bool LayoutSVGResourceClipper::calculateClipContentPathIfNeeded()
{
if (!m_clipContentPath.isEmpty())
return true;
// If the current clip-path gets clipped itself, we have to fallback to masking.
if (style()->svgStyle().hasClipper())
return false;
unsigned opCount = 0;
bool usingBuilder = false;
SkOpBuilder clipPathBuilder;
for (SVGElement* childElement = Traversal<SVGElement>::firstChild(*element()); childElement; childElement = Traversal<SVGElement>::nextSibling(*childElement)) {
LayoutObject* childLayoutObject = childElement->layoutObject();
if (!childLayoutObject)
continue;
// Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.
if (childLayoutObject->isSVGText()) {
m_clipContentPath.clear();
return false;
}
if (!childElement->isSVGGraphicsElement())
continue;
const ComputedStyle* style = childLayoutObject->style();
if (!style || style->display() == NONE || style->visibility() != VISIBLE)
continue;
// Current shape in clip-path gets clipped too. Fallback to masking.
if (style->svgStyle().hasClipper()) {
m_clipContentPath.clear();
return false;
}
// First clip shape.
if (m_clipContentPath.isEmpty()) {
if (isSVGGeometryElement(childElement))
toSVGGeometryElement(childElement)->toClipPath(m_clipContentPath);
else if (isSVGUseElement(childElement))
toSVGUseElement(childElement)->toClipPath(m_clipContentPath);
continue;
}
// Multiple shapes require PathOps. In some degenerate cases PathOps can exhibit quadratic
// behavior, so we cap the number of ops to a reasonable count.
const unsigned kMaxOps = 42;
if (!RuntimeEnabledFeatures::pathOpsSVGClippingEnabled() || ++opCount > kMaxOps) {
m_clipContentPath.clear();
return false;
}
// Second clip shape => start using the builder.
if (!usingBuilder) {
clipPathBuilder.add(m_clipContentPath.skPath(), kUnion_SkPathOp);
usingBuilder = true;
}
Path subPath;
if (isSVGGeometryElement(childElement))
toSVGGeometryElement(childElement)->toClipPath(subPath);
else if (isSVGUseElement(childElement))
toSVGUseElement(childElement)->toClipPath(subPath);
clipPathBuilder.add(subPath.skPath(), kUnion_SkPathOp);
}
if (usingBuilder) {
SkPath resolvedPath;
clipPathBuilder.resolve(&resolvedPath);
m_clipContentPath = resolvedPath;
}
return true;
}
bool RenderSVGResourceClipper::tryPathOnlyClipping(GraphicsContext* context,
const AffineTransform& animatedLocalTransform, const FloatRect& objectBoundingBox) {
// If the current clip-path gets clipped itself, we have to fallback to masking.
if (!style()->svgStyle().clipperResource().isEmpty())
return false;
WindRule clipRule = RULE_NONZERO;
Path clipPath = Path();
for (SVGElement* childElement = Traversal<SVGElement>::firstChild(*element()); childElement; childElement = Traversal<SVGElement>::nextSibling(*childElement)) {
RenderObject* renderer = childElement->renderer();
if (!renderer)
continue;
// Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.
if (renderer->isSVGText())
return false;
if (!childElement->isSVGGraphicsElement())
continue;
SVGGraphicsElement* styled = toSVGGraphicsElement(childElement);
RenderStyle* style = renderer->style();
if (!style || style->display() == NONE || style->visibility() != VISIBLE)
continue;
const SVGRenderStyle& svgStyle = style->svgStyle();
// Current shape in clip-path gets clipped too. Fallback to masking.
if (!svgStyle.clipperResource().isEmpty())
return false;
if (clipPath.isEmpty()) {
// First clip shape.
styled->toClipPath(clipPath);
clipRule = svgStyle.clipRule();
clipPath.setWindRule(clipRule);
continue;
}
if (RuntimeEnabledFeatures::pathOpsSVGClippingEnabled()) {
// Attempt to generate a combined clip path, fall back to masking if not possible.
Path subPath;
styled->toClipPath(subPath);
subPath.setWindRule(svgStyle.clipRule());
if (!clipPath.unionPath(subPath))
return false;
} else {
return false;
}
}
// Only one visible shape/path was found. Directly continue clipping and transform the content to userspace if necessary.
if (clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
AffineTransform transform;
transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
clipPath.transform(transform);
}
// Transform path by animatedLocalTransform.
clipPath.transform(animatedLocalTransform);
// The SVG specification wants us to clip everything, if clip-path doesn't have a child.
if (clipPath.isEmpty())
clipPath.addRect(FloatRect());
context->clipPath(clipPath, clipRule);
return true;
}