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1 // videoio to XAML bridge for OpenCV
2 
3 // Copyright (c) Microsoft Open Technologies, Inc.
4 // All rights reserved.
5 //
6 // (3 - clause BSD License)
7 //
8 // Redistribution and use in source and binary forms, with or without modification, are permitted provided that
9 // the following conditions are met:
10 //
11 // 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
12 // following disclaimer.
13 // 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
14 // following disclaimer in the documentation and/or other materials provided with the distribution.
15 // 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
16 // promote products derived from this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
19 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
20 // PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
21 // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
22 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
24 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 // POSSIBILITY OF SUCH DAMAGE.
26 
27 #pragma once
28 
29 // this header is included in the XAML App, so it cannot include any
30 // OpenCV headers, or a static assert will be raised
31 
32 #include <ppl.h>
33 #include <ppltasks.h>
34 #include <concrt.h>
35 #include <agile.h>
36 #include <opencv2\core.hpp>
37 
38 #include <mutex>
39 #include <memory>
40 #include <atomic>
41 #include <functional>
42 
43 
44 // Class VideoioBridge (singleton) is needed because the interface for
45 // VideoCapture_WinRT in cap_winrt_capture.hpp is fixed by OpenCV.
46 class VideoioBridge
47 {
48 public:
49 
50     static VideoioBridge& getInstance();
51 
52     // call after initialization
setReporter(Concurrency::progress_reporter<int> pr)53     void    setReporter(Concurrency::progress_reporter<int> pr) { reporter = pr; }
54 
55     // to be called from cvMain via cap_winrt on bg thread - non-blocking (async)
56     void    requestForUIthreadAsync(int action);
57 
58     // TODO: modify in window.cpp: void cv::imshow( const String& winname, InputArray _img )
59     void    imshow(/*cv::InputArray matToShow*/);   // shows Mat in the cvImage element
60     void    swapInputBuffers();
61     void    allocateOutputBuffers();
62     void    swapOutputBuffers();
63     void    updateFrameContainer();
64     bool    openCamera();
65     void    allocateBuffers(int width, int height);
66 
67     int     getDeviceIndex();
68     void    setDeviceIndex(int index);
69     int     getWidth();
70     void    setWidth(int width);
71     int     getHeight();
72     void    setHeight(int height);
73 
74     std::atomic<bool>           bIsFrameNew;
75     std::mutex                  inputBufferMutex;   // input is double buffered
76     unsigned char *             frontInputPtr;      // OpenCV reads this
77     unsigned char *             backInputPtr;       // Video grabber writes this
78     std::atomic<unsigned long>  frameCounter;
79     unsigned long               currentFrame;
80 
81     std::mutex                  outputBufferMutex;  // output is double buffered
82     Windows::UI::Xaml::Media::Imaging::WriteableBitmap^ frontOutputBuffer;  // OpenCV write this
83     Windows::UI::Xaml::Media::Imaging::WriteableBitmap^ backOutputBuffer;   // XAML reads this
84     Windows::UI::Xaml::Controls::Image ^cvImage;
85 
86 private:
87 
VideoioBridge()88     VideoioBridge() {
89         deviceIndex = 0;
90         width = 640;
91         height = 480;
92         deviceReady = false;
93         bIsFrameNew = false;
94         currentFrame = 0;
95         frameCounter = 0;
96     };
97 
98     // singleton
99     VideoioBridge(VideoioBridge const &);
100     void operator=(const VideoioBridge &);
101 
102     std::atomic<bool>   deviceReady;
103     Concurrency::progress_reporter<int> reporter;
104 
105     // Mats are wrapped with singleton class, we do not support more than one
106     // capture device simultaneously with the design at this time
107     //
108     // nb. inputBufferMutex was not able to guarantee that OpenCV Mats were
109     // ready to accept data in the UI thread (memory access exceptions were thrown
110     // even though buffer address was good).
111     // Therefore allocation of Mats is also done on the UI thread before the video
112     // device is initialized.
113     cv::Mat frontInputMat;
114     cv::Mat backInputMat;
115 
116     int deviceIndex, width, height;
117 };