[SVGDom] Radial gradient support

Implement support for
https://www.w3.org/TR/SVG/pservers.html#RadialGradients.

BUG=skia:7074

Change-Id: I19645a4a3bbddfd1ee0d08a2775381a0017acbfc
Reviewed-on: https://skia-review.googlesource.com/57340
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Robert Phillips <robertphillips@google.com>

5 files changed, 142 insertions, 3 deletions

diff --git a/experimental/svg/model/SkSVGAttribute.h b/experimental/svg/model/SkSVGAttribute.h
index 2900a03f7c..084fcc0290 100644
--- a/experimental/svg/model/SkSVGAttribute.h
+++ b/experimental/svg/model/SkSVGAttribute.h
@@ -15,19 +15,21 @@ class SkSVGRenderContext;
 
 enum class SkSVGAttribute {
     kClipPath,
-    kCx, // <circle>,<ellipse>: center x position
-    kCy, // <circle>,<ellipse>: center y position
+    kCx, // <circle>, <ellipse>, <radialGradient>: center x position
+    kCy, // <circle>, <ellipse>, <radialGradient>: center y position
     kD,
     kFill,
     kFillOpacity,
     kFillRule,
+    kFx, // <radialGradient>: focal point x position
+    kFy, // <radialGradient>: focal point y position
     kGradientTransform,
     kHeight,
     kHref,
     kOffset,
     kOpacity,
     kPoints,
-    kR,  // <circle>: radius
+    kR,  // <circle>, <radialGradient>: radius
     kRx, // <ellipse>,<rect>: horizontal (corner) radius
     kRy, // <ellipse>,<rect>: vertical (corner) radius
     kSpreadMethod,
diff --git a/experimental/svg/model/SkSVGDOM.cpp b/experimental/svg/model/SkSVGDOM.cpp
index a67576b40c..2640399f9c 100644
--- a/experimental/svg/model/SkSVGDOM.cpp
+++ b/experimental/svg/model/SkSVGDOM.cpp
@@ -21,6 +21,7 @@
 #include "SkSVGNode.h"
 #include "SkSVGPath.h"
 #include "SkSVGPoly.h"
+#include "SkSVGRadialGradient.h"
 #include "SkSVGRect.h"
 #include "SkSVGRenderContext.h"
 #include "SkSVGStop.h"
@@ -284,6 +285,9 @@ SortedDictionaryEntry<AttrParseInfo> gAttributeParseInfo[] = {
     { "fill"             , { SkSVGAttribute::kFill             , SetPaintAttribute        }},
     { "fill-opacity"     , { SkSVGAttribute::kFillOpacity      , SetNumberAttribute       }},
     { "fill-rule"        , { SkSVGAttribute::kFillRule         , SetFillRuleAttribute     }},
+    // focal point x & y
+    { "fx"               , { SkSVGAttribute::kFx               , SetLengthAttribute       }},
+    { "fy"               , { SkSVGAttribute::kFy               , SetLengthAttribute       }},
     { "gradientTransform", { SkSVGAttribute::kGradientTransform, SetTransformAttribute    }},
     { "height"           , { SkSVGAttribute::kHeight           , SetLengthAttribute       }},
     { "offset"           , { SkSVGAttribute::kOffset           , SetLengthAttribute       }},
@@ -324,6 +328,7 @@ SortedDictionaryEntry<sk_sp<SkSVGNode>(*)()> gTagFactories[] = {
     { "path"          , []() -> sk_sp<SkSVGNode> { return SkSVGPath::Make();           }},
     { "polygon"       , []() -> sk_sp<SkSVGNode> { return SkSVGPoly::MakePolygon();    }},
     { "polyline"      , []() -> sk_sp<SkSVGNode> { return SkSVGPoly::MakePolyline();   }},
+    { "radialGradient", []() -> sk_sp<SkSVGNode> { return SkSVGRadialGradient::Make(); }},
     { "rect"          , []() -> sk_sp<SkSVGNode> { return SkSVGRect::Make();           }},
     { "stop"          , []() -> sk_sp<SkSVGNode> { return SkSVGStop::Make();           }},
     { "svg"           , []() -> sk_sp<SkSVGNode> { return SkSVGSVG::Make();            }},
diff --git a/experimental/svg/model/SkSVGNode.h b/experimental/svg/model/SkSVGNode.h
index 385b1584b8..86c98d3064 100644
--- a/experimental/svg/model/SkSVGNode.h
+++ b/experimental/svg/model/SkSVGNode.h
@@ -29,6 +29,7 @@ enum class SkSVGTag {
     kPath,
     kPolygon,
     kPolyline,
+    kRadialGradient,
     kRect,
     kStop,
     kSvg
diff --git a/experimental/svg/model/SkSVGRadialGradient.cpp b/experimental/svg/model/SkSVGRadialGradient.cpp
new file mode 100644
index 0000000000..c719693a06
--- /dev/null
+++ b/experimental/svg/model/SkSVGRadialGradient.cpp
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkGradientShader.h"
+#include "SkSVGRadialGradient.h"
+#include "SkSVGRenderContext.h"
+#include "SkSVGValue.h"
+
+SkSVGRadialGradient::SkSVGRadialGradient() : INHERITED(SkSVGTag::kRadialGradient) {}
+
+void SkSVGRadialGradient::setCx(const SkSVGLength& cx) {
+    fCx = cx;
+}
+
+void SkSVGRadialGradient::setCy(const SkSVGLength& cy) {
+    fCy = cy;
+}
+
+void SkSVGRadialGradient::setR(const SkSVGLength& r) {
+    fR = r;
+}
+
+void SkSVGRadialGradient::setFx(const SkSVGLength& fx) {
+    fFx.set(fx);
+}
+
+void SkSVGRadialGradient::setFy(const SkSVGLength& fy) {
+    fFy.set(fy);
+}
+
+void SkSVGRadialGradient::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
+    switch (attr) {
+    case SkSVGAttribute::kCx:
+        if (const auto* cx = v.as<SkSVGLengthValue>()) {
+            this->setCx(*cx);
+        }
+        break;
+    case SkSVGAttribute::kCy:
+        if (const auto* cy = v.as<SkSVGLengthValue>()) {
+            this->setCy(*cy);
+        }
+        break;
+    case SkSVGAttribute::kR:
+        if (const auto* r = v.as<SkSVGLengthValue>()) {
+            this->setR(*r);
+        }
+        break;
+    case SkSVGAttribute::kFx:
+        if (const auto* fx = v.as<SkSVGLengthValue>()) {
+            this->setFx(*fx);
+        }
+        break;
+    case SkSVGAttribute::kFy:
+        if (const auto* fy = v.as<SkSVGLengthValue>()) {
+            this->setFy(*fy);
+        }
+        break;
+    default:
+        this->INHERITED::onSetAttribute(attr, v);
+    }
+}
+
+sk_sp<SkShader> SkSVGRadialGradient::onMakeShader(const SkSVGRenderContext& ctx,
+                                                  const SkColor* colors, const SkScalar* pos,
+                                                  int count, SkShader::TileMode tm,
+                                                  const SkMatrix& m) const {
+    const auto&  lctx = ctx.lengthContext();
+    const auto      r = lctx.resolve(fR , SkSVGLengthContext::LengthType::kOther);
+    const auto center = SkPoint::Make(
+            lctx.resolve(fCx, SkSVGLengthContext::LengthType::kHorizontal),
+            lctx.resolve(fCy, SkSVGLengthContext::LengthType::kVertical));
+    const auto  focal = SkPoint::Make(
+        fFx.isValid() ? lctx.resolve(*fFx.get(), SkSVGLengthContext::LengthType::kHorizontal)
+                      : center.x(),
+        fFy.isValid() ? lctx.resolve(*fFy.get(), SkSVGLengthContext::LengthType::kVertical)
+                      : center.y());
+
+    return center == focal
+        ? SkGradientShader::MakeRadial(center, r, colors, pos, count, tm, 0, &m)
+        : SkGradientShader::MakeTwoPointConical(focal, 0, center, r, colors, pos, count, tm, 0, &m);
+}
diff --git a/experimental/svg/model/SkSVGRadialGradient.h b/experimental/svg/model/SkSVGRadialGradient.h
new file mode 100644
index 0000000000..f277b65cc3
--- /dev/null
+++ b/experimental/svg/model/SkSVGRadialGradient.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSVGRadialGradient_DEFINED
+#define SkSVGRadialGradient_DEFINED
+
+#include "SkSVGGradient.h"
+#include "SkSVGTypes.h"
+
+class SkSVGRadialGradient final : public SkSVGGradient {
+public:
+    ~SkSVGRadialGradient() override = default;
+    static sk_sp<SkSVGRadialGradient> Make() {
+        return sk_sp<SkSVGRadialGradient>(new SkSVGRadialGradient());
+    }
+
+    void setCx(const SkSVGLength&);
+    void setCy(const SkSVGLength&);
+    void setR(const SkSVGLength&);
+    void setFx(const SkSVGLength&);
+    void setFy(const SkSVGLength&);
+
+protected:
+    void onSetAttribute(SkSVGAttribute, const SkSVGValue&) override;
+
+    sk_sp<SkShader> onMakeShader(const SkSVGRenderContext&,
+                                 const SkColor*, const SkScalar*, int count,
+                                 SkShader::TileMode, const SkMatrix&) const override;
+private:
+    SkSVGRadialGradient();
+
+    SkSVGLength fCx = SkSVGLength(50, SkSVGLength::Unit::kPercentage);
+    SkSVGLength fCy = SkSVGLength(50, SkSVGLength::Unit::kPercentage);
+    SkSVGLength fR  = SkSVGLength(50, SkSVGLength::Unit::kPercentage);
+    SkTLazy<SkSVGLength> fFx;
+    SkTLazy<SkSVGLength> fFy;
+
+
+   typedef SkSVGGradient INHERITED;
+};
+
+#endif // SkSVGRadialGradient_DEFINED