blob: 3a885c210765c703ce0c8619782821f7d591e2c9 [file] [log] [blame]
/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "modules/svg/include/SkSVGPattern.h"
#include "include/core/SkPictureRecorder.h"
#include "include/core/SkShader.h"
#include "modules/svg/include/SkSVGRenderContext.h"
#include "modules/svg/include/SkSVGValue.h"
SkSVGPattern::SkSVGPattern() : INHERITED(SkSVGTag::kPattern) {}
bool SkSVGPattern::parseAndSetAttribute(const char* name, const char* value) {
return INHERITED::parseAndSetAttribute(name, value) ||
this->setX(SkSVGAttributeParser::parse<SkSVGLength>("x", name, value)) ||
this->setY(SkSVGAttributeParser::parse<SkSVGLength>("y", name, value)) ||
this->setWidth(SkSVGAttributeParser::parse<SkSVGLength>("width", name, value)) ||
this->setHeight(SkSVGAttributeParser::parse<SkSVGLength>("height", name, value)) ||
this->setPatternTransform(SkSVGAttributeParser::parse<SkSVGTransformType>(
"patternTransform", name, value)) ||
this->setHref(SkSVGAttributeParser::parse<SkSVGIRI>("xlink:href", name, value));
}
const SkSVGPattern* SkSVGPattern::hrefTarget(const SkSVGRenderContext& ctx) const {
if (fHref.iri().isEmpty()) {
return nullptr;
}
const auto href = ctx.findNodeById(fHref);
if (!href || href->tag() != SkSVGTag::kPattern) {
return nullptr;
}
return static_cast<const SkSVGPattern*>(href.get());
}
template <typename T>
int inherit_if_needed(const SkTLazy<T>& src, SkTLazy<T>& dst) {
if (!dst.isValid()) {
dst = src;
return 1;
}
return 0;
}
/* https://www.w3.org/TR/SVG11/pservers.html#PatternElementHrefAttribute
*
* Any attributes which are defined on the referenced element which are not defined on this element
* are inherited by this element. If this element has no children, and the referenced element does
* (possibly due to its own ‘xlink:href’ attribute), then this element inherits the children from
* the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the
* referenced element inherits attributes or children due to its own ‘xlink:href’ attribute, then
* the current element can inherit those attributes or children.
*/
const SkSVGPattern* SkSVGPattern::resolveHref(const SkSVGRenderContext& ctx,
PatternAttributes* attrs) const {
const SkSVGPattern *currentNode = this,
*contentNode = this;
do {
// Bitwise OR to avoid short-circuiting.
const bool didInherit =
inherit_if_needed(currentNode->fX , attrs->fX) |
inherit_if_needed(currentNode->fY , attrs->fY) |
inherit_if_needed(currentNode->fWidth , attrs->fWidth) |
inherit_if_needed(currentNode->fHeight , attrs->fHeight) |
inherit_if_needed(currentNode->fPatternTransform, attrs->fPatternTransform);
if (!contentNode->hasChildren()) {
contentNode = currentNode;
}
if (contentNode->hasChildren() && !didInherit) {
// All attributes have been resolved, and a valid content node has been found.
// We can terminate the href chain early.
break;
}
// TODO: reference loop mitigation.
currentNode = currentNode->hrefTarget(ctx);
} while (currentNode);
return contentNode;
}
bool SkSVGPattern::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
PatternAttributes attrs;
const auto* contentNode = this->resolveHref(ctx, &attrs);
const auto tile = ctx.lengthContext().resolveRect(
attrs.fX.isValid() ? *attrs.fX : SkSVGLength(0),
attrs.fY.isValid() ? *attrs.fY : SkSVGLength(0),
attrs.fWidth.isValid() ? *attrs.fWidth : SkSVGLength(0),
attrs.fHeight.isValid() ? *attrs.fHeight : SkSVGLength(0));
if (tile.isEmpty()) {
return false;
}
const SkMatrix* patternTransform = attrs.fPatternTransform.isValid()
? attrs.fPatternTransform.get()
: nullptr;
SkPictureRecorder recorder;
SkSVGRenderContext recordingContext(ctx, recorder.beginRecording(tile));
// Cannot call into INHERITED:: because SkSVGHiddenContainer skips rendering.
contentNode->SkSVGContainer::onRender(recordingContext);
paint->setShader(recorder.finishRecordingAsPicture()->makeShader(
SkTileMode::kRepeat,
SkTileMode::kRepeat,
SkFilterMode::kLinear,
patternTransform,
&tile));
return true;
}