michael@0: 
michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef SkPictureStateTree_DEFINED
michael@0: #define SkPictureStateTree_DEFINED
michael@0: 
michael@0: #include "SkTDArray.h"
michael@0: #include "SkChunkAlloc.h"
michael@0: #include "SkDeque.h"
michael@0: #include "SkMatrix.h"
michael@0: #include "SkRefCnt.h"
michael@0: 
michael@0: class SkCanvas;
michael@0: 
michael@0: /**
michael@0:  * Provides an interface that, given a sequence of draws into an SkPicture with corresponding
michael@0:  * offsets, allows for playback of an arbitrary subset of the draws (note that Z-order is only
michael@0:  * guaranteed if the draws are explicitly sorted).
michael@0:  */
michael@0: class SkPictureStateTree : public SkRefCnt {
michael@0: private:
michael@0:     struct Node;
michael@0: public:
michael@0:     SK_DECLARE_INST_COUNT(SkPictureStateTree)
michael@0: 
michael@0:     /**
michael@0:      * A draw call, stores offset into command buffer, a pointer to the matrix, and a pointer to
michael@0:      * the node in the tree that corresponds to its clip/layer state
michael@0:      */
michael@0:     struct Draw {
michael@0:         SkMatrix* fMatrix;
michael@0:         Node* fNode;
michael@0:         uint32_t fOffset;
michael@0:         bool operator<(const Draw& other) const { return fOffset < other.fOffset; }
michael@0:     };
michael@0: 
michael@0:     class Iterator;
michael@0: 
michael@0:     SkPictureStateTree();
michael@0:     ~SkPictureStateTree();
michael@0: 
michael@0:     /**
michael@0:      * Creates and returns a struct representing a draw at the given offset.
michael@0:      */
michael@0:     Draw* appendDraw(size_t offset);
michael@0: 
michael@0:     /**
michael@0:      * Given a list of draws, and a canvas, returns an iterator that produces the correct sequence
michael@0:      * of offsets into the command buffer to carry out those calls with correct matrix/clip state.
michael@0:      * This handles saves/restores, and does all necessary matrix setup.
michael@0:      */
michael@0:     Iterator getIterator(const SkTDArray<void*>& draws, SkCanvas* canvas);
michael@0: 
michael@0:     void appendSave();
michael@0:     void appendSaveLayer(size_t offset);
michael@0:     void appendRestore();
michael@0:     void appendTransform(const SkMatrix& trans);
michael@0:     void appendClip(size_t offset);
michael@0: 
michael@0:     /**
michael@0:      * Call this immediately after an appendRestore call that is associated
michael@0:      * a save or saveLayer that was removed from the command stream
michael@0:      * due to a command pattern optimization in SkPicture.
michael@0:      */
michael@0:     void saveCollapsed();
michael@0: 
michael@0:     /**
michael@0:      * Playback helper
michael@0:      */
michael@0:     class Iterator {
michael@0:     public:
michael@0:         /** Returns the next offset into the picture stream, or kDrawComplete if complete. */
michael@0:         uint32_t draw();
michael@0:         static const uint32_t kDrawComplete = SK_MaxU32;
michael@0:         Iterator() : fPlaybackMatrix(), fValid(false) { }
michael@0:         bool isValid() const { return fValid; }
michael@0:     private:
michael@0:         Iterator(const SkTDArray<void*>& draws, SkCanvas* canvas, Node* root);
michael@0:         // The draws this iterator is associated with
michael@0:         const SkTDArray<void*>* fDraws;
michael@0: 
michael@0:         // canvas this is playing into (so we can insert saves/restores as necessary)
michael@0:         SkCanvas* fCanvas;
michael@0: 
michael@0:         // current state node
michael@0:         Node* fCurrentNode;
michael@0: 
michael@0:         // List of nodes whose state we need to apply to reach TargetNode
michael@0:         SkTDArray<Node*> fNodes;
michael@0: 
michael@0:         // The matrix of the canvas we're playing back into
michael@0:         const SkMatrix fPlaybackMatrix;
michael@0: 
michael@0:         // Cache of current matrix, so we can avoid redundantly setting it
michael@0:         SkMatrix* fCurrentMatrix;
michael@0: 
michael@0:         // current position in the array of draws
michael@0:         int fPlaybackIndex;
michael@0:         // Whether or not we need to do a save next iteration
michael@0:         bool fSave;
michael@0: 
michael@0:         // Whether or not this is a valid iterator (the default public constructor sets this false)
michael@0:         bool fValid;
michael@0: 
michael@0:         friend class SkPictureStateTree;
michael@0:     };
michael@0: 
michael@0: private:
michael@0: 
michael@0:     void appendNode(size_t offset);
michael@0: 
michael@0:     SkChunkAlloc fAlloc;
michael@0:     // Needed by saveCollapsed() because nodes do not currently store
michael@0:     // references to their children.  If they did, we could just retrieve the
michael@0:     // last added child.
michael@0:     Node* fLastRestoredNode;
michael@0: 
michael@0:     // The currently active state
michael@0:     Draw fCurrentState;
michael@0:     // A stack of states for tracking save/restores
michael@0:     SkDeque fStateStack;
michael@0: 
michael@0:     // Represents a notable piece of state that requires an offset into the command buffer,
michael@0:     // corresponding to a clip/saveLayer/etc call, to apply.
michael@0:     struct Node {
michael@0:         Node* fParent;
michael@0:         uint32_t fOffset;
michael@0:         uint16_t fLevel;
michael@0:         uint16_t fFlags;
michael@0:         SkMatrix* fMatrix;
michael@0:         enum Flags {
michael@0:             kSave_Flag      = 0x1,
michael@0:             kSaveLayer_Flag = 0x2
michael@0:         };
michael@0:     };
michael@0: 
michael@0:     Node fRoot;
michael@0:     SkMatrix fRootMatrix;
michael@0: 
michael@0:     typedef SkRefCnt INHERITED;
michael@0: };
michael@0: 
michael@0: #endif