1 /*
2 * Copyright 2020 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 "modules/svg/include/SkSVGFe.h"
9
10 #include "modules/svg/include/SkSVGAttribute.h"
11 #include "modules/svg/include/SkSVGAttributeParser.h"
12 #include "modules/svg/include/SkSVGFilterContext.h"
13 #include "modules/svg/include/SkSVGRenderContext.h"
14
15 #include <cstddef>
16 #include <tuple>
17
makeImageFilter(const SkSVGRenderContext & ctx,const SkSVGFilterContext & fctx) const18 sk_sp<SkImageFilter> SkSVGFe::makeImageFilter(const SkSVGRenderContext& ctx,
19 const SkSVGFilterContext& fctx) const {
20 return this->onMakeImageFilter(ctx, fctx);
21 }
22
resolveBoundaries(const SkSVGRenderContext & ctx,const SkSVGFilterContext & fctx) const23 SkRect SkSVGFe::resolveBoundaries(const SkSVGRenderContext& ctx,
24 const SkSVGFilterContext& fctx) const {
25 const auto x = fX.isValid() ? *fX : SkSVGLength(0, SkSVGLength::Unit::kPercentage);
26 const auto y = fY.isValid() ? *fY : SkSVGLength(0, SkSVGLength::Unit::kPercentage);
27 const auto w = fWidth.isValid() ? *fWidth : SkSVGLength(100, SkSVGLength::Unit::kPercentage);
28 const auto h = fHeight.isValid() ? *fHeight : SkSVGLength(100, SkSVGLength::Unit::kPercentage);
29
30 return ctx.resolveOBBRect(x, y, w, h, fctx.primitiveUnits());
31 }
32
AnyIsStandardInput(const SkSVGFilterContext & fctx,const std::vector<SkSVGFeInputType> & inputs)33 static bool AnyIsStandardInput(const SkSVGFilterContext& fctx,
34 const std::vector<SkSVGFeInputType>& inputs) {
35 for (const auto& in : inputs) {
36 switch (in.type()) {
37 case SkSVGFeInputType::Type::kFilterPrimitiveReference:
38 break;
39 case SkSVGFeInputType::Type::kSourceGraphic:
40 case SkSVGFeInputType::Type::kSourceAlpha:
41 case SkSVGFeInputType::Type::kBackgroundImage:
42 case SkSVGFeInputType::Type::kBackgroundAlpha:
43 case SkSVGFeInputType::Type::kFillPaint:
44 case SkSVGFeInputType::Type::kStrokePaint:
45 return true;
46 case SkSVGFeInputType::Type::kUnspecified:
47 // Unspecified means previous result (which may be SourceGraphic).
48 if (fctx.previousResultIsSourceGraphic()) {
49 return true;
50 }
51 break;
52 }
53 }
54
55 return false;
56 }
57
resolveFilterSubregion(const SkSVGRenderContext & ctx,const SkSVGFilterContext & fctx) const58 SkRect SkSVGFe::resolveFilterSubregion(const SkSVGRenderContext& ctx,
59 const SkSVGFilterContext& fctx) const {
60 // From https://www.w3.org/TR/SVG11/filters.html#FilterPrimitiveSubRegion,
61 // the default filter effect subregion is equal to the union of the subregions defined
62 // for all "referenced nodes" (filter effect inputs). If there are no inputs, the
63 // default subregion is equal to the filter effects region
64 // (https://www.w3.org/TR/SVG11/filters.html#FilterEffectsRegion).
65 const std::vector<SkSVGFeInputType> inputs = this->getInputs();
66 SkRect defaultSubregion;
67 if (inputs.empty() || AnyIsStandardInput(fctx, inputs)) {
68 defaultSubregion = fctx.filterEffectsRegion();
69 } else {
70 defaultSubregion = fctx.filterPrimitiveSubregion(inputs[0]);
71 for (size_t i = 1; i < inputs.size(); i++) {
72 defaultSubregion.join(fctx.filterPrimitiveSubregion(inputs[i]));
73 }
74 }
75
76 // Next resolve the rect specified by the x, y, width, height attributes on this filter effect.
77 // If those attributes were given, they override the corresponding attribute of the default
78 // filter effect subregion calculated above.
79 const SkRect boundaries = this->resolveBoundaries(ctx, fctx);
80
81 // Compute and return the fully resolved subregion.
82 return SkRect::MakeXYWH(fX.isValid() ? boundaries.fLeft : defaultSubregion.fLeft,
83 fY.isValid() ? boundaries.fTop : defaultSubregion.fTop,
84 fWidth.isValid() ? boundaries.width() : defaultSubregion.width(),
85 fHeight.isValid() ? boundaries.height() : defaultSubregion.height());
86 }
87
resolveColorspace(const SkSVGRenderContext & ctx,const SkSVGFilterContext &) const88 SkSVGColorspace SkSVGFe::resolveColorspace(const SkSVGRenderContext& ctx,
89 const SkSVGFilterContext&) const {
90 constexpr SkSVGColorspace kDefaultCS = SkSVGColorspace::kSRGB;
91 const SkSVGColorspace cs = *ctx.presentationContext().fInherited.fColorInterpolationFilters;
92 return cs == SkSVGColorspace::kAuto ? kDefaultCS : cs;
93 }
94
applyProperties(SkSVGRenderContext * ctx) const95 void SkSVGFe::applyProperties(SkSVGRenderContext* ctx) const { this->onPrepareToRender(ctx); }
96
parseAndSetAttribute(const char * name,const char * value)97 bool SkSVGFe::parseAndSetAttribute(const char* name, const char* value) {
98 return INHERITED::parseAndSetAttribute(name, value) ||
99 this->setIn(SkSVGAttributeParser::parse<SkSVGFeInputType>("in", name, value)) ||
100 this->setResult(SkSVGAttributeParser::parse<SkSVGStringType>("result", name, value)) ||
101 this->setX(SkSVGAttributeParser::parse<SkSVGLength>("x", name, value)) ||
102 this->setY(SkSVGAttributeParser::parse<SkSVGLength>("y", name, value)) ||
103 this->setWidth(SkSVGAttributeParser::parse<SkSVGLength>("width", name, value)) ||
104 this->setHeight(SkSVGAttributeParser::parse<SkSVGLength>("height", name, value));
105 }
106
parse(SkSVGFeInputType * type)107 template <> bool SkSVGAttributeParser::parse(SkSVGFeInputType* type) {
108 static constexpr std::tuple<const char*, SkSVGFeInputType::Type> gTypeMap[] = {
109 {"SourceGraphic", SkSVGFeInputType::Type::kSourceGraphic},
110 {"SourceAlpha", SkSVGFeInputType::Type::kSourceAlpha},
111 {"BackgroundImage", SkSVGFeInputType::Type::kBackgroundImage},
112 {"BackgroundAlpha", SkSVGFeInputType::Type::kBackgroundAlpha},
113 {"FillPaint", SkSVGFeInputType::Type::kFillPaint},
114 {"StrokePaint", SkSVGFeInputType::Type::kStrokePaint},
115 };
116
117 SkSVGStringType resultId;
118 SkSVGFeInputType::Type t;
119 bool parsedValue = false;
120 if (this->parseEnumMap(gTypeMap, &t)) {
121 *type = SkSVGFeInputType(t);
122 parsedValue = true;
123 } else if (parse(&resultId)) {
124 *type = SkSVGFeInputType(resultId);
125 parsedValue = true;
126 }
127
128 return parsedValue && this->parseEOSToken();
129 }
130