Split SkPictureReplacementPlayback out of SkPicturePlayback

src/core/SkPictureReplacementPlayback.h

Index: src/core/SkPictureReplacementPlayback.h
diff --git a/src/core/SkPictureReplacementPlayback.h b/src/core/SkPictureReplacementPlayback.h
new file mode 100644
index 0000000000000000000000000000000000000000..166a3bfbd350b326925e27380d6573b13a2af393
--- /dev/null
+++ b/src/core/SkPictureReplacementPlayback.h
@@ -0,0 +1,86 @@
+/*
+ * 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 SkPictureReplacementPlayback_DEFINED
+#define SkPictureReplacementPlayback_DEFINED
+
+#include "SkPicturePlayback.h"
+
+// This playback class replaces complete "saveLayer ... restore" runs with a
+// single drawBitmap call.
+class SkPictureReplacementPlayback : public SkPicturePlayback {
+public:
+    // PlaybackReplacements collects op ranges that can be replaced with
+    // a single drawBitmap call (using a precomputed bitmap).
+    class PlaybackReplacements {
+    public:
+        // All the operations between fStart and fStop (inclusive) will be replaced with
+        // a single drawBitmap call using fPos, fBM and fPaint.
+        // fPaint will be NULL if the picture's paint wasn't copyable
+        struct ReplacementInfo {
+            size_t          fStart;
+            size_t          fStop;
+            SkIPoint        fPos;
+            SkBitmap*       fBM;     // fBM is allocated so ReplacementInfo can remain POD
+            const SkPaint*  fPaint;  // Note: this object doesn't own the paint
+
+            SkIRect         fSrcRect;
+        };
+
+        ~PlaybackReplacements() { this->freeAll(); }
+
+        // Add a new replacement range. The replacement ranges should be
+        // sorted in increasing order and non-overlapping (esp. no nested
+        // saveLayers).
+        ReplacementInfo* push();
+
+        // look up a replacement range by its start offset
+        ReplacementInfo* lookupByStart(size_t start);
+
+    private:
+        SkTDArray<ReplacementInfo> fReplacements;
+
+        void freeAll();
+
+#ifdef SK_DEBUG
+        void validate() const;
+#endif
+    };
+
+    // This class doesn't take ownership of either 'replacements' or 'activeOpsList'
+    // The caller must guarantee they exist across any calls to 'draw'.
+    // 'activeOpsList' can be NULL but in that case BBH acceleration will not 
+    // be used ('replacements' can be NULL too but that defeats the purpose
+    // of using this class).
+    SkPictureReplacementPlayback(const SkPicture* picture, 
+                                 PlaybackReplacements* replacements,
+                                 const SkPicture::OperationList* activeOpsList)
+        : INHERITED(picture)
+        , fReplacements(replacements)
+        , fActiveOpsList(activeOpsList) {
+    }
+
+    virtual void draw(SkCanvas* canvas, SkDrawPictureCallback*) SK_OVERRIDE;
+
+private:
+    PlaybackReplacements*           fReplacements;
+    const SkPicture::OperationList* fActiveOpsList;
+
+    // This method checks if the current op pointed at by 'iter' and 'reader'
+    // is within a replacement range. If so, it issues the drawBitmap call,
+    // updates 'iter' and 'reader' to be after the restore operation, and
+    // returns true. If the operation is not in a replacement range (and thus
+    // needs to be drawn normally) false is returned.
+    bool replaceOps(SkPictureStateTree::Iterator* iter,
+                    SkReader32* reader,
+                    SkCanvas* canvas,
+                    const SkMatrix& initialMatrix);
+
+    typedef SkPicturePlayback INHERITED;
+};
+
+#endif