GlyphPageTreeNodeSkia.cpp   [plain text]

/*
 * Copyright (c) 2008, 2009 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 * 
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 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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#include "config.h"
#include "GlyphPageTreeNode.h"

#include "Font.h"
#include "HarfBuzzSkia.h"
#include "SimpleFontData.h"

#include "SkTemplates.h"
#include "SkPaint.h"
#include "SkUtils.h"

extern "C" {
#include "harfbuzz-shaper.h"
}

namespace WebCore {

static int substituteWithVerticalGlyphs(const SimpleFontData* fontData, uint16_t* glyphs, unsigned bufferLength)
{
    HB_FaceRec_* hbFace = fontData->platformData().harfbuzzFace()->face();
    if (!hbFace->gsub) {
        // if there is no GSUB table, treat it as not covered
        return 0Xffff;
    }

    HB_Buffer buffer;
    hb_buffer_new(&buffer);
    for (unsigned i = 0; i < bufferLength; ++i)
        hb_buffer_add_glyph(buffer, glyphs[i], 0, i);

    HB_UShort scriptIndex;
    HB_UShort featureIndex;

    HB_GSUB_Select_Script(hbFace->gsub, HB_MAKE_TAG('D', 'F', 'L', 'T'), &scriptIndex);
    HB_GSUB_Select_Feature(hbFace->gsub, HB_MAKE_TAG('v', 'e', 'r', 't'), scriptIndex, 0xffff, &featureIndex);
    HB_GSUB_Add_Feature(hbFace->gsub, featureIndex, 1);
    HB_GSUB_Select_Feature(hbFace->gsub, HB_MAKE_TAG('v', 'r', 't', '2'), scriptIndex, 0xffff, &featureIndex);
    HB_GSUB_Add_Feature(hbFace->gsub, featureIndex, 1);

    int error = HB_GSUB_Apply_String(hbFace->gsub, buffer);
    if (!error) {
        for (unsigned i = 0; i < bufferLength; ++i)
            glyphs[i] = static_cast<Glyph>(buffer->out_string[i].gindex);
    }
    return error;
}

bool GlyphPage::fill(unsigned offset, unsigned length, UChar* buffer, unsigned bufferLength, const SimpleFontData* fontData)
{
    if (SkUTF16_IsHighSurrogate(buffer[bufferLength-1])) {
        SkDebugf("%s last char is high-surrogate", __FUNCTION__);
        return false;
    }
    
    SkPaint paint;
    fontData->platformData().setupPaint(&paint);
    paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
    
    SkAutoSTMalloc <GlyphPage::size, uint16_t> glyphStorage(length);
    uint16_t* glyphs = glyphStorage.get();
    // textToGlyphs takes a byte count, not a glyph count so we multiply by two.
    unsigned count = paint.textToGlyphs(buffer, bufferLength * 2, glyphs);
    if (count != length) {
        SkDebugf("%s count != length\n", __FUNCTION__);
        return false;
    }

    if (fontData->hasVerticalGlyphs()) {
        for (unsigned i = 0; i < bufferLength; ++i) {
            if (!Font::isCJKIdeograph(buffer[i])) {
                substituteWithVerticalGlyphs(fontData, glyphs, length);
                break;
            }
        }
    }

    unsigned allGlyphs = 0; // track if any of the glyphIDs are non-zero
    for (unsigned i = 0; i < length; i++) {
        setGlyphDataForIndex(offset + i, glyphs[i], glyphs[i] ? fontData : NULL);
        allGlyphs |= glyphs[i];
    }

    return allGlyphs != 0;
}

}  // namespace WebCore