C++ SkDescriptor::addEntry方法代码示例

SkScalerContext* SkFontHost::CreateFallbackScalerContext(const SkScalerContext::Rec& rec) {

    const LOGFONT* face = get_default_font();



    SkAutoDescriptor    ad(sizeof(rec) + sizeof(face) + SkDescriptor::ComputeOverhead(2));

    SkDescriptor*       desc = ad.getDesc();



    desc->init();

    desc->addEntry(kRec_SkDescriptorTag, sizeof(rec), &rec);

    desc->addEntry(kTypeface_SkDescriptorTag, sizeof(face), &face);

    desc->computeChecksum();



    return SkFontHost::CreateScalerContext(desc);

}

// Return the context associated with the next logical typeface, or NULL if
// there are no more entries in the fallback chain.
SkScalerContext* SkScalerContext::allocNextContext() const {
#ifdef SK_BUILD_FOR_ANDROID
    SkTypeface* newFace = SkAndroidNextLogicalTypeface(fRec.fFontID,
                                                       fRec.fOrigFontID,
                                                       fPaintOptionsAndroid);
    if (0 == newFace) {
        return NULL;
    }

    SkAutoTUnref<SkTypeface> aur(newFace);
    uint32_t newFontID = newFace->uniqueID();

    SkOrderedWriteBuffer androidBuffer(128);
    fPaintOptionsAndroid.flatten(androidBuffer);

    SkAutoDescriptor    ad(sizeof(fRec) + androidBuffer.size() + SkDescriptor::ComputeOverhead(2));
    SkDescriptor*       desc = ad.getDesc();

    desc->init();
    SkScalerContext::Rec* newRec =
    (SkScalerContext::Rec*)desc->addEntry(kRec_SkDescriptorTag,
                                          sizeof(fRec), &fRec);
    androidBuffer.writeToMemory(desc->addEntry(kAndroidOpts_SkDescriptorTag,
                                               androidBuffer.size(), NULL));

    newRec->fFontID = newFontID;
    desc->computeChecksum();

    return newFace->createScalerContext(desc);
#else
    return NULL;
#endif
}

GrPathRange* GrPathRendering::createGlyphs(const SkTypeface* typeface,
                                           const SkScalerContextEffects& effects,
                                           const SkDescriptor* desc,
                                           const GrStyle& style) {
    if (nullptr == typeface) {
        typeface = SkTypeface::GetDefaultTypeface();
        SkASSERT(nullptr != typeface);
    }

    if (desc) {
        SkAutoTUnref<GlyphGenerator> generator(new GlyphGenerator(*typeface, effects, *desc));
        return this->createPathRange(generator, style);
    }

    SkScalerContextRec rec;
    memset(&rec, 0, sizeof(rec));
    rec.fFontID = typeface->uniqueID();
    rec.fTextSize = SkPaint::kCanonicalTextSizeForPaths;
    rec.fPreScaleX = rec.fPost2x2[0][0] = rec.fPost2x2[1][1] = SK_Scalar1;
    // Don't bake stroke information into the glyphs, we'll let the GPU do the stroking.

    SkAutoDescriptor ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
    SkDescriptor*    genericDesc = ad.getDesc();

    genericDesc->init();
    genericDesc->addEntry(kRec_SkDescriptorTag, sizeof(rec), &rec);
    genericDesc->computeChecksum();
    
    // No effects, so we make a dummy struct
    SkScalerContextEffects noEffects;

    SkAutoTUnref<GlyphGenerator> generator(new GlyphGenerator(*typeface, noEffects, *genericDesc));
    return this->createPathRange(generator, style);
}

bool SkTypeface::onComputeBounds(SkRect* bounds) const {
    // we use a big size to ensure lots of significant bits from the scalercontext.
    // then we scale back down to return our final answer (at 1-pt)
    const SkScalar textSize = 2048;
    const SkScalar invTextSize = 1 / textSize;

    SkPaint paint;
    paint.setTypeface(const_cast<SkTypeface*>(this));
    paint.setTextSize(textSize);
    paint.setLinearText(true);

    SkScalerContext::Rec rec;
    SkScalerContext::MakeRec(paint, NULL, NULL, &rec);

    SkAutoDescriptor ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
    SkDescriptor*    desc = ad.getDesc();
    desc->init();
    desc->addEntry(kRec_SkDescriptorTag, sizeof(rec), &rec);

    SkAutoTDelete<SkScalerContext> ctx(this->createScalerContext(desc, true));
    if (ctx.get()) {
        SkPaint::FontMetrics fm;
        ctx->getFontMetrics(&fm);
        bounds->set(fm.fXMin * invTextSize, fm.fTop * invTextSize,
                    fm.fXMax * invTextSize, fm.fBottom * invTextSize);
        return true;
    }
    return false;
}

static SkScalerContext* allocNextContext(const SkScalerContext::Rec& rec) {
    // fonthost will determine the next possible font to search, based
    // on the current font in fRec. It will return NULL if ctx is our
    // last font that can be searched (i.e. ultimate fallback font)
#ifdef SK_BUILD_FOR_ANDROID
        // On Android, pass entire rec structure so that clients can change fallback behavior
        uint32_t newFontID = SkFontHost::NextLogicalFont(rec);
#else
    uint32_t newFontID = SkFontHost::NextLogicalFont(rec.fFontID, rec.fOrigFontID);
#endif

    if (0 == newFontID) {
        return NULL;
    }

    SkAutoDescriptor    ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
    SkDescriptor*       desc = ad.getDesc();

    desc->init();
    SkScalerContext::Rec* newRec =
    (SkScalerContext::Rec*)desc->addEntry(kRec_SkDescriptorTag,
                                          sizeof(rec), &rec);
    newRec->fFontID = newFontID;
    desc->computeChecksum();

    return SkFontHost::CreateScalerContext(desc);
}

SkGScalerContext::SkGScalerContext(SkGTypeface* face, const SkDescriptor* desc)
        : SkScalerContext(face, desc)
        , fFace(face)
{

    size_t  descSize = SkDescriptor::ComputeOverhead(1) + sizeof(SkScalerContext::Rec);
    SkAutoDescriptor ad(descSize);
    SkDescriptor*    newDesc = ad.getDesc();

    newDesc->init();
    void* entry = newDesc->addEntry(kRec_SkDescriptorTag,
                                    sizeof(SkScalerContext::Rec), &fRec);
    {
        SkScalerContext::Rec* rec = (SkScalerContext::Rec*)entry;
        rec->fTextSize = STD_SIZE;
        rec->fPreScaleX = SK_Scalar1;
        rec->fPreSkewX = 0;
        rec->fPost2x2[0][0] = rec->fPost2x2[1][1] = SK_Scalar1;
        rec->fPost2x2[1][0] = rec->fPost2x2[0][1] = 0;
    }
    SkASSERT(descSize == newDesc->getLength());
    newDesc->computeChecksum();

    fProxy = face->proxy()->createScalerContext(newDesc);

    fRec.getSingleMatrix(&fMatrix);
    fMatrix.preScale(SK_Scalar1 / STD_SIZE, SK_Scalar1 / STD_SIZE);
}

static SkScalerContext* allocNextContext(const SkScalerContext::Rec& rec) {
    // fonthost will determine the next possible font to search, based
    // on the current font in fRec. It will return NULL if ctx is our
    // last font that can be searched (i.e. ultimate fallback font)
    uint32_t newFontID = SkFontHost::NextLogicalFont(rec.fFontID, rec.fOrigFontID);
    if (0 == newFontID) {
        return NULL;
    }

    SkAutoDescriptor    ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
    SkDescriptor*       desc = ad.getDesc();

    desc->init();
    SkScalerContext::Rec* newRec =
    (SkScalerContext::Rec*)desc->addEntry(kRec_SkDescriptorTag,
                                          sizeof(rec), &rec);
    newRec->fFontID = newFontID;
    desc->computeChecksum();

    return SkFontHost::CreateScalerContext(desc);
}