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

bool RenderSVGResourceFilter::prepareEffect(RenderObject* object, GraphicsContext*& context)
{
    ASSERT(object);
    ASSERT(context);

    clearInvalidationMask();

    if (m_filter.contains(object)) {
        FilterData* filterData = m_filter.get(object);
        if (filterData->state == FilterData::PaintingSource)
            filterData->state = FilterData::CycleDetected;
        return false; // Already built, or we're in a cycle. Regardless, just do nothing more now.
    }

    OwnPtrWillBeRawPtr<FilterData> filterData = FilterData::create();
    FloatRect targetBoundingBox = object->objectBoundingBox();

    SVGFilterElement* filterElement = toSVGFilterElement(element());
    filterData->boundaries = SVGLengthContext::resolveRectangle<SVGFilterElement>(filterElement, filterElement->filterUnits()->currentValue()->enumValue(), targetBoundingBox);
    if (filterData->boundaries.isEmpty())
        return false;

    // Create the SVGFilter object.
    FloatRect drawingRegion = object->strokeBoundingBox();
    drawingRegion.intersect(filterData->boundaries);
    bool primitiveBoundingBoxMode = filterElement->primitiveUnits()->currentValue()->enumValue() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;
    filterData->filter = SVGFilter::create(enclosingIntRect(drawingRegion), targetBoundingBox, filterData->boundaries, primitiveBoundingBoxMode);

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

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

    lastEffect->determineFilterPrimitiveSubregion(ClipToFilterRegion);

    FilterData* data = filterData.get();
    m_filter.set(object, filterData.release());
    beginDeferredFilter(context, data);
    return true;
}

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.........

GraphicsContext* SVGFilterPainter::prepareEffect(const LayoutObject& object, SVGFilterRecordingContext& recordingContext)
{
    m_filter.clearInvalidationMask();

    if (FilterData* filterData = m_filter.getFilterDataForLayoutObject(&object)) {
        // If the filterData already exists we do not need to record the content
        // to be filtered. This can occur if the content was previously recorded
        // or we are in a cycle.
        if (filterData->m_state == FilterData::PaintingFilter)
            filterData->m_state = FilterData::PaintingFilterCycleDetected;

        if (filterData->m_state == FilterData::RecordingContent)
            filterData->m_state = FilterData::RecordingContentCycleDetected;

        return nullptr;
    }

    OwnPtrWillBeRawPtr<FilterData> filterData = FilterData::create();
    FloatRect referenceBox = object.objectBoundingBox();

    SVGFilterElement* filterElement = toSVGFilterElement(m_filter.element());
    FloatRect filterRegion = SVGLengthContext::resolveRectangle<SVGFilterElement>(filterElement, filterElement->filterUnits()->currentValue()->enumValue(), referenceBox);
    if (filterRegion.isEmpty())
        return nullptr;

    // Create the SVGFilter object.
    bool primitiveBoundingBoxMode = filterElement->primitiveUnits()->currentValue()->enumValue() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;
    Filter::UnitScaling unitScaling = primitiveBoundingBoxMode ? Filter::BoundingBox : Filter::UserSpace;
    filterData->filter = Filter::create(referenceBox, filterRegion, 1, unitScaling);
    filterData->nodeMap = SVGFilterGraphNodeMap::create();

    IntRect sourceRegion = enclosingIntRect(intersection(filterRegion, object.strokeBoundingBox()));
    filterData->filter->sourceGraphic()->setSourceRect(sourceRegion);

    // Create all relevant filter primitives.
    SVGFilterBuilder builder(filterData->filter->sourceGraphic(), filterData->nodeMap.get());
    builder.buildGraph(filterData->filter.get(), *filterElement, referenceBox);

    FilterEffect* lastEffect = builder.lastEffect();
    if (!lastEffect)
        return nullptr;

    lastEffect->determineFilterPrimitiveSubregion(ClipToFilterRegion);
    filterData->filter->setLastEffect(lastEffect);

    FilterData* data = filterData.get();
    // TODO(pdr): Can this be moved out of painter?
    m_filter.setFilterDataForLayoutObject(const_cast<LayoutObject*>(&object), filterData.release());
    return recordingContext.beginContent(data);
}