bool FilterEffectRendererHelper::beginFilterEffect()
{
ASSERT(m_renderLayer);
FilterEffectRenderer* filter = m_renderLayer->filterRenderer();
filter->allocateBackingStoreIfNeeded();
// Paint into the context that represents the SourceGraphic of the filter.
GraphicsContext* sourceGraphicsContext = filter->inputContext();
if (!sourceGraphicsContext || filter->filterRegion().isEmpty() || ImageBuffer::sizeNeedsClamping(filter->filterRegion().size())) {
// Disable the filters and continue.
m_haveFilterEffect = false;
return false;
}
// Translate the context so that the contents of the layer is captuterd in the offscreen memory buffer.
sourceGraphicsContext->save();
sourceGraphicsContext->translate(-m_paintOffset.x(), -m_paintOffset.y());
sourceGraphicsContext->clearRect(m_repaintRect);
sourceGraphicsContext->clip(m_repaintRect);
m_startedFilterEffect = true;
return true;
}
GraphicsContext* FilterEffectRendererHelper::beginFilterEffect(GraphicsContext* oldContext)
{
ASSERT(m_renderLayer);
FilterEffectRenderer* filter = m_renderLayer->filterRenderer();
filter->allocateBackingStoreIfNeeded();
// Paint into the context that represents the SourceGraphic of the filter.
GraphicsContext* sourceGraphicsContext = filter->inputContext();
if (!sourceGraphicsContext || !isFilterSizeValid(filter->filterRegion())) {
// Disable the filters and continue.
m_haveFilterEffect = false;
return oldContext;
}
m_savedGraphicsContext = oldContext;
// Translate the context so that the contents of the layer is captuterd in the offscreen memory buffer.
sourceGraphicsContext->save();
sourceGraphicsContext->translate(-m_paintOffset.x(), -m_paintOffset.y());
sourceGraphicsContext->clearRect(m_repaintRect);
sourceGraphicsContext->clip(m_repaintRect);
return sourceGraphicsContext;
}