[SVGDom] Add viewBox support

The main feature is <svg> viewBox and proper viewport support, but the CL
touches a few other things:

* refactor SkSVGRenderContext to auto-restore canvas state, and split the
  presentation bits into a separate CoW SkSVGPresentationContext

* introduce SkSVGNode::onPrepareToRender(), as a way for nodes to push their
  custom state before the actual onRender() call (instead of relying on
  non-virtual SkSVGNode to know about all possible state bits)

* add a "Type" suffix to SVG types, to disambiguate (e.g. SkSVGRectType vs.
  SkSVGRect)

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2222793002

Review-Url: https://codereview.chromium.org/2222793002

1 files changed, 18 insertions, 3 deletions

diff --git a/experimental/svg/model/SkSVGDOM.cpp b/experimental/svg/model/SkSVGDOM.cpp
index df589230e0..13d67b9cfe 100644
--- a/experimental/svg/model/SkSVGDOM.cpp
+++ b/experimental/svg/model/SkSVGDOM.cpp
@@ -73,7 +73,7 @@ SkMatrix ParseTransform(const char* str) {
 
 bool SetPaintAttribute(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr,
                        const char* stringValue) {
-    SkSVGColor color;
+    SkSVGColorType color;
     SkSVGAttributeParser parser(stringValue);
     if (!parser.parseColor(&color)) {
         return false;
@@ -112,6 +112,18 @@ bool SetLengthAttribute(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr,
     return true;
 }
 
+bool SetViewBoxAttribute(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr,
+                         const char* stringValue) {
+    SkSVGViewBoxType viewBox;
+    SkSVGAttributeParser parser(stringValue);
+    if (!parser.parseViewBox(&viewBox)) {
+        return false;
+    }
+
+    node->setAttribute(attr, SkSVGViewBoxValue(viewBox));
+    return true;
+}
+
 // Breaks a "foo: bar; baz: ..." string into key:value pairs.
 class StyleIterator {
 public:
@@ -184,6 +196,7 @@ SortedDictionaryEntry<AttrParseInfo> gAttributeParseInfo[] = {
     { "stroke"   , { SkSVGAttribute::kStroke   , SetPaintAttribute     }},
     { "style"    , { SkSVGAttribute::kUnknown  , SetStyleAttributes    }},
     { "transform", { SkSVGAttribute::kTransform, SetTransformAttribute }},
+    { "viewBox"  , { SkSVGAttribute::kViewBox  , SetViewBoxAttribute   }},
     { "width"    , { SkSVGAttribute::kWidth    , SetLengthAttribute    }},
     { "x"        , { SkSVGAttribute::kX        , SetLengthAttribute    }},
     { "y"        , { SkSVGAttribute::kY        , SetLengthAttribute    }},
@@ -292,8 +305,10 @@ sk_sp<SkSVGDOM> SkSVGDOM::MakeFromStream(SkStream& svgStream, const SkSize& cont
 
 void SkSVGDOM::render(SkCanvas* canvas) const {
     if (fRoot) {
-        SkSVGRenderContext ctx(fContainerSize);
-        fRoot->render(canvas, ctx);
+        SkSVGRenderContext ctx(canvas,
+                               SkSVGLengthContext(fContainerSize),
+                               SkSVGPresentationContext());
+        fRoot->render(ctx);
     }
 }