[SVGDom] Expose intrinsic size info

  * expose intrinsic size info on <svg> nodes.

  * tweak the SkSVGDOM constructor to no longer take an container size
    param, but instead default to intrinsic size
  * update clients to call SkSVGDOM::setContainerSize() explicitly, when
    needed

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2345533002

Review-Url: https://codereview.chromium.org/2345533002

4 files changed, 46 insertions, 9 deletions

diff --git a/experimental/svg/model/SkSVGDOM.cpp b/experimental/svg/model/SkSVGDOM.cpp
index f467c5e6d0..c9745f1730 100644
--- a/experimental/svg/model/SkSVGDOM.cpp
+++ b/experimental/svg/model/SkSVGDOM.cpp
@@ -384,26 +384,29 @@ sk_sp<SkSVGNode> construct_svg_node(const SkDOM& dom, const ConstructionContext&
 
 } // anonymous namespace
 
-SkSVGDOM::SkSVGDOM(const SkSize& containerSize)
-    : fContainerSize(containerSize) {
+SkSVGDOM::SkSVGDOM()
+    : fContainerSize(SkSize::Make(0, 0)) {
 }
 
-sk_sp<SkSVGDOM> SkSVGDOM::MakeFromDOM(const SkDOM& xmlDom, const SkSize& containerSize) {
-    sk_sp<SkSVGDOM> dom = sk_make_sp<SkSVGDOM>(containerSize);
+sk_sp<SkSVGDOM> SkSVGDOM::MakeFromDOM(const SkDOM& xmlDom) {
+    sk_sp<SkSVGDOM> dom = sk_make_sp<SkSVGDOM>();
 
     ConstructionContext ctx(&dom->fIDMapper);
     dom->fRoot = construct_svg_node(xmlDom, ctx, xmlDom.getRootNode());
 
+    // Reset the default container size to match the intrinsic SVG size.
+    dom->setContainerSize(dom->intrinsicSize());
+
     return dom;
 }
 
-sk_sp<SkSVGDOM> SkSVGDOM::MakeFromStream(SkStream& svgStream, const SkSize& containerSize) {
+sk_sp<SkSVGDOM> SkSVGDOM::MakeFromStream(SkStream& svgStream) {
     SkDOM xmlDom;
     if (!xmlDom.build(svgStream)) {
         return nullptr;
     }
 
-    return MakeFromDOM(xmlDom, containerSize);
+    return MakeFromDOM(xmlDom);
 }
 
 void SkSVGDOM::render(SkCanvas* canvas) const {
@@ -416,6 +419,20 @@ void SkSVGDOM::render(SkCanvas* canvas) const {
     }
 }
 
+SkSize SkSVGDOM::intrinsicSize() const {
+    if (!fRoot || fRoot->tag() != SkSVGTag::kSvg) {
+        return SkSize::Make(0, 0);
+    }
+
+    // Intrinsic sizes are never relative, so the viewport size is irrelevant.
+    const SkSVGLengthContext lctx(SkSize::Make(0, 0));
+    return static_cast<const SkSVGSVG*>(fRoot.get())->intrinsicSize(lctx);
+}
+
+const SkSize& SkSVGDOM::containerSize() const {
+    return fContainerSize;
+}
+
 void SkSVGDOM::setContainerSize(const SkSize& containerSize) {
     // TODO: inval
     fContainerSize = containerSize;
diff --git a/experimental/svg/model/SkSVGDOM.h b/experimental/svg/model/SkSVGDOM.h
index 9c59b7c561..8904c1799d 100644
--- a/experimental/svg/model/SkSVGDOM.h
+++ b/experimental/svg/model/SkSVGDOM.h
@@ -20,18 +20,22 @@ class SkSVGNode;
 
 class SkSVGDOM : public SkRefCnt {
 public:
-    SkSVGDOM(const SkSize& containerSize);
+    SkSVGDOM();
     ~SkSVGDOM() = default;
 
-    static sk_sp<SkSVGDOM> MakeFromDOM(const SkDOM&, const SkSize& containerSize);
-    static sk_sp<SkSVGDOM> MakeFromStream(SkStream&, const SkSize& containerSize);
+    static sk_sp<SkSVGDOM> MakeFromDOM(const SkDOM&);
+    static sk_sp<SkSVGDOM> MakeFromStream(SkStream&);
 
+    const SkSize& containerSize() const;
     void setContainerSize(const SkSize&);
+
     void setRoot(sk_sp<SkSVGNode>);
 
     void render(SkCanvas*) const;
 
 private:
+    SkSize intrinsicSize() const;
+
     SkSize           fContainerSize;
     sk_sp<SkSVGNode> fRoot;
     SkSVGIDMapper    fIDMapper;
diff --git a/experimental/svg/model/SkSVGSVG.cpp b/experimental/svg/model/SkSVGSVG.cpp
index 13f18043c0..592992760a 100644
--- a/experimental/svg/model/SkSVGSVG.cpp
+++ b/experimental/svg/model/SkSVGSVG.cpp
@@ -95,3 +95,15 @@ void SkSVGSVG::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
         this->INHERITED::onSetAttribute(attr, v);
     }
 }
+
+// https://www.w3.org/TR/SVG/coords.html#IntrinsicSizing
+SkSize SkSVGSVG::intrinsicSize(const SkSVGLengthContext& lctx) const {
+    // Percentage values do not provide an intrinsic size.
+    if (fWidth.unit() == SkSVGLength::Unit::kPercentage ||
+        fHeight.unit() == SkSVGLength::Unit::kPercentage) {
+        return SkSize::Make(0, 0);
+    }
+
+    return SkSize::Make(lctx.resolve(fWidth, SkSVGLengthContext::LengthType::kHorizontal),
+                        lctx.resolve(fHeight, SkSVGLengthContext::LengthType::kVertical));
+}
diff --git a/experimental/svg/model/SkSVGSVG.h b/experimental/svg/model/SkSVGSVG.h
index ae4787cac3..675c83351f 100644
--- a/experimental/svg/model/SkSVGSVG.h
+++ b/experimental/svg/model/SkSVGSVG.h
@@ -12,6 +12,8 @@
 #include "SkSVGTypes.h"
 #include "SkTLazy.h"
 
+class SkSVGLengthContext;
+
 class SkSVGSVG : public SkSVGContainer {
 public:
     virtual ~SkSVGSVG() = default;
@@ -24,6 +26,8 @@ public:
     void setHeight(const SkSVGLength&);
     void setViewBox(const SkSVGViewBoxType&);
 
+    SkSize intrinsicSize(const SkSVGLengthContext&) const;
+
 protected:
     bool onPrepareToRender(SkSVGRenderContext*) const override;