122 lines
4.8 KiB
C++
122 lines
4.8 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 "modules/svg/include/SkSVGPattern.h"
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#include "include/core/SkPictureRecorder.h"
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#include "include/core/SkShader.h"
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#include "modules/svg/include/SkSVGRenderContext.h"
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#include "modules/svg/include/SkSVGValue.h"
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SkSVGPattern::SkSVGPattern() : INHERITED(SkSVGTag::kPattern) {}
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bool SkSVGPattern::parseAndSetAttribute(const char* name, const char* value) {
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return INHERITED::parseAndSetAttribute(name, value) ||
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this->setX(SkSVGAttributeParser::parse<SkSVGLength>("x", name, value)) ||
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this->setY(SkSVGAttributeParser::parse<SkSVGLength>("y", name, value)) ||
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this->setWidth(SkSVGAttributeParser::parse<SkSVGLength>("width", name, value)) ||
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this->setHeight(SkSVGAttributeParser::parse<SkSVGLength>("height", name, value)) ||
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this->setPatternTransform(SkSVGAttributeParser::parse<SkSVGTransformType>(
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"patternTransform", name, value)) ||
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this->setHref(SkSVGAttributeParser::parse<SkSVGIRI>("xlink:href", name, value));
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}
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const SkSVGPattern* SkSVGPattern::hrefTarget(const SkSVGRenderContext& ctx) const {
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if (fHref.iri().isEmpty()) {
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return nullptr;
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}
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const auto href = ctx.findNodeById(fHref);
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if (!href || href->tag() != SkSVGTag::kPattern) {
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return nullptr;
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}
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return static_cast<const SkSVGPattern*>(href.get());
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}
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template <typename T>
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int inherit_if_needed(const SkTLazy<T>& src, SkTLazy<T>& dst) {
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if (!dst.isValid()) {
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dst = src;
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return 1;
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}
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return 0;
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}
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/* https://www.w3.org/TR/SVG11/pservers.html#PatternElementHrefAttribute
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*
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* Any attributes which are defined on the referenced element which are not defined on this element
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* are inherited by this element. If this element has no children, and the referenced element does
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* (possibly due to its own ‘xlink:href’ attribute), then this element inherits the children from
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* the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the
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* referenced element inherits attributes or children due to its own ‘xlink:href’ attribute, then
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* the current element can inherit those attributes or children.
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*/
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const SkSVGPattern* SkSVGPattern::resolveHref(const SkSVGRenderContext& ctx,
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PatternAttributes* attrs) const {
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const SkSVGPattern *currentNode = this,
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*contentNode = this;
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do {
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// Bitwise OR to avoid short-circuiting.
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const bool didInherit =
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inherit_if_needed(currentNode->fX , attrs->fX) |
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inherit_if_needed(currentNode->fY , attrs->fY) |
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inherit_if_needed(currentNode->fWidth , attrs->fWidth) |
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inherit_if_needed(currentNode->fHeight , attrs->fHeight) |
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inherit_if_needed(currentNode->fPatternTransform, attrs->fPatternTransform);
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if (!contentNode->hasChildren()) {
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contentNode = currentNode;
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}
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if (contentNode->hasChildren() && !didInherit) {
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// All attributes have been resolved, and a valid content node has been found.
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// We can terminate the href chain early.
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break;
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}
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// TODO: reference loop mitigation.
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currentNode = currentNode->hrefTarget(ctx);
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} while (currentNode);
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return contentNode;
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}
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bool SkSVGPattern::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
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PatternAttributes attrs;
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const auto* contentNode = this->resolveHref(ctx, &attrs);
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const auto tile = ctx.lengthContext().resolveRect(
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attrs.fX.isValid() ? *attrs.fX : SkSVGLength(0),
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attrs.fY.isValid() ? *attrs.fY : SkSVGLength(0),
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attrs.fWidth.isValid() ? *attrs.fWidth : SkSVGLength(0),
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attrs.fHeight.isValid() ? *attrs.fHeight : SkSVGLength(0));
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if (tile.isEmpty()) {
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return false;
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}
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const SkMatrix* patternTransform = attrs.fPatternTransform.isValid()
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? attrs.fPatternTransform.get()
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: nullptr;
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SkPictureRecorder recorder;
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SkSVGRenderContext recordingContext(ctx, recorder.beginRecording(tile));
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// Cannot call into INHERITED:: because SkSVGHiddenContainer skips rendering.
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contentNode->SkSVGContainer::onRender(recordingContext);
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paint->setShader(recorder.finishRecordingAsPicture()->makeShader(
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SkTileMode::kRepeat,
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SkTileMode::kRepeat,
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SkFilterMode::kLinear,
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patternTransform,
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&tile));
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return true;
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}
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