static PassRefPtr<TransformPaintPropertyNode> createScrollTranslationIfNeeded(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
{
if (!object.isBoxModelObject() || !object.hasOverflowClip())
return nullptr;
PaintLayer* layer = toLayoutBoxModelObject(object).layer();
ASSERT(layer);
DoubleSize scrollOffset = layer->scrollableArea()->scrollOffset();
if (scrollOffset.isZero() && !layer->scrollsOverflow())
return nullptr;
RefPtr<TransformPaintPropertyNode> newTransformNodeForScrollTranslation = TransformPaintPropertyNode::create(
TransformationMatrix().translate(-scrollOffset.width(), -scrollOffset.height()),
FloatPoint3D(), context.currentTransform);
context.currentTransform = newTransformNodeForScrollTranslation.get();
return newTransformNodeForScrollTranslation.release();
}
void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
{
if (!object.isBoxModelObject() || !object.hasOverflowClip())
return;
PaintLayer* layer = toLayoutBoxModelObject(object).layer();
ASSERT(layer);
DoubleSize scrollOffset = layer->getScrollableArea()->scrollOffset();
if (scrollOffset.isZero() && !layer->scrollsOverflow())
return;
RefPtr<TransformPaintPropertyNode> scrollTranslation = TransformPaintPropertyNode::create(
TransformationMatrix().translate(-scrollOffset.width(), -scrollOffset.height()),
FloatPoint3D(),
context.currentTransform);
context.currentTransform = scrollTranslation.get();
object.getMutableForPainting().ensureObjectPaintProperties().setScrollTranslation(scrollTranslation.release());
}