1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkPictureStateTree.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,148 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2012 Google Inc.
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +#ifndef SkPictureStateTree_DEFINED
1.13 +#define SkPictureStateTree_DEFINED
1.14 +
1.15 +#include "SkTDArray.h"
1.16 +#include "SkChunkAlloc.h"
1.17 +#include "SkDeque.h"
1.18 +#include "SkMatrix.h"
1.19 +#include "SkRefCnt.h"
1.20 +
1.21 +class SkCanvas;
1.22 +
1.23 +/**
1.24 + * Provides an interface that, given a sequence of draws into an SkPicture with corresponding
1.25 + * offsets, allows for playback of an arbitrary subset of the draws (note that Z-order is only
1.26 + * guaranteed if the draws are explicitly sorted).
1.27 + */
1.28 +class SkPictureStateTree : public SkRefCnt {
1.29 +private:
1.30 + struct Node;
1.31 +public:
1.32 + SK_DECLARE_INST_COUNT(SkPictureStateTree)
1.33 +
1.34 + /**
1.35 + * A draw call, stores offset into command buffer, a pointer to the matrix, and a pointer to
1.36 + * the node in the tree that corresponds to its clip/layer state
1.37 + */
1.38 + struct Draw {
1.39 + SkMatrix* fMatrix;
1.40 + Node* fNode;
1.41 + uint32_t fOffset;
1.42 + bool operator<(const Draw& other) const { return fOffset < other.fOffset; }
1.43 + };
1.44 +
1.45 + class Iterator;
1.46 +
1.47 + SkPictureStateTree();
1.48 + ~SkPictureStateTree();
1.49 +
1.50 + /**
1.51 + * Creates and returns a struct representing a draw at the given offset.
1.52 + */
1.53 + Draw* appendDraw(size_t offset);
1.54 +
1.55 + /**
1.56 + * Given a list of draws, and a canvas, returns an iterator that produces the correct sequence
1.57 + * of offsets into the command buffer to carry out those calls with correct matrix/clip state.
1.58 + * This handles saves/restores, and does all necessary matrix setup.
1.59 + */
1.60 + Iterator getIterator(const SkTDArray<void*>& draws, SkCanvas* canvas);
1.61 +
1.62 + void appendSave();
1.63 + void appendSaveLayer(size_t offset);
1.64 + void appendRestore();
1.65 + void appendTransform(const SkMatrix& trans);
1.66 + void appendClip(size_t offset);
1.67 +
1.68 + /**
1.69 + * Call this immediately after an appendRestore call that is associated
1.70 + * a save or saveLayer that was removed from the command stream
1.71 + * due to a command pattern optimization in SkPicture.
1.72 + */
1.73 + void saveCollapsed();
1.74 +
1.75 + /**
1.76 + * Playback helper
1.77 + */
1.78 + class Iterator {
1.79 + public:
1.80 + /** Returns the next offset into the picture stream, or kDrawComplete if complete. */
1.81 + uint32_t draw();
1.82 + static const uint32_t kDrawComplete = SK_MaxU32;
1.83 + Iterator() : fPlaybackMatrix(), fValid(false) { }
1.84 + bool isValid() const { return fValid; }
1.85 + private:
1.86 + Iterator(const SkTDArray<void*>& draws, SkCanvas* canvas, Node* root);
1.87 + // The draws this iterator is associated with
1.88 + const SkTDArray<void*>* fDraws;
1.89 +
1.90 + // canvas this is playing into (so we can insert saves/restores as necessary)
1.91 + SkCanvas* fCanvas;
1.92 +
1.93 + // current state node
1.94 + Node* fCurrentNode;
1.95 +
1.96 + // List of nodes whose state we need to apply to reach TargetNode
1.97 + SkTDArray<Node*> fNodes;
1.98 +
1.99 + // The matrix of the canvas we're playing back into
1.100 + const SkMatrix fPlaybackMatrix;
1.101 +
1.102 + // Cache of current matrix, so we can avoid redundantly setting it
1.103 + SkMatrix* fCurrentMatrix;
1.104 +
1.105 + // current position in the array of draws
1.106 + int fPlaybackIndex;
1.107 + // Whether or not we need to do a save next iteration
1.108 + bool fSave;
1.109 +
1.110 + // Whether or not this is a valid iterator (the default public constructor sets this false)
1.111 + bool fValid;
1.112 +
1.113 + friend class SkPictureStateTree;
1.114 + };
1.115 +
1.116 +private:
1.117 +
1.118 + void appendNode(size_t offset);
1.119 +
1.120 + SkChunkAlloc fAlloc;
1.121 + // Needed by saveCollapsed() because nodes do not currently store
1.122 + // references to their children. If they did, we could just retrieve the
1.123 + // last added child.
1.124 + Node* fLastRestoredNode;
1.125 +
1.126 + // The currently active state
1.127 + Draw fCurrentState;
1.128 + // A stack of states for tracking save/restores
1.129 + SkDeque fStateStack;
1.130 +
1.131 + // Represents a notable piece of state that requires an offset into the command buffer,
1.132 + // corresponding to a clip/saveLayer/etc call, to apply.
1.133 + struct Node {
1.134 + Node* fParent;
1.135 + uint32_t fOffset;
1.136 + uint16_t fLevel;
1.137 + uint16_t fFlags;
1.138 + SkMatrix* fMatrix;
1.139 + enum Flags {
1.140 + kSave_Flag = 0x1,
1.141 + kSaveLayer_Flag = 0x2
1.142 + };
1.143 + };
1.144 +
1.145 + Node fRoot;
1.146 + SkMatrix fRootMatrix;
1.147 +
1.148 + typedef SkRefCnt INHERITED;
1.149 +};
1.150 +
1.151 +#endif
