Allow SkCanvas to be initialized to force conservative rasterclips. This has the following effects:

1. Queries to the current clip will be conservatively large. This can mean the quickReject may return false more often.

2. The conservative clips mean less work is done.

3. Enabled by default for Gpu, Record, and NoSaveLayer canvases.

4. API is private for now.

R=robertphillips@google.com, bsalomon@google.com, mtklein@google.com, junov@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/541593005

4 files changed, 16 insertions, 22 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index f514d18b5e..5088d7ded5 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -1265,11 +1265,6 @@ protected:
                         SkIRect* intersection,
                         const SkImageFilter* imageFilter = NULL);
 
-    // Called by child classes that override clipPath and clipRRect to only
-    // track fast conservative clip bounds, rather than exact clips.
-    void updateClipConservativelyUsingBounds(const SkRect&, SkRegion::Op,
-                                             bool inverseFilled);
-
     // notify our surface (if we have one) that we are about to draw, so it
     // can perform copy-on-write or invalidate any cached images
     void predrawNotify();
@@ -1309,13 +1304,22 @@ private:
     friend class SkDebugCanvas;     // needs experimental fAllowSimplifyClip
     friend class SkDeferredDevice;  // needs getTopDevice()
     friend class SkSurface_Raster;  // needs getDevice()
+    friend class SkRecorder;        // InitFlags
+    friend class SkNoSaveLayerCanvas;   // InitFlags
     
+    enum InitFlags {
+        kDefault_InitFlags                  = 0,
+        kConservativeRasterClip_InitFlag    = 1 << 0,
+    };
+    SkCanvas(int width, int height, InitFlags flags);
+    SkCanvas(SkBaseDevice*, InitFlags flags);
+
     // needs gettotalclip()
     friend SkCanvasState* SkCanvasStateUtils::CaptureCanvasState(SkCanvas*);
     
     SkBaseDevice* createLayerDevice(const SkImageInfo&);
 
-    SkBaseDevice* init(SkBaseDevice*);
+    SkBaseDevice* init(SkBaseDevice*, InitFlags);
 
     /**
      *  DEPRECATED
@@ -1365,6 +1369,7 @@ private:
     mutable bool   fCachedLocalClipBoundsDirty;
     bool fAllowSoftClip;
     bool fAllowSimplifyClip;
+    bool fConservativeRasterClip;
 
     const SkRect& getLocalClipBounds() const {
         if (fCachedLocalClipBoundsDirty) {
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index aad5bf4737..618431a2de 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -372,6 +372,8 @@ private:
     // TODO: move to SkBitmapDevice
     virtual void replaceBitmapBackendForRasterSurface(const SkBitmap&) {}
 
+    virtual bool forceConservativeRasterClip() const { return false; }
+
     // just called by SkCanvas when built as a layer
     void setOrigin(int x, int y) { fOrigin.set(x, y); }
     // just called by SkCanvas for saveLayer
diff --git a/include/gpu/SkGpuDevice.h b/include/gpu/SkGpuDevice.h
index 91fc2f0bb6..5545227129 100644
--- a/include/gpu/SkGpuDevice.h
+++ b/include/gpu/SkGpuDevice.h
@@ -152,6 +152,7 @@ private:
     virtual SkSurface* newSurface(const SkImageInfo&) SK_OVERRIDE;
 
     virtual SkImageFilter::Cache* getImageFilterCache() SK_OVERRIDE;
+    virtual bool forceConservativeRasterClip() const SK_OVERRIDE { return true; }
 
     // sets the render target, clip, and matrix on GrContext. Use forceIdenity to override
     // SkDraw's matrix and draw in device coords.
diff --git a/include/utils/SkNoSaveLayerCanvas.h b/include/utils/SkNoSaveLayerCanvas.h
index 686f179901..56a09622a0 100644
--- a/include/utils/SkNoSaveLayerCanvas.h
+++ b/include/utils/SkNoSaveLayerCanvas.h
@@ -16,7 +16,8 @@
 // It also simplifies the clipping calls to only use rectangles.
 class SK_API SkNoSaveLayerCanvas : public SkCanvas {
 public:
-    SkNoSaveLayerCanvas(SkBaseDevice* device) : INHERITED(device) {}
+    SkNoSaveLayerCanvas(SkBaseDevice* device) : INHERITED(device, kConservativeRasterClip_InitFlag)
+    {}
 
 protected:
     virtual SaveLayerStrategy willSaveLayer(const SkRect* bounds, const SkPaint* paint,
@@ -25,21 +26,6 @@ protected:
         return kNoLayer_SaveLayerStrategy;
     }
 
-    // disable aa for speed
-    virtual void onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle) SK_OVERRIDE {
-        this->INHERITED::onClipRect(rect, op, kHard_ClipEdgeStyle);
-    }
-
-    // for speed, just respect the bounds, and disable AA. May give us a few
-    // false positives and negatives.
-    virtual void onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle) SK_OVERRIDE {
-        this->updateClipConservativelyUsingBounds(path.getBounds(), op,
-                                                  path.isInverseFillType());
-    }
-    virtual void onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyle) SK_OVERRIDE {
-        this->updateClipConservativelyUsingBounds(rrect.getBounds(), op, false);
-    }
-
 private:
     typedef SkCanvas INHERITED;
 };