1 /*
2  * Copyright 2013 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SkImageDiffer_DEFINED
9 #define SkImageDiffer_DEFINED
10 
11 #include "SkBitmap.h"
12 
13 /**
14  * Encapsulates an image difference metric algorithm that can be potentially run asynchronously.
15  */
16 class SkImageDiffer {
17 public:
18     SkImageDiffer();
19     virtual ~SkImageDiffer();
20 
21     static const double RESULT_CORRECT;
22     static const double RESULT_INCORRECT;
23 
24     struct Result {
25         double result;
26         int poiCount;
27         // TODO(djsollen): Figure out a way that the differ can report which of the
28         // optional fields it has filled in.  See http://skbug.com/2712 ('allow
29         // skpdiff to report different sets of result fields for different comparison algorithms')
30         SkBitmap poiAlphaMask; // optional
31         SkBitmap rgbDiffBitmap; // optional
32         SkBitmap whiteDiffBitmap; // optional
33         int maxRedDiff; // optional
34         int maxGreenDiff; // optional
35         int maxBlueDiff; // optional
36         double timeElapsed; // optional
37     };
38 
39     // A bitfield indicating which bitmap types we want a differ to create.
40     //
41     // TODO(epoger): Remove whiteDiffBitmap, because alphaMask can provide
42     // the same functionality and more.
43     // It will be a little bit tricky, because the rebaseline_server client
44     // and server side code will both need to change to use the alphaMask.
45     struct BitmapsToCreate {
46         bool alphaMask;
47         bool rgbDiff;
48         bool whiteDiff;
49     };
50 
51     /**
52      * Gets a unique and descriptive name of this differ
53      * @return A statically allocated null terminated string that is the name of this differ
54      */
55     virtual const char* getName() const = 0;
56 
57     /**
58      * Gets if this differ needs to be initialized with and OpenCL device and context.
59      */
requiresOpenCL()60     virtual bool requiresOpenCL() const { return false; }
61 
62     /**
63      * diff on a pair of bitmaps.
64      * @param  baseline    The correct bitmap
65      * @param  test        The bitmap whose difference is being tested
66      * @param  bitmapsToCreate  Which bitmaps the differ should attempt to create
67      * @return             true on success, and false in the case of failure
68      */
69     virtual bool diff(SkBitmap* baseline, SkBitmap* test, const BitmapsToCreate& bitmapsToCreate,
70                       Result* result) const = 0;
71 };
72 
73 #endif
74