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.set(sourceGraphic.release());
filterData->savedContext = context;
context = sourceGraphicContext;
m_filter.set(object, filterData.release());
return true;
}
