[SVGDom] Initial linear gradient support

Kind of a big change, to connect several new bits into something useful:

  * ID tracking & lookup
  * new asPaint() node virtual to support shader (and in the future filter) based paint servers
  * <defs>, <linearGradient> and <stop> element support
  * 'href', 'offset', 'stop-color', 'stop-opacity' attribute support
  * IRI/FuncIRI and rgb(...) parsing

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003

Review-Url: https://codereview.chromium.org/2327233003

1 files changed, 49 insertions, 0 deletions

diff --git a/experimental/svg/model/SkSVGLinearGradient.h b/experimental/svg/model/SkSVGLinearGradient.h
new file mode 100644
index 0000000000..1a2e332baf
--- /dev/null
+++ b/experimental/svg/model/SkSVGLinearGradient.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSVGLinearGradient_DEFINED
+#define SkSVGLinearGradient_DEFINED
+
+#include "SkSVGHiddenContainer.h"
+#include "SkSVGTypes.h"
+
+class SkSVGLinearGradient : public SkSVGHiddenContainer {
+public:
+    virtual ~SkSVGLinearGradient() = default;
+    static sk_sp<SkSVGLinearGradient> Make() {
+        return sk_sp<SkSVGLinearGradient>(new SkSVGLinearGradient());
+    }
+
+    void setHref(const SkSVGStringType&);
+    void setX1(const SkSVGLength&);
+    void setY1(const SkSVGLength&);
+    void setX2(const SkSVGLength&);
+    void setY2(const SkSVGLength&);
+
+protected:
+    bool onAsPaint(const SkSVGRenderContext&, SkPaint*) const override;
+
+    void onSetAttribute(SkSVGAttribute, const SkSVGValue&) override;
+
+private:
+    SkSVGLinearGradient();
+
+    void collectColorStops(const SkSVGRenderContext&,
+                           SkSTArray<2, SkScalar, true>*,
+                           SkSTArray<2, SkColor, true>*) const;
+
+    SkSVGLength fX1 = SkSVGLength(0  , SkSVGLength::Unit::kPercentage);
+    SkSVGLength fY1 = SkSVGLength(0  , SkSVGLength::Unit::kPercentage);
+    SkSVGLength fX2 = SkSVGLength(100, SkSVGLength::Unit::kPercentage);
+    SkSVGLength fY2 = SkSVGLength(0  , SkSVGLength::Unit::kPercentage);
+
+    SkSVGStringType fHref;
+
+    typedef SkSVGHiddenContainer INHERITED;
+};
+
+#endif // SkSVGLinearGradient_DEFINED