1 /*
2 * Copyright 2021 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/SkSVGImage.h"
9
10 #include "include/core/SkCanvas.h"
11 #include "include/core/SkImage.h"
12 #include "include/core/SkMatrix.h"
13 #include "include/core/SkSamplingOptions.h"
14 #include "include/core/SkString.h"
15 #include "include/private/base/SkAssert.h"
16 #include "modules/skresources/include/SkResources.h"
17 #include "modules/svg/include/SkSVGAttributeParser.h"
18 #include "modules/svg/include/SkSVGRenderContext.h"
19 #include "src/utils/SkOSPath.h"
20
21 #include <utility>
22
parseAndSetAttribute(const char * n,const char * v)23 bool SkSVGImage::parseAndSetAttribute(const char* n, const char* v) {
24 return INHERITED::parseAndSetAttribute(n, v) ||
25 this->setX(SkSVGAttributeParser::parse<SkSVGLength>("x", n, v)) ||
26 this->setY(SkSVGAttributeParser::parse<SkSVGLength>("y", n, v)) ||
27 this->setWidth(SkSVGAttributeParser::parse<SkSVGLength>("width", n, v)) ||
28 this->setHeight(SkSVGAttributeParser::parse<SkSVGLength>("height", n, v)) ||
29 this->setHref(SkSVGAttributeParser::parse<SkSVGIRI>("xlink:href", n, v)) ||
30 this->setPreserveAspectRatio(SkSVGAttributeParser::parse<SkSVGPreserveAspectRatio>(
31 "preserveAspectRatio", n, v));
32 }
33
onPrepareToRender(SkSVGRenderContext * ctx) const34 bool SkSVGImage::onPrepareToRender(SkSVGRenderContext* ctx) const {
35 // Width or height of 0 disables rendering per spec:
36 // https://www.w3.org/TR/SVG11/struct.html#ImageElement
37 return !fHref.iri().isEmpty() && fWidth.value() > 0 && fHeight.value() > 0 &&
38 INHERITED::onPrepareToRender(ctx);
39 }
40
LoadImage(const sk_sp<skresources::ResourceProvider> & rp,const SkSVGIRI & href)41 static sk_sp<SkImage> LoadImage(const sk_sp<skresources::ResourceProvider>& rp,
42 const SkSVGIRI& href) {
43 // TODO: It may be better to use the SVG 'id' attribute as the asset id, to allow
44 // clients to perform asset substitution based on element id.
45 sk_sp<skresources::ImageAsset> imageAsset;
46 switch (href.type()) {
47 case SkSVGIRI::Type::kDataURI:
48 imageAsset = rp->loadImageAsset("", href.iri().c_str(), "");
49 break;
50 case SkSVGIRI::Type::kNonlocal: {
51 const auto path = SkOSPath::Dirname(href.iri().c_str());
52 const auto name = SkOSPath::Basename(href.iri().c_str());
53 imageAsset = rp->loadImageAsset(path.c_str(), name.c_str(), /* id */ name.c_str());
54 break;
55 }
56 default:
57 SkDEBUGF("error loading image: unhandled iri type %d\n", (int)href.type());
58 return nullptr;
59 }
60
61 return imageAsset ? imageAsset->getFrameData(0).image : nullptr;
62 }
63
LoadImage(const sk_sp<skresources::ResourceProvider> & rp,const SkSVGIRI & iri,const SkRect & viewPort,SkSVGPreserveAspectRatio par)64 SkSVGImage::ImageInfo SkSVGImage::LoadImage(const sk_sp<skresources::ResourceProvider>& rp,
65 const SkSVGIRI& iri,
66 const SkRect& viewPort,
67 SkSVGPreserveAspectRatio par) {
68 SkASSERT(rp);
69
70 // TODO: svg sources
71 sk_sp<SkImage> image = ::LoadImage(rp, iri);
72 if (!image) {
73 return {};
74 }
75
76 // Per spec: raster content has implicit viewbox of '0 0 width height'.
77 const SkRect viewBox = SkRect::Make(image->bounds());
78
79 // Map and place at x, y specified by viewport
80 const SkMatrix m = ComputeViewboxMatrix(viewBox, viewPort, par);
81 const SkRect dst = m.mapRect(viewBox).makeOffset(viewPort.fLeft, viewPort.fTop);
82
83 return {std::move(image), dst};
84 }
85
onRender(const SkSVGRenderContext & ctx) const86 void SkSVGImage::onRender(const SkSVGRenderContext& ctx) const {
87 // Per spec: x, w, width, height attributes establish the new viewport.
88 const SkSVGLengthContext& lctx = ctx.lengthContext();
89 const SkRect viewPort = lctx.resolveRect(fX, fY, fWidth, fHeight);
90
91 const auto imgInfo = LoadImage(ctx.resourceProvider(), fHref, viewPort, fPreserveAspectRatio);
92 if (!imgInfo.fImage) {
93 SkDEBUGF("can't render image: load image failed\n");
94 return;
95 }
96
97 // TODO: image-rendering property
98 ctx.canvas()->drawImageRect(
99 imgInfo.fImage, imgInfo.fDst, SkSamplingOptions(SkFilterMode::kLinear));
100 }
101
onAsPath(const SkSVGRenderContext &) const102 SkPath SkSVGImage::onAsPath(const SkSVGRenderContext&) const { return {}; }
103
onObjectBoundingBox(const SkSVGRenderContext & ctx) const104 SkRect SkSVGImage::onObjectBoundingBox(const SkSVGRenderContext& ctx) const {
105 const SkSVGLengthContext& lctx = ctx.lengthContext();
106 return lctx.resolveRect(fX, fY, fWidth, fHeight);
107 }
108