Gradient for VectorDrawable's fill and stroke

Add ComplexColor interface for both GradientColor and ColorStateList.
Set up constant state, factory, theme attrs for GradientColor, while
refactoring the ColorStateList's similar code. (Functionality in CSL should
be the same).

Support themeing in both the root and item level in GradientColor.
For example, both startColor in <gradient> tag or color in <item> tag can
have theme color.
Add tests for both simple and complex cases with themeing etc.

Hook up the native VectorDrawable implementation using 2 extra JNI calls for
simplicity. Such calls only happen at inflate and applyTheme call.

b/22564318

Change-Id: Ibdc564ddb4a7ee0133c6141c4784782f0c93ce0e

2 files changed, 54 insertions, 12 deletions

diff --git a/libs/hwui/VectorDrawable.cpp b/libs/hwui/VectorDrawable.cpp
index 1d31c9e08a9e..4d4acb94c255 100644
--- a/libs/hwui/VectorDrawable.cpp
+++ b/libs/hwui/VectorDrawable.cpp
@@ -18,6 +18,7 @@
 
 #include "PathParser.h"
 #include "SkImageInfo.h"
+#include "SkShader.h"
 #include <utils/Log.h>
 #include "utils/Macros.h"
 #include "utils/VectorDrawableUtils.h"
@@ -49,7 +50,7 @@ void Path::draw(SkCanvas* outCanvas, const SkMatrix& groupStackedMatrix, float s
 
     float minScale = fmin(scaleX, scaleY);
     float strokeScale = minScale * matrixScale;
-    drawPath(outCanvas, renderPath, strokeScale);
+    drawPath(outCanvas, renderPath, strokeScale, pathMatrix);
 }
 
 void Path::setPathData(const Data& data) {
@@ -148,6 +149,9 @@ FullPath::FullPath(const FullPath& path) : Path(path) {
     mStrokeMiterLimit = path.mStrokeMiterLimit;
     mStrokeLineCap = path.mStrokeLineCap;
     mStrokeLineJoin = path.mStrokeLineJoin;
+
+    SkRefCnt_SafeAssign(mStrokeGradient, path.mStrokeGradient);
+    SkRefCnt_SafeAssign(mFillGradient, path.mFillGradient);
 }
 
 const SkPath& FullPath::getUpdatedPath() {
@@ -186,22 +190,44 @@ inline SkColor applyAlpha(SkColor color, float alpha) {
     return SkColorSetA(color, alphaBytes * alpha);
 }
 
-void FullPath::drawPath(SkCanvas* outCanvas, const SkPath& renderPath, float strokeScale){
-    // Draw path's fill, if fill color isn't transparent.
-    if (mFillColor != SK_ColorTRANSPARENT) {
+void FullPath::drawPath(SkCanvas* outCanvas, const SkPath& renderPath, float strokeScale,
+                        const SkMatrix& matrix){
+    // Draw path's fill, if fill color or gradient is valid
+    bool needsFill = false;
+    if (mFillGradient != nullptr) {
+        mPaint.setColor(applyAlpha(SK_ColorBLACK, mFillAlpha));
+        SkShader* newShader = mFillGradient->newWithLocalMatrix(matrix);
+        mPaint.setShader(newShader);
+        needsFill = true;
+    } else if (mFillColor != SK_ColorTRANSPARENT) {
+        mPaint.setColor(applyAlpha(mFillColor, mFillAlpha));
+        outCanvas->drawPath(renderPath, mPaint);
+        needsFill = true;
+    }
+
+    if (needsFill) {
         mPaint.setStyle(SkPaint::Style::kFill_Style);
         mPaint.setAntiAlias(true);
-        mPaint.setColor(applyAlpha(mFillColor, mFillAlpha));
         outCanvas->drawPath(renderPath, mPaint);
     }
-    // Draw path's stroke, if stroke color isn't transparent
-    if (mStrokeColor != SK_ColorTRANSPARENT) {
+
+    // Draw path's stroke, if stroke color or gradient is valid
+    bool needsStroke = false;
+    if (mStrokeGradient != nullptr) {
+        mPaint.setColor(applyAlpha(SK_ColorBLACK, mStrokeAlpha));
+        SkShader* newShader = mStrokeGradient->newWithLocalMatrix(matrix);
+        mPaint.setShader(newShader);
+        needsStroke = true;
+    } else if (mStrokeColor != SK_ColorTRANSPARENT) {
+        mPaint.setColor(applyAlpha(mStrokeColor, mStrokeAlpha));
+        needsStroke = true;
+    }
+    if (needsStroke) {
         mPaint.setStyle(SkPaint::Style::kStroke_Style);
         mPaint.setAntiAlias(true);
         mPaint.setStrokeJoin(mStrokeLineJoin);
         mPaint.setStrokeCap(mStrokeLineCap);
         mPaint.setStrokeMiter(mStrokeMiterLimit);
-        mPaint.setColor(applyAlpha(mStrokeColor, mStrokeAlpha));
         mPaint.setStrokeWidth(mStrokeWidth * strokeScale);
         outCanvas->drawPath(renderPath, mPaint);
     }
@@ -288,7 +314,7 @@ bool FullPath::getProperties(int8_t* outProperties, int length) {
 }
 
 void ClipPath::drawPath(SkCanvas* outCanvas, const SkPath& renderPath,
-        float strokeScale){
+        float strokeScale, const SkMatrix& matrix){
     outCanvas->clipPath(renderPath, SkRegion::kIntersect_Op);
 }
 
diff --git a/libs/hwui/VectorDrawable.h b/libs/hwui/VectorDrawable.h
index 5ae5f6a3bdba..09bdce596a21 100644
--- a/libs/hwui/VectorDrawable.h
+++ b/libs/hwui/VectorDrawable.h
@@ -26,6 +26,7 @@
 #include <SkPath.h>
 #include <SkPathMeasure.h>
 #include <SkRect.h>
+#include <SkShader.h>
 
 #include <cutils/compiler.h>
 #include <stddef.h>
@@ -95,7 +96,7 @@ public:
 protected:
     virtual const SkPath& getUpdatedPath();
     virtual void drawPath(SkCanvas *outCanvas, const SkPath& renderPath,
-            float strokeScale) = 0;
+            float strokeScale, const SkMatrix& matrix) = 0;
     Data mData;
     SkPath mSkPath;
     bool mSkPathDirty = true;
@@ -108,6 +109,11 @@ public:
     FullPath() : Path() {}
     FullPath(const Data& nodes) : Path(nodes) {}
 
+    ~FullPath() {
+        SkSafeUnref(mFillGradient);
+        SkSafeUnref(mStrokeGradient);
+    }
+
     void updateProperties(float strokeWidth, SkColor strokeColor,
             float strokeAlpha, SkColor fillColor, float fillAlpha,
             float trimPathStart, float trimPathEnd, float trimPathOffset,
@@ -162,10 +168,18 @@ public:
     }
     bool getProperties(int8_t* outProperties, int length);
 
+    void setFillGradient(SkShader* fillGradient) {
+        SkRefCnt_SafeAssign(mFillGradient, fillGradient);
+    };
+    void setStrokeGradient(SkShader* strokeGradient) {
+        SkRefCnt_SafeAssign(mStrokeGradient, strokeGradient);
+    };
+
+
 protected:
     const SkPath& getUpdatedPath() override;
     void drawPath(SkCanvas* outCanvas, const SkPath& renderPath,
-            float strokeScale) override;
+            float strokeScale, const SkMatrix& matrix) override;
 
 private:
     // Applies trimming to the specified path.
@@ -174,6 +188,8 @@ private:
     SkColor mStrokeColor = SK_ColorTRANSPARENT;
     float mStrokeAlpha = 1;
     SkColor mFillColor = SK_ColorTRANSPARENT;
+    SkShader* mStrokeGradient = nullptr;
+    SkShader* mFillGradient = nullptr;
     float mFillAlpha = 1;
     float mTrimPathStart = 0;
     float mTrimPathEnd = 1;
@@ -195,7 +211,7 @@ public:
 
 protected:
     void drawPath(SkCanvas* outCanvas, const SkPath& renderPath,
-            float strokeScale) override;
+            float strokeScale, const SkMatrix& matrix) override;
 };
 
 class ANDROID_API Group: public Node {