C++ SkGlyph::computeImageSize方法代码示例

void SkRandomScalerContext::generateImage(const SkGlyph& glyph) {
    SkMask::Format format = (SkMask::Format)glyph.fMaskFormat;
    switch (glyph.getGlyphID() % 4) {
        case 0:
            format = SkMask::kLCD16_Format;
            break;
        case 1:
            format = SkMask::kA8_Format;
            break;
        case 2:
            format = SkMask::kARGB32_Format;
            break;
        case 3:
            format = SkMask::kBW_Format;
            break;
    }
    const_cast<SkGlyph&>(glyph).fMaskFormat = format;

    // if the format is ARGB, we just draw the glyph from path ourselves.  Otherwise, we force
    // our proxy context to generate the image from paths.
    if (!fFakeIt) {
        if (SkMask::kARGB32_Format == glyph.fMaskFormat) {
            SkPath path;
            fProxy->getPath(glyph, &path);

            SkBitmap bm;
            bm.installPixels(SkImageInfo::MakeN32Premul(glyph.fWidth, glyph.fHeight),
                             glyph.fImage, glyph.rowBytes());
            bm.eraseColor(0);

            SkCanvas canvas(bm);
            canvas.translate(-SkIntToScalar(glyph.fLeft),
                             -SkIntToScalar(glyph.fTop));
            canvas.drawPath(path, fFace->paint());
        } else {
            fProxy->forceGenerateImageFromPath();
            fProxy->getImage(glyph);
            fProxy->forceOffGenerateImageFromPath();
        }
    } else {
        sk_bzero(glyph.fImage, glyph.computeImageSize());
    }
}

void RandomScalerContext::generateImage(const SkGlyph& glyph) {
    // TODO: can force down but not up
    /*
    SkMask::Format format = (SkMask::Format)glyph.fMaskFormat;
    switch (glyph.getGlyphID() % 4) {
        case 0: format = SkMask::kLCD16_Format; break;
        case 1: format = SkMask::kA8_Format; break;
        case 2: format = SkMask::kARGB32_Format; break;
        case 3: format = SkMask::kBW_Format; break;
    }
    const_cast<SkGlyph&>(glyph).fMaskFormat = format;
    */

    if (fFakeIt) {
        sk_bzero(glyph.fImage, glyph.computeImageSize());
        return;
    }

    if (SkMask::kARGB32_Format != glyph.fMaskFormat) {
        fProxy->getImage(glyph);
        return;
    }

    // If the format is ARGB, just draw the glyph from path.
    SkPath path;
    if (!fProxy->getPath(glyph.getPackedID(), &path)) {
        fProxy->getImage(glyph);
        return;
    }

    SkBitmap bm;
    bm.installPixels(SkImageInfo::MakeN32Premul(glyph.fWidth, glyph.fHeight),
                     glyph.fImage,
                     glyph.rowBytes());
    bm.eraseColor(0);

    SkCanvas canvas(bm);
    canvas.translate(-SkIntToScalar(glyph.fLeft), -SkIntToScalar(glyph.fTop));
    canvas.drawPath(path, this->getRandomTypeface()->paint());
}

void SkScalerContext::getImage(const SkGlyph& origGlyph) {
    const SkGlyph*  glyph = &origGlyph;
    SkGlyph         tmpGlyph;

    // in case we need to call generateImage on a mask-format that is different
    // (i.e. larger) than what our caller allocated by looking at origGlyph.
    SkAutoMalloc tmpGlyphImageStorage;

    // If we are going to draw-from-path, then we cannot generate color, since
    // the path only makes a mask. This case should have been caught up in
    // generateMetrics().
    SkASSERT(!fGenerateImageFromPath ||
             SkMask::kARGB32_Format != origGlyph.fMaskFormat);

    if (fMaskFilter) {   // restore the prefilter bounds
        tmpGlyph.initGlyphIdFrom(origGlyph);

        // need the original bounds, sans our maskfilter
        SkMaskFilter* mf = fMaskFilter;
        fMaskFilter = nullptr;             // temp disable
        this->getMetrics(&tmpGlyph);
        fMaskFilter = mf;               // restore

        // we need the prefilter bounds to be <= filter bounds
        SkASSERT(tmpGlyph.fWidth <= origGlyph.fWidth);
        SkASSERT(tmpGlyph.fHeight <= origGlyph.fHeight);

        if (tmpGlyph.fMaskFormat == origGlyph.fMaskFormat) {
            tmpGlyph.fImage = origGlyph.fImage;
        } else {
            tmpGlyphImageStorage.reset(tmpGlyph.computeImageSize());
            tmpGlyph.fImage = tmpGlyphImageStorage.get();
        }
        glyph = &tmpGlyph;
    }

    if (fGenerateImageFromPath) {
        SkPath      devPath, fillPath;
        SkMatrix    fillToDevMatrix;
        SkMask      mask;

        this->internalGetPath(*glyph, &fillPath, &devPath, &fillToDevMatrix);
        glyph->toMask(&mask);

        if (fRasterizer) {
            mask.fFormat = SkMask::kA8_Format;
            sk_bzero(glyph->fImage, mask.computeImageSize());

            if (!fRasterizer->rasterize(fillPath, fillToDevMatrix, nullptr,
                                        fMaskFilter, &mask,
                                        SkMask::kJustRenderImage_CreateMode)) {
                return;
            }
            if (fPreBlend.isApplicable()) {
                applyLUTToA8Mask(mask, fPreBlend.fG);
            }
        } else {
            SkASSERT(SkMask::kARGB32_Format != mask.fFormat);
            generateMask(mask, devPath, fPreBlend);
        }
    } else {
        generateImage(*glyph);
    }

    if (fMaskFilter) {
        SkMask      srcM, dstM;
        SkMatrix    matrix;

        // the src glyph image shouldn't be 3D
        SkASSERT(SkMask::k3D_Format != glyph->fMaskFormat);

        SkAutoSMalloc<32*32> a8storage;
        glyph->toMask(&srcM);
        if (SkMask::kARGB32_Format == srcM.fFormat) {
            // now we need to extract the alpha-channel from the glyph's image
            // and copy it into a temp buffer, and then point srcM at that temp.
            srcM.fFormat = SkMask::kA8_Format;
            srcM.fRowBytes = SkAlign4(srcM.fBounds.width());
            size_t size = srcM.computeImageSize();
            a8storage.reset(size);
            srcM.fImage = (uint8_t*)a8storage.get();
            extract_alpha(srcM,
                          (const SkPMColor*)glyph->fImage, glyph->rowBytes());
        }

        fRec.getMatrixFrom2x2(&matrix);

        if (fMaskFilter->filterMask(&dstM, srcM, matrix, nullptr)) {
            int width = SkFastMin32(origGlyph.fWidth, dstM.fBounds.width());
            int height = SkFastMin32(origGlyph.fHeight, dstM.fBounds.height());
            int dstRB = origGlyph.rowBytes();
            int srcRB = dstM.fRowBytes;

            const uint8_t* src = (const uint8_t*)dstM.fImage;
            uint8_t* dst = (uint8_t*)origGlyph.fImage;

            if (SkMask::k3D_Format == dstM.fFormat) {
                // we have to copy 3 times as much
                height *= 3;
            }
//.........这里部分代码省略.........