add arcto patheffect

BUG=skia:
TBR=

Review URL: https://codereview.chromium.org/813513003

6 files changed, 159 insertions, 20 deletions

diff --git a/gyp/effects.gypi b/gyp/effects.gypi
index c82d886318..88d5d1a842 100644
--- a/gyp/effects.gypi
+++ b/gyp/effects.gypi
@@ -10,6 +10,7 @@
     '<(skia_src_path)/effects/Sk1DPathEffect.cpp',
     '<(skia_src_path)/effects/Sk2DPathEffect.cpp',
     '<(skia_src_path)/effects/SkAlphaThresholdFilter.cpp',
+    '<(skia_src_path)/effects/SkArcToPathEffect.cpp',
     '<(skia_src_path)/effects/SkArithmeticMode.cpp',
     '<(skia_src_path)/effects/SkAvoidXfermode.cpp',
     '<(skia_src_path)/effects/SkBitmapSource.cpp',
diff --git a/include/effects/SkArcToPathEffect.h b/include/effects/SkArcToPathEffect.h
new file mode 100644
index 0000000000..6b6e2c721c
--- /dev/null
+++ b/include/effects/SkArcToPathEffect.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkArcToPathEffect_DEFINED
+#define SkArcToPathEffect_DEFINED
+
+#include "SkPathEffect.h"
+
+class SK_API SkArcToPathEffect : public SkPathEffect {
+public:
+    /** radius must be > 0 to have an effect. It specifies the distance from each corner
+        that should be "rounded".
+    */
+    static SkPathEffect* Create(SkScalar radius) {
+        if (radius <= 0) {
+            return NULL;
+        }
+        return SkNEW_ARGS(SkArcToPathEffect, (radius));
+    }
+
+    bool filterPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect*) const SK_OVERRIDE;
+
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkArcToPathEffect)
+
+protected:
+    explicit SkArcToPathEffect(SkScalar radius);
+    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+
+private:
+    SkScalar fRadius;
+
+    typedef SkPathEffect INHERITED;
+};
+
+#endif
diff --git a/samplecode/SamplePath.cpp b/samplecode/SamplePath.cpp
index 49c51d3ad0..14aae8285c 100644
--- a/samplecode/SamplePath.cpp
+++ b/samplecode/SamplePath.cpp
@@ -214,45 +214,56 @@ DEF_SAMPLE( return new PathView; )
 
 //////////////////////////////////////////////////////////////////////////////
 
+#include "SkArcToPathEffect.h"
 #include "SkCornerPathEffect.h"
 #include "SkRandom.h"
 
 class ArcToView : public SampleView {
-    SkPaint fPtsPaint, fArcPaint, fSkeletonPaint, fCornerPaint;
+    bool fDoFrame, fDoArcTo, fDoCorner, fDoConic;
+    SkPaint fPtsPaint, fArcToPaint, fSkeletonPaint, fCornerPaint;
 public:
     enum {
         N = 4
     };
     SkPoint fPts[N];
-    SkScalar fRadius;
 
-    ArcToView() : fRadius(50) {
+    ArcToView()
+        : fDoFrame(false), fDoArcTo(false), fDoCorner(false), fDoConic(false)
+    {
         SkRandom rand;
         for (int i = 0; i < N; ++i) {
             fPts[i].fX = 20 + rand.nextUScalar1() * 640;
             fPts[i].fY = 20 + rand.nextUScalar1() * 480;
         }
+        
+        const SkScalar rad = 50;
 
         fPtsPaint.setAntiAlias(true);
         fPtsPaint.setStrokeWidth(15);
         fPtsPaint.setStrokeCap(SkPaint::kRound_Cap);
 
-        fArcPaint.setAntiAlias(true);
-        fArcPaint.setStyle(SkPaint::kStroke_Style);
-        fArcPaint.setStrokeWidth(9);
-        fArcPaint.setColor(0x800000FF);
+        fArcToPaint.setAntiAlias(true);
+        fArcToPaint.setStyle(SkPaint::kStroke_Style);
+        fArcToPaint.setStrokeWidth(9);
+        fArcToPaint.setColor(0x800000FF);
+        fArcToPaint.setPathEffect(SkArcToPathEffect::Create(rad))->unref();
 
         fCornerPaint.setAntiAlias(true);
         fCornerPaint.setStyle(SkPaint::kStroke_Style);
         fCornerPaint.setStrokeWidth(13);
         fCornerPaint.setColor(SK_ColorGREEN);
-        fCornerPaint.setPathEffect(SkCornerPathEffect::Create(fRadius*2))->unref();
+        fCornerPaint.setPathEffect(SkCornerPathEffect::Create(rad*2))->unref();
 
         fSkeletonPaint.setAntiAlias(true);
         fSkeletonPaint.setStyle(SkPaint::kStroke_Style);
         fSkeletonPaint.setColor(SK_ColorRED);
     }
 
+    void toggle(bool& value) {
+        value = !value;
+        this->inval(NULL);
+    }
+
 protected:
     // overrides from SkEventSink
     bool onQuery(SkEvent* evt) SK_OVERRIDE {
@@ -260,29 +271,43 @@ protected:
             SampleCode::TitleR(evt, "ArcTo");
             return true;
         }
+        SkUnichar uni;
+        if (SampleCode::CharQ(*evt, &uni)) {
+            switch (uni) {
+                case '1': this->toggle(fDoFrame); return true;
+                case '2': this->toggle(fDoArcTo); return true;
+                case '3': this->toggle(fDoCorner); return true;
+                case '4': this->toggle(fDoConic); return true;
+                default: break;
+            }
+        }
         return this->INHERITED::onQuery(evt);
     }
+    
+    void makePath(SkPath* path) {
+        path->moveTo(fPts[0]);
+        for (int i = 1; i < N; ++i) {
+            path->lineTo(fPts[i]);
+        }
+        if (!fDoFrame) {
+            path->close();
+        }
+    }
 
     void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
         canvas->drawPoints(SkCanvas::kPoints_PointMode, N, fPts, fPtsPaint);
 
         SkPath path;
+        this->makePath(&path);
 
-        path.moveTo(fPts[0]);
-        for (int i = 1; i < N; ++i) {
-            path.lineTo(fPts[i].fX, fPts[i].fY);
+        if (fDoCorner) {
+            canvas->drawPath(path, fCornerPaint);
         }
-        canvas->drawPath(path, fCornerPaint);
-
-        path.reset();
-        path.moveTo(fPts[0]);
-        for (int i = 1; i < N - 1; ++i) {
-            path.arcTo(fPts[i].fX, fPts[i].fY, fPts[i+1].fX, fPts[i+1].fY, fRadius);
+        if (fDoArcTo) {
+            canvas->drawPath(path, fArcToPaint);
         }
-        path.lineTo(fPts[N - 1]);
-        canvas->drawPath(path, fArcPaint);
 
-        canvas->drawPoints(SkCanvas::kPolygon_PointMode, N, fPts, fSkeletonPaint);
+        canvas->drawPath(path, fSkeletonPaint);
     }
 
     bool onClick(Click* click) SK_OVERRIDE {
diff --git a/src/effects/SkArcToPathEffect.cpp b/src/effects/SkArcToPathEffect.cpp
new file mode 100644
index 0000000000..79398b3b82
--- /dev/null
+++ b/src/effects/SkArcToPathEffect.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkArcToPathEffect.h"
+#include "SkPath.h"
+#include "SkPoint.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+
+SkArcToPathEffect::SkArcToPathEffect(SkScalar radius) : fRadius(radius) {}
+
+bool SkArcToPathEffect::filterPath(SkPath* dst, const SkPath& src,
+                                   SkStrokeRec*, const SkRect*) const {
+    SkPath::Iter    iter(src, false);
+    SkPath::Verb    verb;
+    SkPoint         pts[4];
+
+    SkPoint         lastCorner = { 0, 0 }; // avoid warning
+    SkPath::Verb    prevVerb = SkPath::kMove_Verb;
+
+    for (;;) {
+        switch (verb = iter.next(pts, false)) {
+            case SkPath::kMove_Verb:
+                if (SkPath::kLine_Verb == prevVerb) {
+                    dst->lineTo(lastCorner);
+                }
+                dst->moveTo(pts[0]);
+                break;
+            case SkPath::kLine_Verb:
+                if (prevVerb == SkPath::kLine_Verb) {
+                    dst->arcTo(pts[0], pts[1], fRadius);
+                }
+                lastCorner = pts[1];
+                break;
+            case SkPath::kQuad_Verb:
+                dst->quadTo(pts[1], pts[2]);
+                lastCorner = pts[2];
+                break;
+            case SkPath::kConic_Verb:
+                dst->conicTo(pts[1], pts[2], iter.conicWeight());
+                lastCorner = pts[2];
+                break;
+            case SkPath::kCubic_Verb:
+                dst->cubicTo(pts[1], pts[2], pts[3]);
+                lastCorner = pts[3];
+                break;
+            case SkPath::kClose_Verb:
+                dst->lineTo(lastCorner);
+                break;
+            case SkPath::kDone_Verb:
+                dst->lineTo(lastCorner);
+                goto DONE;
+        }
+        prevVerb = verb;
+    }
+DONE:
+    return true;
+}
+
+SkFlattenable* SkArcToPathEffect::CreateProc(SkReadBuffer& buffer) {
+    return SkArcToPathEffect::Create(buffer.readScalar());
+}
+
+void SkArcToPathEffect::flatten(SkWriteBuffer& buffer) const {
+    buffer.writeScalar(fRadius);
+}
diff --git a/src/ports/SkGlobalInitialization_chromium.cpp b/src/ports/SkGlobalInitialization_chromium.cpp
index 9f5614cb74..a5115d3df6 100644
--- a/src/ports/SkGlobalInitialization_chromium.cpp
+++ b/src/ports/SkGlobalInitialization_chromium.cpp
@@ -16,6 +16,7 @@
 #include "Sk1DPathEffect.h"
 #include "Sk2DPathEffect.h"
 #include "SkArithmeticMode.h"
+#include "SkArcToPathEffect.h"
 #include "SkAvoidXfermode.h"
 #include "SkBitmapSource.h"
 #include "SkBlurDrawLooper.h"
@@ -63,6 +64,7 @@
 class SkPrivateEffectInitializer {
 public:
     static void Init() {
+        SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArcToPathEffect)
         SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkAvoidXfermode)
         SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkBitmapProcShader)
         SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkBitmapSource)
diff --git a/src/ports/SkGlobalInitialization_default.cpp b/src/ports/SkGlobalInitialization_default.cpp
index 9f5614cb74..a5115d3df6 100644
--- a/src/ports/SkGlobalInitialization_default.cpp
+++ b/src/ports/SkGlobalInitialization_default.cpp
@@ -16,6 +16,7 @@
 #include "Sk1DPathEffect.h"
 #include "Sk2DPathEffect.h"
 #include "SkArithmeticMode.h"
+#include "SkArcToPathEffect.h"
 #include "SkAvoidXfermode.h"
 #include "SkBitmapSource.h"
 #include "SkBlurDrawLooper.h"
@@ -63,6 +64,7 @@
 class SkPrivateEffectInitializer {
 public:
     static void Init() {
+        SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArcToPathEffect)
         SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkAvoidXfermode)
         SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkBitmapProcShader)
         SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkBitmapSource)