.h"
#include "LESwaps.h"

U_NAMESPACE_BEGIN

le_uint32 CursiveAttachmentSubtable::process(GlyphIterator *glyphIterator, const LEFontInstance *fontInstance) const
{
    LEGlyphID glyphID       = glyphIterator->getCurrGlyphID();
    le_int32  coverageIndex = getGlyphCoverage(glyphID);
    le_uint16 eeCount       = SWAPW(entryExitCount);

    if (coverageIndex < 0 || coverageIndex >= eeCount) {
        glyphIterator->resetCursiveLastExitPoint();
        return 0;
    }

    LEPoint entryAnchor, exitAnchor, pixels;

    if (glyphIterator->hasCursiveLastExitPoint() && entryExitRecords[coverageIndex].entryAnchor != 0) {
        Offset entryOffset = SWAPW(entryExitRecords[coverageIndex].entryAnchor);

        const AnchorTable *entryAnchorTable = (const AnchorTable *) ((char *) this + entryOffset);

        entryAnchorTable->getAnchor(glyphID, fontInstance, entryAnchor);
        glyphIterator->getCursiveLastExitPoint(exitAnchor);

        float anchorDiffX        = exitAnchor.fX - entryAnchor.fX;
        float anchorDiffY        = exitAnchor.fY - entryAnchor.fY;
        float baselineAdjustment = glyphIterator->getCursiveBaselineAdjustment();

        if (glyphIterator->isRightToLeft()) {
            LEPoint secondAdvance;

            fontInstance->getGlyphAdvance(glyphID, pixels);
            fontInstance->pixelsToUnits(pixels, secondAdvance);

            glyphIterator->adjustCurrGlyphPositionAdjustment(0, anchorDiffY + baselineAdjustment, -(anchorDiffX + secondAdvance.fX), 0);
        } else {
            LEPoint firstAdvance;

            fontInstance->getGlyphAdvance(glyphIterator->getCursiveLastGlyphID(), pixels);
            fontInstance->pixelsToUnits(pixels, firstAdvance);

            glyphIterator->adjustCursiveLastGlyphPositionAdjustment(0, 0, anchorDiffX - firstAdvance.fX, 0);
            glyphIterator->adjustCurrGlyphPositionAdjustment(0, anchorDiffY + baselineAdjustment, 0, 0);
        }

        glyphIterator->setCursiveBaselineAdjustment(anchorDiffY + baselineAdjustment);
    }

    Offset exitOffset = SWAPW(entryExitRecords[coverageIndex].exitAnchor);

    if (exitOffset != 0) {
        const AnchorTable *exitAnchorTable = (const AnchorTable *) ((char *) this + exitOffset);

        exitAnchorTable->getAnchor(glyphID, fontInstance, exitAnchor);

        if (!glyphIterator->hasCursiveFirstExitPoint()) {
            glyphIterator->setCursiveFirstExitPoint();
        }

        glyphIterator->setCursiveLastExitPoint(exitAnchor);
    } else {
        /*
         * We've got a glyph which is covered but doesn't have an
         * exit point. We call setCursiveLastExitPoint just to set
         * the position of this glyph, then resetCursiveLastExitPoint
         * to do any baseline adjustments that are required for the
         * sequence of attached glyphs.
         *
         * NOTE: we don't really care about the value of
         * extiAnchor, because after we reset the last exit
         * point, it won't be used. This is a bit of a hack.
         * There should probably be a setCursiveLastExitPoint
         * call that doesn't take an anchor...
         */
        glyphIterator->setCursiveLastExitPoint(exitAnchor);
        glyphIterator->resetCursiveLastExitPoint();
    }

    return 1;
}

U_NAMESPACE_END