Add SkPictureRecord subclass that computes bounding boxes.

Review URL: https://codereview.appspot.com/6506082

git-svn-id: http://skia.googlecode.com/svn/trunk@5423 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 76 insertions, 0 deletions

diff --git a/src/core/SkBBoxRecord.h b/src/core/SkBBoxRecord.h
new file mode 100644
index 0000000000..5a90727151
--- /dev/null
+++ b/src/core/SkBBoxRecord.h
@@ -0,0 +1,76 @@
+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBBoxRecord_DEFINED
+#define SkBBoxRecord_DEFINED
+
+#include "SkPictureRecord.h"
+
+/**
+  * This is an abstract SkPictureRecord subclass that intercepts draw calls and computes an 
+  * axis-aligned bounding box for each draw that it sees, subclasses implement handleBBox()
+  * which will be called every time we get a new bounding box.
+  */
+class SkBBoxRecord : public SkPictureRecord {
+public:
+
+    SkBBoxRecord(uint32_t recordFlags) :INHERITED(recordFlags) { }
+    virtual ~SkBBoxRecord() { }
+
+    /**
+     * This is called each time we get a bounding box, it will be axis-aligned,
+     * in device coordinates, and expanded to include stroking, shadows, etc.
+     */
+    virtual void handleBBox(const SkRect& bbox) = 0;
+
+    virtual void drawRect(const SkRect& rect, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPath(const SkPath& path, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPoints(PointMode mode, size_t count, const SkPoint pts[],
+                            const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPaint(const SkPaint& paint) SK_OVERRIDE;
+    virtual void clear(SkColor) SK_OVERRIDE;
+    virtual void drawText(const void* text, size_t byteLength, SkScalar x, SkScalar y, 
+                          const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top,
+                            const SkPaint* paint = NULL) SK_OVERRIDE;
+    virtual void drawBitmapRect(const SkBitmap& bitmap, const SkIRect* src,
+                                const SkRect& dst, const SkPaint* paint) SK_OVERRIDE;
+    virtual void drawBitmapMatrix(const SkBitmap& bitmap, const SkMatrix& mat,
+                                  const SkPaint* paint) SK_OVERRIDE;
+    virtual void drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center,
+                                const SkRect& dst, const SkPaint* paint) SK_OVERRIDE;
+    virtual void drawPosText(const void* text, size_t byteLength,
+                             const SkPoint pos[], const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPosTextH(const void* text, size_t byteLength,
+                              const SkScalar xpos[], SkScalar constY, 
+                              const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawSprite(const SkBitmap& bitmap, int left, int top,
+                            const SkPaint* paint) SK_OVERRIDE;
+    virtual void drawTextOnPath(const void* text, size_t byteLength,
+                                const SkPath& path, const SkMatrix* matrix,
+                                const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawVertices(VertexMode mode, int vertexCount,
+                              const SkPoint vertices[], const SkPoint texs[],
+                              const SkColor colors[], SkXfermode* xfer,
+                              const uint16_t indices[], int indexCount,
+                              const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPicture(SkPicture& picture) SK_OVERRIDE;
+
+private:
+    /** 
+     * Takes a bounding box in current canvas view space, accounts for stroking and effects, and
+     * computes an axis-aligned bounding box in device coordinates, then passes it to handleBBox()
+     * returns false if the draw is completely clipped out, and may safely be ignored.
+     **/
+    bool transformBounds(const SkRect& bounds, const SkPaint* paint);
+
+    typedef SkPictureRecord INHERITED;
+};
+
+#endif
+