Make Gr clear take a rect for a partial-clear

Review URL: http://codereview.appspot.com/4442093/



git-svn-id: http://skia.googlecode.com/svn/trunk@1203 2bbb7eff-a529-9590-31e7-b0007b416f81

5 files changed, 19 insertions, 11 deletions

diff --git a/gpu/include/GrContext.h b/gpu/include/GrContext.h
index 3112112ff8..214fc0543f 100644
--- a/gpu/include/GrContext.h
+++ b/gpu/include/GrContext.h
@@ -282,9 +282,11 @@ public:
     // Draws
 
     /**
-     *  Clear the entire render target, ignoring any clips
+     * Clear the entire or rect of the render target, ignoring any clips.
+     * @param rect  the rect to clear or the whole thing if rect is NULL.
+     * @param color the color to clear to.
      */
-    void clear(GrColor color);
+    void clear(const GrIRect* rect, GrColor color);
 
     /**
      *  Draw everywhere (respecting the clip) with the paint.
diff --git a/gpu/include/GrDrawTarget.h b/gpu/include/GrDrawTarget.h
index cb36d3c91a..c971e717b7 100644
--- a/gpu/include/GrDrawTarget.h
+++ b/gpu/include/GrDrawTarget.h
@@ -731,10 +731,11 @@ public:
     }
 
     /**
-     * Clear the entire render target. Ignores the clip an all other draw state
-     * (blend mode, stages, etc).
+     * Clear the render target. Ignores the clip and all other draw state
+     * (blend mode, stages, etc). Clears the whole thing if rect is NULL,
+     * otherwise just the rect.
      */
-    virtual void clear(GrColor color) = 0;
+    virtual void clear(const GrIRect* rect, GrColor color) = 0;
 
     ///////////////////////////////////////////////////////////////////////////
 
diff --git a/gpu/include/GrGpu.h b/gpu/include/GrGpu.h
index 19f3746616..590712bd48 100644
--- a/gpu/include/GrGpu.h
+++ b/gpu/include/GrGpu.h
@@ -263,7 +263,7 @@ public:
     virtual void drawNonIndexed(GrPrimitiveType type,
                                 int startVertex,
                                 int vertexCount);
-    virtual void clear(GrColor color);
+    virtual void clear(const GrIRect* rect, GrColor color);
 
     /**
      * Installs a path renderer that will be used to draw paths that are
@@ -444,8 +444,9 @@ protected:
     virtual GrIndexBuffer* onCreateIndexBuffer(uint32_t size,
                                                bool dynamic) = 0;
 
-    // overridden by API-specific derivated class to perform the clear.
-    virtual void onClear(GrColor color) = 0;
+    // overridden by API-specific derivated class to perform the clear and 
+    // clearRect. NULL rect means clear whole target.
+    virtual void onClear(const GrIRect* rect, GrColor color) = 0;
 
     // overridden by API-specific derived class to perform the draw call.
     virtual void onDrawIndexed(GrPrimitiveType type,
diff --git a/gpu/include/GrInOrderDrawBuffer.h b/gpu/include/GrInOrderDrawBuffer.h
index 03a2f2d1ee..b26cd7294e 100644
--- a/gpu/include/GrInOrderDrawBuffer.h
+++ b/gpu/include/GrInOrderDrawBuffer.h
@@ -100,7 +100,7 @@ public:
                                int* vertexCount,
                                int* indexCount) const;
 
-    virtual void clear(GrColor color);
+    virtual void clear(const GrIRect* rect, GrColor color);
 
 private:
 
@@ -119,6 +119,7 @@ private:
 
     struct Clear {
         int fBeforeDrawIdx;
+        GrIRect fRect;
         GrColor fColor;
     };
 
diff --git a/gpu/include/GrRect.h b/gpu/include/GrRect.h
index a9ff6ec14d..b85574ab14 100644
--- a/gpu/include/GrRect.h
+++ b/gpu/include/GrRect.h
@@ -76,19 +76,22 @@ struct GrIRect {
 
     /**
      * Sets this rect to the intersection with a clip rect. If there is no
-     * intersection then this rect will be made empty.
+     * intersection then this rect will be made empty and the function will
+     * return false.
      */
-    void intersectWith(const GrIRect& clipRect) {
+    bool intersectWith(const GrIRect& clipRect) {
         if (fRight < clipRect.fLeft ||
             fLeft > clipRect.fRight ||
             fBottom < clipRect.fTop ||
             fTop > clipRect.fBottom) {
             this->setEmpty();
+            return false;
         } else {
             fLeft = GrMax(fLeft, clipRect.fLeft);
             fRight = GrMin(fRight, clipRect.fRight);
             fTop = GrMax(fTop, clipRect.fTop);
             fBottom = GrMin(fBottom, clipRect.fBottom);
+            return true;
         }
     }