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1 /*
2  * Copyright (C) 2007 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef SkPicture_DEFINED
18 #define SkPicture_DEFINED
19 
20 #include "SkRefCnt.h"
21 
22 class SkCanvas;
23 class SkPicturePlayback;
24 class SkPictureRecord;
25 class SkStream;
26 class SkWStream;
27 
28 /** \class SkPicture
29 
30     The SkPicture class records the drawing commands made to a canvas, to
31     be played back at a later time.
32 */
33 class SkPicture : public SkRefCnt {
34 public:
35     /** The constructor prepares the picture to record.
36         @param width the width of the virtual device the picture records.
37         @param height the height of the virtual device the picture records.
38     */
39     SkPicture();
40     /** Make a copy of the contents of src. If src records more drawing after
41         this call, those elements will not appear in this picture.
42     */
43     SkPicture(const SkPicture& src);
44     explicit SkPicture(SkStream*);
45     virtual ~SkPicture();
46 
47     /**
48      *  Swap the contents of the two pictures. Guaranteed to succeed.
49      */
50     void swap(SkPicture& other);
51 
52     enum RecordingFlags {
53         /*  This flag specifies that when clipPath() is called, the path will
54             be faithfully recorded, but the recording canvas' current clip will
55             only see the path's bounds. This speeds up the recording process
56             without compromising the fidelity of the playback. The only side-
57             effect for recording is that calling getTotalClip() or related
58             clip-query calls will reflect the path's bounds, not the actual
59             path.
60          */
61         kUsePathBoundsForClip_RecordingFlag = 0x01
62     };
63 
64     /** Returns the canvas that records the drawing commands.
65         @param width the base width for the picture, as if the recording
66                      canvas' bitmap had this width.
67         @param height the base width for the picture, as if the recording
68                      canvas' bitmap had this height.
69         @param recordFlags optional flags that control recording.
70         @return the picture canvas.
71     */
72     SkCanvas* beginRecording(int width, int height, uint32_t recordFlags = 0);
73 
74     /** Returns the recording canvas if one is active, or NULL if recording is
75         not active. This does not alter the refcnt on the canvas (if present).
76     */
77     SkCanvas* getRecordingCanvas() const;
78     /** Signal that the caller is done recording. This invalidates the canvas
79         returned by beginRecording/getRecordingCanvas, and prepares the picture
80         for drawing. Note: this happens implicitly the first time the picture
81         is drawn.
82     */
83     void endRecording();
84 
85     /** Replays the drawing commands on the specified canvas. This internally
86         calls endRecording() if that has not already been called.
87         @param surface the canvas receiving the drawing commands.
88     */
89     void draw(SkCanvas* surface);
90 
91     /** Return the width of the picture's recording canvas. This
92         value reflects what was passed to setSize(), and does not necessarily
93         reflect the bounds of what has been recorded into the picture.
94         @return the width of the picture's recording canvas
95     */
width()96     int width() const { return fWidth; }
97 
98     /** Return the height of the picture's recording canvas. This
99         value reflects what was passed to setSize(), and does not necessarily
100         reflect the bounds of what has been recorded into the picture.
101         @return the height of the picture's recording canvas
102     */
height()103     int height() const { return fHeight; }
104 
105     void serialize(SkWStream*) const;
106 
107     /** Signals that the caller is prematurely done replaying the drawing
108         commands. This can be called from a canvas virtual while the picture
109         is drawing. Has no effect if the picture is not drawing.
110     */
111     void abortPlayback();
112 
113 private:
114     int fWidth, fHeight;
115     SkPictureRecord* fRecord;
116     SkPicturePlayback* fPlayback;
117 
118     friend class SkFlatPicture;
119     friend class SkPicturePlayback;
120 };
121 
122 class SkAutoPictureRecord : SkNoncopyable {
123 public:
124     SkAutoPictureRecord(SkPicture* pict, int width, int height,
125                         uint32_t recordingFlags = 0) {
126         fPicture = pict;
127         fCanvas = pict->beginRecording(width, height, recordingFlags);
128     }
~SkAutoPictureRecord()129     ~SkAutoPictureRecord() {
130         fPicture->endRecording();
131     }
132 
133     /** Return the canvas to draw into for recording into the picture.
134     */
getRecordingCanvas()135     SkCanvas* getRecordingCanvas() const { return fCanvas; }
136 
137 private:
138     SkPicture*  fPicture;
139     SkCanvas*   fCanvas;
140 };
141 
142 
143 #endif
144