rename SkCanvasDrawable to SkDrawable, and make public

BUG=skia:
NOTRY=True
... winbuilder flake

Review URL: https://codereview.chromium.org/903993002

3 files changed, 89 insertions, 5 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 53ca92ee95..0ec167e116 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -21,8 +21,8 @@
 
 class SkBaseDevice;
 class SkCanvasClipVisitor;
-class SkCanvasDrawable;
 class SkDraw;
+class SkDrawable;
 class SkDrawFilter;
 class SkImage;
 class SkMetaData;
@@ -1018,7 +1018,15 @@ public:
     void drawPatch(const SkPoint cubics[12], const SkColor colors[4],
                    const SkPoint texCoords[4], SkXfermode* xmode, const SkPaint& paint);
 
-    void EXPERIMENTAL_drawDrawable(SkCanvasDrawable*);
+    /**
+     *  Draw the contents of this drawable into the canvas. If the canvas is async
+     *  (e.g. it is recording into a picture) then the drawable will be referenced instead,
+     *  to have its draw() method called when the picture is finalized.
+     *
+     *  If the intent is to force the contents of the drawable into this canvas immediately,
+     *  then drawable->draw(canvas) may be called.
+     */
+    void drawDrawable(SkDrawable* drawable);
 
     /** Add comments. beginCommentGroup/endCommentGroup open/close a new group.
         Each comment added via addComment is notionally attached to its
@@ -1188,7 +1196,7 @@ protected:
     virtual void onDrawPatch(const SkPoint cubics[12], const SkColor colors[4],
                            const SkPoint texCoords[4], SkXfermode* xmode, const SkPaint& paint);
 
-    virtual void onDrawDrawable(SkCanvasDrawable*);
+    virtual void onDrawDrawable(SkDrawable*);
 
     virtual void onDrawPaint(const SkPaint&);
     virtual void onDrawRect(const SkRect&, const SkPaint&);
diff --git a/include/core/SkDrawable.h b/include/core/SkDrawable.h
new file mode 100644
index 0000000000..15bb0bbe0f
--- /dev/null
+++ b/include/core/SkDrawable.h
@@ -0,0 +1,76 @@
+/*
+ * 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 SkDrawable_DEFINED
+#define SkDrawable_DEFINED
+
+#include "SkRefCnt.h"
+
+class SkCanvas;
+class SkPicture;
+struct SkRect;
+
+/**
+ *  Base-class for objects that draw into SkCanvas.
+ *
+ *  The object has a generation ID, which is guaranteed to be unique across all drawables. To
+ *  allow for clients of the drawable that may want to cache the results, the drawable must
+ *  change its generation ID whenever its internal state changes such that it will draw differently.
+ */
+class SkDrawable : public SkRefCnt {
+public:
+    SkDrawable();
+
+    /**
+     *  Draws into the specified content. The drawing sequence will be balanced upon return
+     *  (i.e. the saveLevel() on the canvas will match what it was when draw() was called,
+     *  and the current matrix and clip settings will not be changed.
+     */
+    void draw(SkCanvas*);
+
+    SkPicture* newPictureSnapshot();
+
+    /**
+     *  Return a unique value for this instance. If two calls to this return the same value,
+     *  it is presumed that calling the draw() method will render the same thing as well.
+     *
+     *  Subclasses that change their state should call notifyDrawingChanged() to ensure that
+     *  a new value will be returned the next time it is called.
+     */
+    uint32_t getGenerationID();
+
+    /**
+     *  Return the (conservative) bounds of what the drawable will draw. If the drawable can
+     *  change what it draws (e.g. animation or in response to some external change), then this
+     *  must return a bounds that is always valid for all possible states.
+     */
+    SkRect getBounds();
+
+    /**
+     *  Calling this invalidates the previous generation ID, and causes a new one to be computed
+     *  the next time getGenerationID() is called. Typically this is called by the object itself,
+     *  in response to its internal state changing.
+     */
+    void notifyDrawingChanged();
+
+protected:
+    virtual SkRect onGetBounds() = 0;
+    virtual void onDraw(SkCanvas*) = 0;
+    
+    /**
+     *  Default implementation calls onDraw() with a canvas that records into a picture. Subclasses
+     *  may override if they have a more efficient way to return a picture for the current state
+     *  of their drawable. Note: this picture must draw the same as what would be drawn from
+     *  onDraw().
+     */
+    virtual SkPicture* onNewPictureSnapshot();
+
+private:
+    int32_t fGenerationID;
+};
+
+#endif
diff --git a/include/core/SkPictureRecorder.h b/include/core/SkPictureRecorder.h
index 14443b23d8..b25e26b26a 100644
--- a/include/core/SkPictureRecorder.h
+++ b/include/core/SkPictureRecorder.h
@@ -19,7 +19,7 @@ namespace android {
 #endif
 
 class SkCanvas;
-class SkCanvasDrawable;
+class SkDrawable;
 class SkPictureRecord;
 class SkRecord;
 class SkRecorder;
@@ -79,7 +79,7 @@ public:
      *  and therefore this drawable will reflect the current state of those nested drawables anytime
      *  it is drawn or a new picture is snapped from it (by calling drawable->newPictureSnapshot()).
      */
-    SkCanvasDrawable* EXPERIMENTAL_endRecordingAsDrawable();
+    SkDrawable* endRecordingAsDrawable();
 
     // Legacy API -- use endRecordingAsPicture instead.
     SkPicture* endRecording() { return this->endRecordingAsPicture(); }