C++ SVGFilterElement::filterResY方法代码示例

bool RenderSVGResourceFilter::applyResource(RenderObject* object, RenderStyle*, GraphicsContext*& context, unsigned short resourceMode)
{
    ASSERT(object);
    ASSERT(context);
    ASSERT_UNUSED(resourceMode, resourceMode == ApplyToDefaultMode);

    // Returning false here, to avoid drawings onto the context. We just want to
    // draw the stored filter output, not the unfiltered object as well.
    if (m_filter.contains(object)) {
        FilterData* filterData = m_filter.get(object);
        if (filterData->builded)
            return false;

        delete m_filter.take(object); // Oops, have to rebuild, go through normal code path
    }

    OwnPtr<FilterData> filterData(adoptPtr(new FilterData));
    FloatRect targetBoundingBox = object->objectBoundingBox();

    SVGFilterElement* filterElement = static_cast<SVGFilterElement*>(node());
    filterData->boundaries = SVGLengthContext::resolveRectangle<SVGFilterElement>(filterElement, filterElement->filterUnits(), targetBoundingBox);
    if (filterData->boundaries.isEmpty())
        return false;

    // Determine absolute transformation matrix for filter. 
    AffineTransform absoluteTransform;
    SVGImageBufferTools::calculateTransformationToOutermostSVGCoordinateSystem(object, absoluteTransform);
    if (!absoluteTransform.isInvertible())
        return false;

    // Eliminate shear of the absolute transformation matrix, to be able to produce unsheared tile images for feTile.
    filterData->shearFreeAbsoluteTransform = AffineTransform(absoluteTransform.xScale(), 0, 0, absoluteTransform.yScale(), 0, 0);

    // Determine absolute boundaries of the filter and the drawing region.
    FloatRect absoluteFilterBoundaries = filterData->shearFreeAbsoluteTransform.mapRect(filterData->boundaries);
    FloatRect drawingRegion = object->strokeBoundingBox();
    drawingRegion.intersect(filterData->boundaries);
    FloatRect absoluteDrawingRegion = filterData->shearFreeAbsoluteTransform.mapRect(drawingRegion);

    // Create the SVGFilter object.
    bool primitiveBoundingBoxMode = filterElement->primitiveUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;
    filterData->filter = SVGFilter::create(filterData->shearFreeAbsoluteTransform, absoluteDrawingRegion, targetBoundingBox, filterData->boundaries, primitiveBoundingBoxMode);

    // Create all relevant filter primitives.
    filterData->builder = buildPrimitives(filterData->filter.get());
    if (!filterData->builder)
        return false;

    // Calculate the scale factor for the use of filterRes.
    // Also see http://www.w3.org/TR/SVG/filters.html#FilterEffectsRegion
    FloatSize scale(1, 1);
    if (filterElement->hasAttribute(SVGNames::filterResAttr)) {
        scale.setWidth(filterElement->filterResX() / absoluteFilterBoundaries.width());
        scale.setHeight(filterElement->filterResY() / absoluteFilterBoundaries.height());
    }

    if (scale.isEmpty())
        return false;

    // Determine scale factor for filter. The size of intermediate ImageBuffers shouldn't be bigger than kMaxFilterSize.
    FloatRect tempSourceRect = absoluteDrawingRegion;
    tempSourceRect.scale(scale.width(), scale.height());
    fitsInMaximumImageSize(tempSourceRect.size(), scale);

    // Set the scale level in SVGFilter.
    filterData->filter->setFilterResolution(scale);

    FilterEffect* lastEffect = filterData->builder->lastEffect();
    if (!lastEffect)
        return false;

    RenderSVGResourceFilterPrimitive::determineFilterPrimitiveSubregion(lastEffect);
    FloatRect subRegion = lastEffect->maxEffectRect();
    // At least one FilterEffect has a too big image size,
    // recalculate the effect sizes with new scale factors.
    if (!fitsInMaximumImageSize(subRegion.size(), scale)) {
        filterData->filter->setFilterResolution(scale);
        RenderSVGResourceFilterPrimitive::determineFilterPrimitiveSubregion(lastEffect);
    }

    // If the drawingRegion is empty, we have something like <g filter=".."/>.
    // Even if the target objectBoundingBox() is empty, we still have to draw the last effect result image in postApplyResource.
    if (drawingRegion.isEmpty()) {
        ASSERT(!m_filter.contains(object));
        filterData->savedContext = context;
        m_filter.set(object, filterData.leakPtr());
        return false;
    }

    // Change the coordinate transformation applied to the filtered element to reflect the resolution of the filter.
    AffineTransform effectiveTransform;
    effectiveTransform.scale(scale.width(), scale.height());
    effectiveTransform.multiply(filterData->shearFreeAbsoluteTransform);

    OwnPtr<ImageBuffer> sourceGraphic;
    RenderingMode renderingMode = object->document()->page()->settings()->acceleratedFiltersEnabled() ? Accelerated : Unaccelerated;
    if (!SVGImageBufferTools::createImageBuffer(drawingRegion, effectiveTransform, sourceGraphic, ColorSpaceLinearRGB, renderingMode)) {
        ASSERT(!m_filter.contains(object));
        filterData->savedContext = context;
        m_filter.set(object, filterData.leakPtr());
//.........这里部分代码省略.........

bool RenderSVGResourceFilter::applyResource(RenderObject* object, RenderStyle*, GraphicsContext*& context, unsigned short resourceMode)
{
    ASSERT(object);
    ASSERT(context);
#ifndef NDEBUG
    ASSERT(resourceMode == ApplyToDefaultMode);
#else
    UNUSED_PARAM(resourceMode);
#endif

    // Returning false here, to avoid drawings onto the context. We just want to
    // draw the stored filter output, not the unfiltered object as well.
    if (m_filter.contains(object)) {
        FilterData* filterData = m_filter.get(object);
        if (filterData->builded)
            return false;

        delete m_filter.take(object); // Oops, have to rebuild, go through normal code path
    }

    OwnPtr<FilterData> filterData(new FilterData);
    filterData->builder = buildPrimitives();
    if (!filterData->builder)
        return false;

    FloatRect paintRect = object->strokeBoundingBox();

    // Calculate the scale factor for the use of filterRes.
    // Also see http://www.w3.org/TR/SVG/filters.html#FilterEffectsRegion
    SVGFilterElement* filterElement = static_cast<SVGFilterElement*>(node());
    filterData->boundaries = filterElement->filterBoundingBox(object->objectBoundingBox());
    if (filterData->boundaries.isEmpty())
        return false;

    FloatSize scale(1.0f, 1.0f);
    if (filterElement->hasAttribute(SVGNames::filterResAttr)) {
        scale.setWidth(filterElement->filterResX() / filterData->boundaries.width());
        scale.setHeight(filterElement->filterResY() / filterData->boundaries.height());
    }

    if (scale.isEmpty())
        return false;

    // clip sourceImage to filterRegion
    FloatRect clippedSourceRect = paintRect;
    clippedSourceRect.intersect(filterData->boundaries);

    // scale filter size to filterRes
    FloatRect tempSourceRect = clippedSourceRect;

    // scale to big sourceImage size to kMaxFilterSize
    tempSourceRect.scale(scale.width(), scale.height());
    fitsInMaximumImageSize(tempSourceRect.size(), scale);

    // prepare Filters
    bool primitiveBoundingBoxMode = filterElement->primitiveUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;
    filterData->filter = SVGFilter::create(paintRect, filterData->boundaries, primitiveBoundingBoxMode);
    filterData->filter->setFilterResolution(scale);

    FilterEffect* lastEffect = filterData->builder->lastEffect();
    if (!lastEffect)
        return false;
    
    lastEffect->calculateEffectRect(filterData->filter.get());
    // At least one FilterEffect has a too big image size,
    // recalculate the effect sizes with new scale factors.
    if (!fitsInMaximumImageSize(filterData->filter->maxImageSize(), scale)) {
        filterData->filter->setFilterResolution(scale);
        lastEffect->calculateEffectRect(filterData->filter.get());
    }

    clippedSourceRect.scale(scale.width(), scale.height());

    // Draw the content of the current element and it's childs to a imageBuffer to get the SourceGraphic.
    // The size of the SourceGraphic is clipped to the size of the filterRegion.
    IntRect bufferRect = enclosingIntRect(clippedSourceRect);
    OwnPtr<ImageBuffer> sourceGraphic(ImageBuffer::create(bufferRect.size(), LinearRGB));
    
    if (!sourceGraphic.get())
        return false;

    GraphicsContext* sourceGraphicContext = sourceGraphic->context();
    sourceGraphicContext->translate(-clippedSourceRect.x(), -clippedSourceRect.y());
    sourceGraphicContext->scale(scale);
    sourceGraphicContext->clearRect(FloatRect(FloatPoint(), paintRect.size()));
    filterData->sourceGraphicBuffer = sourceGraphic.release();
    filterData->savedContext = context;

    context = sourceGraphicContext;

    ASSERT(!m_filter.contains(object));
    m_filter.set(object, filterData.leakPtr());

    return true;
}