Sky: Allow clients to specify tile mode for gradients (repeating or mirror).

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1166223004.

engine/core/painting/CanvasGradient.cpp

@@ -13,9 +13,11 @@ PassRefPtr<CanvasGradient> CanvasGradient::create() {
 
 void CanvasGradient::initLinear(const Vector<Point>& end_points,
                                 const Vector<SkColor>& colors,
-                                const Vector<float>& color_stops) {
+                                const Vector<float>& color_stops,
+                                unsigned tile_mode) {
   ASSERT(end_points.size() == 2);
   ASSERT(colors.size() == color_stops.size() || color_stops.data() == nullptr);
+  ASSERT(tile_mode < SkShader::kTileModeCount);
   SkPoint sk_end_points[2];
   for (int i = 0; i < 2; ++i)
     sk_end_points[i] = end_points[i].sk_point;
@@ -23,19 +25,21 @@ void CanvasGradient::initLinear(const Vector<Point>& end_points,
   // TODO(mpcomplete): allow setting the TileMode.
   SkShader* shader = SkGradientShader::CreateLinear(
       sk_end_points, colors.data(), color_stops.data(), colors.size(),
-      SkShader::kClamp_TileMode);
+      static_cast<SkShader::TileMode>(tile_mode));
   set_shader(adoptRef(shader));
 }
 
 void CanvasGradient::initRadial(const Point& center,
                                 double radius,
                                 const Vector<SkColor>& colors,
-                                const Vector<float>& color_stops) {
+                                const Vector<float>& color_stops,
+                                unsigned tile_mode) {
   ASSERT(colors.size() == color_stops.size() || color_stops.data() == nullptr);
+  ASSERT(tile_mode < SkShader::kTileModeCount);
 
   SkShader* shader = SkGradientShader::CreateRadial(
       center.sk_point, radius, colors.data(), color_stops.data(), colors.size(),
-      SkShader::kClamp_TileMode);
+      static_cast<SkShader::TileMode>(tile_mode));
   set_shader(adoptRef(shader));
 }
 

engine/core/painting/CanvasGradient.h

@@ -21,11 +21,13 @@ class CanvasGradient : public Shader {
 
   void initLinear(const Vector<Point>& end_points,
                   const Vector<SkColor>& colors,
-                  const Vector<float>& color_stops);
+                  const Vector<float>& color_stops,
+                  unsigned tile_mode);
   void initRadial(const Point& center,
                   double radius,
                   const Vector<SkColor>& colors,
-                  const Vector<float>& color_stops);
+                  const Vector<float>& color_stops,
+                  unsigned tile_mode);
 
  private:
   CanvasGradient();

engine/core/painting/Gradient.dart

@@ -4,26 +4,34 @@
 
 part of dart.sky;
 
+enum TileMode {
+  clamp,
+  repeated,
+  mirror
+}
+
 // Extends the generated _Gradient interface via the PrivateDart attribute.
 class Gradient extends _Gradient {
   // TODO(mpcomplete): Maybe pass a list of (color, colorStop) pairs instead?
   Gradient.Linear(List<Point> endPoints,
                   List<Color> colors,
-                  List<double> colorStops)
+                  List<double> colorStops,
+                  [TileMode tileMode = TileMode.clamp])
       : super() {
     if (endPoints == null || endPoints.length != 2)
       throw new ArgumentError("Expected exactly 2 [endPoints].");
     validateColorStops(colors, colorStops);
-    this._initLinear(endPoints, colors, colorStops);
+    this._initLinear(endPoints, colors, colorStops, tileMode.index);
   }
 
   Gradient.Radial(Point center,
                   double radius,
                   List<Color> colors,
-                  List<double> colorStops)
+                  List<double> colorStops,
+                  [TileMode tileMode = TileMode.clamp])
       : super() {
     validateColorStops(colors, colorStops);
-    this._initRadial(center, radius, colors, colorStops);
+    this._initRadial(center, radius, colors, colorStops, tileMode.index);
   }
 
   void validateColorStops(List<Color> colors, List<double> colorStops) {

engine/core/painting/Gradient.idl

@@ -7,7 +7,8 @@
     PrivateDart,
     Constructor()
 ] interface Gradient : Shader {
-  void initLinear(Point[] endPoints, Color[] colors, float[] colorStops);
+  void initLinear(Point[] endPoints, Color[] colors, float[] colorStops,
+                  /*TileMode*/unsigned long tileMode);
   void initRadial(Point center, double radius, Color[] colors,
-                  float[] colorStops);
+                  float[] colorStops, /*TileMode*/unsigned long tileMode);
 };

examples/raw/painting.sky

@@ -68,9 +68,9 @@ void main() {
               ..setPaintBits(-1),
             (Paint layerPaint) {
           Gradient redYellow = new Gradient.Radial(
-              new Point(0.0, 0.0), radius,
+              new Point(0.0, 0.0), radius/3.0,
               [const Color(0xFFFFFF00), const Color(0xFFFF0000)],
-              null);
+              null, TileMode.mirror);
           layerPaint.setShader(redYellow);
         })
         ..addLayerOnTop(