add gpu backend (not hooked up yet)



git-svn-id: http://skia.googlecode.com/svn/trunk@649 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrRectanizer.h b/gpu/include/GrRectanizer.h
new file mode 100644
index 0000000..50bb8fe
--- /dev/null
+++ b/gpu/include/GrRectanizer.h
@@ -0,0 +1,64 @@
+/*
+    Copyright 2010 Google Inc.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ */
+
+
+#ifndef GrRectanizer_DEFINED
+#define GrRectanizer_DEFINED
+
+#include "GrRect.h"
+#include "GrTDArray.h"
+
+class GrRectanizerPurgeListener {
+public:
+    virtual ~GrRectanizerPurgeListener() {}
+
+    virtual void notifyPurgeStrip(void*, int yCoord) = 0;
+};
+
+class GrRectanizer {
+public:
+    GrRectanizer(int width, int height) : fWidth(width), fHeight(height) {
+        GrAssert(width >= 0);
+        GrAssert(height >= 0);
+    }
+
+    virtual ~GrRectanizer() {}
+
+    int width() const { return fWidth; }
+    int height() const { return fHeight; }
+
+    virtual bool addRect(int width, int height, GrIPoint16* loc) = 0;
+    virtual float percentFull() const = 0;
+
+    // return the Y-coordinate of a strip that should be purged, given height
+    // i.e. return the oldest such strip, or some other criteria. Return -1
+    // if there is no candidate
+    virtual int stripToPurge(int height) const = 0;
+    virtual void purgeStripAtY(int yCoord) = 0;
+
+    /**
+     *  Our factory, which returns the subclass du jour
+     */
+    static GrRectanizer* Factory(int width, int height);
+
+private:
+    int fWidth;
+    int fHeight;
+};
+
+#endif
+
+