27aeb12d47
Several SVG constructs reference other elements based on their ID (e.g.
<use>). This can yield arbitrary reference chains and cycles.
Since all ID-based lookups are funneled through
SkSVGRenderContext::findNodeById(), a straightforward method to break
cycles is to temporarily clear the id->node association following a
lookup -- where "temporarily" refers to the local execution scope.
This approach works for all recursive traversals, as scopes are
nested/released in a natural manner.
- introduce a scoped node reference wrapper (BorrowedNode), which
clears the id mapping for its lifetime and restores it upon
destruction
- update findNodeById() return BorrowedNode values
- update call sites as needed
Change-Id: I2ec5539b24e23b4fbbaff01a44460c41190028e0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/282271
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Tyler Denniston <tdenniston@google.com>
101 lines
3.6 KiB
C++
101 lines
3.6 KiB
C++
/*
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* Copyright 2017 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "experimental/svg/model/SkSVGGradient.h"
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#include "experimental/svg/model/SkSVGRenderContext.h"
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#include "experimental/svg/model/SkSVGStop.h"
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#include "experimental/svg/model/SkSVGValue.h"
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void SkSVGGradient::setHref(const SkSVGStringType& href) {
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fHref = std::move(href);
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}
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void SkSVGGradient::setGradientTransform(const SkSVGTransformType& t) {
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fGradientTransform = t;
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}
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void SkSVGGradient::setSpreadMethod(const SkSVGSpreadMethod& spread) {
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fSpreadMethod = spread;
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}
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void SkSVGGradient::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
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switch (attr) {
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case SkSVGAttribute::kGradientTransform:
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if (const auto* t = v.as<SkSVGTransformValue>()) {
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this->setGradientTransform(*t);
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}
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break;
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case SkSVGAttribute::kHref:
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if (const auto* href = v.as<SkSVGStringValue>()) {
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this->setHref(*href);
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}
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break;
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case SkSVGAttribute::kSpreadMethod:
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if (const auto* spread = v.as<SkSVGSpreadMethodValue>()) {
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this->setSpreadMethod(*spread);
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}
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break;
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default:
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this->INHERITED::onSetAttribute(attr, v);
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}
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}
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// https://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementHrefAttribute
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void SkSVGGradient::collectColorStops(const SkSVGRenderContext& ctx,
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StopPositionArray* pos,
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StopColorArray* colors) const {
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// Used to resolve percentage offsets.
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const SkSVGLengthContext ltx(SkSize::Make(1, 1));
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for (const auto& child : fChildren) {
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if (child->tag() != SkSVGTag::kStop) {
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continue;
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}
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const auto& stop = static_cast<const SkSVGStop&>(*child);
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colors->push_back(SkColorSetA(stop.stopColor(),
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SkScalarRoundToInt(stop.stopOpacity() * 255)));
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pos->push_back(SkTPin(ltx.resolve(stop.offset(), SkSVGLengthContext::LengthType::kOther),
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0.f, 1.f));
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}
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SkASSERT(colors->count() == pos->count());
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if (pos->empty() && !fHref.value().isEmpty()) {
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const auto ref = ctx.findNodeById(fHref);
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if (ref && (ref->tag() == SkSVGTag::kLinearGradient ||
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ref->tag() == SkSVGTag::kRadialGradient)) {
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static_cast<const SkSVGGradient*>(ref.get())->collectColorStops(ctx, pos, colors);
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}
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}
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}
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bool SkSVGGradient::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
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StopColorArray colors;
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StopPositionArray pos;
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this->collectColorStops(ctx, &pos, &colors);
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// TODO:
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// * stop (lazy?) sorting
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// * href loop detection
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// * href attribute inheritance (not just color stops)
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// * objectBoundingBox units support
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static_assert(static_cast<SkTileMode>(SkSVGSpreadMethod::Type::kPad) ==
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SkTileMode::kClamp, "SkSVGSpreadMethod::Type is out of sync");
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static_assert(static_cast<SkTileMode>(SkSVGSpreadMethod::Type::kRepeat) ==
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SkTileMode::kRepeat, "SkSVGSpreadMethod::Type is out of sync");
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static_assert(static_cast<SkTileMode>(SkSVGSpreadMethod::Type::kReflect) ==
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SkTileMode::kMirror, "SkSVGSpreadMethod::Type is out of sync");
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const auto tileMode = static_cast<SkTileMode>(fSpreadMethod.type());
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paint->setShader(this->onMakeShader(ctx, colors.begin(), pos.begin(), colors.count(), tileMode,
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fGradientTransform.value()));
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return true;
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}
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