nsIntRect
SVGFECompositeElement::ComputeTargetBBox(const nsTArray<nsIntRect>& aSourceBBoxes,
const nsSVGFilterInstance& aInstance)
{
uint16_t op = mEnumAttributes[OPERATOR].GetAnimValue();
if (op == SVG_FECOMPOSITE_OPERATOR_ARITHMETIC) {
// "arithmetic" operator can produce non-zero alpha values even where
// all input alphas are zero, so we can actually render outside the
// union of the source bboxes.
// XXX we could also check that k4 is nonzero and check for other
// cases like k1/k2 or k1/k3 zero.
return GetMaxRect();
}
if (op == SVG_FECOMPOSITE_OPERATOR_IN ||
op == SVG_FECOMPOSITE_OPERATOR_ATOP) {
// We will only draw where in2 has nonzero alpha, so it's a good
// bounding box for us
return aSourceBBoxes[1];
}
// The regular Porter-Duff operators always compute zero alpha values
// where all sources have zero alpha, so the union of their bounding
// boxes is also a bounding box for our rendering
return SVGFECompositeElementBase::ComputeTargetBBox(aSourceBBoxes, aInstance);
}
nsIntRect
SVGFEDisplacementMapElement::ComputeChangeBBox(const nsTArray<nsIntRect>& aSourceChangeBoxes,
const nsSVGFilterInstance& aInstance)
{
// XXX we could do something clever here involving analysis of 'scale'
// to figure out the maximum displacement
return GetMaxRect();
}
nsIntRect
SVGFEImageElement::ComputeTargetBBox(const nsTArray<nsIntRect>& aSourceBBoxes,
const nsSVGFilterInstance& aInstance)
{
// XXX can do better here ... we could check what we know of the source
// image bounds and compute an accurate bounding box for the filter
// primitive result.
return GetMaxRect();
}
nsIntRect
SVGFEDisplacementMapElement::ComputeTargetBBox(const nsTArray<nsIntRect>& aSourceBBoxes,
const nsSVGFilterInstance& aInstance)
{
// XXX we could do something clever here involving analysis of 'scale'
// to figure out the maximum displacement, and then return mIn1's bounds
// adjusted for the maximum displacement
return GetMaxRect();
}
nsIntRect
SVGFETurbulenceElement::ComputeTargetBBox(const nsTArray<nsIntRect>& aSourceBBoxes,
const nsSVGFilterInstance& aInstance)
{
return GetMaxRect();
}
