PassRefPtr<FilterEffect> ReferenceFilterBuilder::build(Filter* parentFilter, RenderObject* renderer, FilterEffect* previousEffect, const ReferenceFilterOperation* filterOperation)
{
if (!renderer)
return 0;
Document* document = &renderer->document();
if (DocumentResourceReference* documentResourceRef = documentResourceReference(filterOperation)) {
DocumentResource* cachedSVGDocument = documentResourceRef->document();
// If we have an SVG document, this is an external reference. Otherwise
// we look up the referenced node in the current document.
if (cachedSVGDocument)
document = cachedSVGDocument->document();
}
if (!document)
return 0;
Element* filter = document->getElementById(filterOperation->fragment());
if (!filter) {
// Although we did not find the referenced filter, it might exist later
// in the document
document->accessSVGExtensions()->addPendingResource(filterOperation->fragment(), toElement(renderer->node()));
return 0;
}
if (!filter->isSVGElement() || !filter->hasTagName(SVGNames::filterTag))
return 0;
SVGFilterElement* filterElement = toSVGFilterElement(toSVGElement(filter));
// FIXME: Figure out what to do with SourceAlpha. Right now, we're
// using the alpha of the original input layer, which is obviously
// wrong. We should probably be extracting the alpha from the
// previousEffect, but this requires some more processing.
// This may need a spec clarification.
RefPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(previousEffect, SourceAlpha::create(parentFilter));
ColorSpace filterColorSpace = ColorSpaceDeviceRGB;
bool useFilterColorSpace = getSVGElementColorSpace(filterElement, filterColorSpace);
for (Node* node = filterElement->firstChild(); node; node = node->nextSibling()) {
if (!node->isSVGElement())
continue;
SVGElement* element = toSVGElement(node);
if (!element->isFilterEffect())
continue;
SVGFilterPrimitiveStandardAttributes* effectElement = static_cast<SVGFilterPrimitiveStandardAttributes*>(element);
RefPtr<FilterEffect> effect = effectElement->build(builder.get(), parentFilter);
if (!effect)
continue;
effectElement->setStandardAttributes(effect.get());
effect->setEffectBoundaries(SVGLengthContext::resolveRectangle<SVGFilterPrimitiveStandardAttributes>(effectElement, filterElement->primitiveUnitsCurrentValue(), parentFilter->sourceImageRect()));
ColorSpace colorSpace = filterColorSpace;
if (useFilterColorSpace || getSVGElementColorSpace(effectElement, colorSpace))
effect->setOperatingColorSpace(colorSpace);
builder->add(effectElement->resultCurrentValue(), effect);
}
return builder->lastEffect();
}
