Florin Malita | 1aa1bb6 | 2017-10-11 14:34:33 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2017 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "SkSVGPattern.h" |
| 9 | |
| 10 | #include "SkPictureRecorder.h" |
| 11 | #include "SkShader.h" |
| 12 | #include "SkSVGRenderContext.h" |
| 13 | #include "SkSVGValue.h" |
| 14 | |
| 15 | SkSVGPattern::SkSVGPattern() : INHERITED(SkSVGTag::kPattern) {} |
| 16 | |
| 17 | void SkSVGPattern::setX(const SkSVGLength& x) { |
| 18 | fAttributes.fX.set(x); |
| 19 | } |
| 20 | |
| 21 | void SkSVGPattern::setY(const SkSVGLength& y) { |
| 22 | fAttributes.fY.set(y); |
| 23 | } |
| 24 | |
| 25 | void SkSVGPattern::setWidth(const SkSVGLength& w) { |
| 26 | fAttributes.fWidth.set(w); |
| 27 | } |
| 28 | |
| 29 | void SkSVGPattern::setHeight(const SkSVGLength& h) { |
| 30 | fAttributes.fHeight.set(h); |
| 31 | } |
| 32 | |
| 33 | void SkSVGPattern::setHref(const SkSVGStringType& href) { |
| 34 | fHref = std::move(href); |
| 35 | } |
| 36 | |
| 37 | void SkSVGPattern::setPatternTransform(const SkSVGTransformType& patternTransform) { |
| 38 | fAttributes.fPatternTransform.set(patternTransform); |
| 39 | } |
| 40 | |
| 41 | void SkSVGPattern::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) { |
| 42 | switch (attr) { |
| 43 | case SkSVGAttribute::kX: |
| 44 | if (const auto* x = v.as<SkSVGLengthValue>()) { |
| 45 | this->setX(*x); |
| 46 | } |
| 47 | break; |
| 48 | case SkSVGAttribute::kY: |
| 49 | if (const auto* y = v.as<SkSVGLengthValue>()) { |
| 50 | this->setY(*y); |
| 51 | } |
| 52 | break; |
| 53 | case SkSVGAttribute::kWidth: |
| 54 | if (const auto* w = v.as<SkSVGLengthValue>()) { |
| 55 | this->setWidth(*w); |
| 56 | } |
| 57 | break; |
| 58 | case SkSVGAttribute::kHeight: |
| 59 | if (const auto* h = v.as<SkSVGLengthValue>()) { |
| 60 | this->setHeight(*h); |
| 61 | } |
| 62 | break; |
| 63 | case SkSVGAttribute::kHref: |
| 64 | if (const auto* href = v.as<SkSVGStringValue>()) { |
| 65 | this->setHref(*href); |
| 66 | } |
| 67 | break; |
| 68 | case SkSVGAttribute::kPatternTransform: |
| 69 | if (const auto* t = v.as<SkSVGTransformValue>()) { |
| 70 | this->setPatternTransform(*t); |
| 71 | } |
| 72 | break; |
| 73 | default: |
| 74 | this->INHERITED::onSetAttribute(attr, v); |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | const SkSVGPattern* SkSVGPattern::hrefTarget(const SkSVGRenderContext& ctx) const { |
| 79 | if (fHref.value().isEmpty()) { |
| 80 | return nullptr; |
| 81 | } |
| 82 | |
| 83 | const auto* href = ctx.findNodeById(fHref); |
| 84 | if (!href || href->tag() != SkSVGTag::kPattern) { |
| 85 | return nullptr; |
| 86 | } |
| 87 | |
| 88 | return static_cast<const SkSVGPattern*>(href); |
| 89 | } |
| 90 | |
| 91 | template <typename T> |
| 92 | bool inherit_if_needed(const SkTLazy<T>& src, SkTLazy<T>& dst) { |
| 93 | if (!dst.isValid()) { |
| 94 | dst = src; |
| 95 | return true; |
| 96 | } |
| 97 | |
| 98 | return false; |
| 99 | } |
| 100 | |
| 101 | /* https://www.w3.org/TR/SVG/pservers.html#PatternElementHrefAttribute |
| 102 | * |
| 103 | * Any attributes which are defined on the referenced element which are not defined on this element |
| 104 | * are inherited by this element. If this element has no children, and the referenced element does |
| 105 | * (possibly due to its own ‘xlink:href’ attribute), then this element inherits the children from |
| 106 | * the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the |
| 107 | * referenced element inherits attributes or children due to its own ‘xlink:href’ attribute, then |
| 108 | * the current element can inherit those attributes or children. |
| 109 | */ |
| 110 | const SkSVGPattern* SkSVGPattern::resolveHref(const SkSVGRenderContext& ctx, |
| 111 | PatternAttributes* attrs) const { |
| 112 | const SkSVGPattern *currentNode = this, |
| 113 | *contentNode = this; |
| 114 | do { |
| 115 | // Bitwise OR to avoid short-circuiting. |
| 116 | const bool didInherit = |
| 117 | inherit_if_needed(currentNode->fAttributes.fX , attrs->fX) | |
| 118 | inherit_if_needed(currentNode->fAttributes.fY , attrs->fY) | |
| 119 | inherit_if_needed(currentNode->fAttributes.fWidth , attrs->fWidth) | |
| 120 | inherit_if_needed(currentNode->fAttributes.fHeight , attrs->fHeight) | |
| 121 | inherit_if_needed(currentNode->fAttributes.fPatternTransform, attrs->fPatternTransform); |
| 122 | |
| 123 | if (!contentNode->hasChildren()) { |
| 124 | contentNode = currentNode; |
| 125 | } |
| 126 | |
| 127 | if (contentNode->hasChildren() && !didInherit) { |
| 128 | // All attributes have been resolved, and a valid content node has been found. |
| 129 | // We can terminate the href chain early. |
| 130 | break; |
| 131 | } |
| 132 | |
| 133 | // TODO: reference loop mitigation. |
| 134 | currentNode = currentNode->hrefTarget(ctx); |
| 135 | } while (currentNode); |
| 136 | |
| 137 | return contentNode; |
| 138 | } |
| 139 | |
| 140 | bool SkSVGPattern::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const { |
| 141 | PatternAttributes attrs; |
| 142 | const auto* contentNode = this->resolveHref(ctx, &attrs); |
| 143 | |
| 144 | const auto tile = ctx.lengthContext().resolveRect( |
| 145 | attrs.fX.isValid() ? *attrs.fX.get() : SkSVGLength(0), |
| 146 | attrs.fY.isValid() ? *attrs.fY.get() : SkSVGLength(0), |
| 147 | attrs.fWidth.isValid() ? *attrs.fWidth.get() : SkSVGLength(0), |
| 148 | attrs.fHeight.isValid() ? *attrs.fHeight.get() : SkSVGLength(0)); |
| 149 | |
| 150 | if (tile.isEmpty()) { |
| 151 | return false; |
| 152 | } |
| 153 | |
| 154 | const SkMatrix* patternTransform = attrs.fPatternTransform.isValid() |
| 155 | ? &attrs.fPatternTransform.get()->value() |
| 156 | : nullptr; |
| 157 | |
| 158 | SkPictureRecorder recorder; |
| 159 | SkSVGRenderContext recordingContext(ctx, recorder.beginRecording(tile)); |
| 160 | |
| 161 | // Cannot call into INHERITED:: because SkSVGHiddenContainer skips rendering. |
| 162 | contentNode->SkSVGContainer::onRender(recordingContext); |
| 163 | |
| 164 | paint->setShader(SkShader::MakePictureShader(recorder.finishRecordingAsPicture(), |
| 165 | SkShader::kRepeat_TileMode, |
| 166 | SkShader::kRepeat_TileMode, |
| 167 | patternTransform, |
| 168 | &tile)); |
| 169 | return true; |
| 170 | } |