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      1 // Video support for Windows Runtime
      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 #include <ppl.h>
     28 #include <functional>
     29 #include <concrt.h>
     30 #include <agile.h>
     31 
     32 using namespace Windows::UI::Xaml::Controls;
     33 
     34 namespace cv
     35 {
     36 
     37 //! @addtogroup videoio_winrt
     38 //! @{
     39 
     40 enum {
     41     OPEN_CAMERA = 300,
     42     CLOSE_CAMERA,
     43     UPDATE_IMAGE_ELEMENT,
     44     SHOW_TRACKBAR
     45 };
     46 
     47 /********************************** WinRT API ************************************************/
     48 
     49 template <typename ...Args>
     50 CV_EXPORTS void winrt_startMessageLoop(std::function<void(Args...)>&& callback, Args... args);
     51 
     52 template <typename ...Args>
     53 CV_EXPORTS void winrt_startMessageLoop(void callback(Args...), Args... args);
     54 
     55 /** @brief
     56 @note
     57     Starts (1) frame-grabbing loop and (2) message loop
     58     1. Function passed as an argument must implement common OCV reading frames
     59        pattern (see cv::VideoCapture documentation) AND call cv::winrt_imgshow().
     60     2. Message processing loop required to overcome WinRT container and type
     61        conversion restrictions. OCV provides default implementation
     62        Here is how the class can be used:
     63 @code
     64     void cvMain()
     65     {
     66         Mat frame;
     67         VideoCapture cam;
     68         cam.open(0);
     69 
     70         while (1)
     71         {
     72             cam >> frame;
     73 
     74             // don't reprocess the same frame again
     75             if (!cam.grab()) continue;
     76 
     77             // your processing logic goes here
     78 
     79             // obligatory step to get XAML image component updated
     80             winrt_imshow();
     81         }
     82     }
     83 
     84     MainPage::MainPage()
     85     {
     86         InitializeComponent();
     87 
     88         cv::winrt_setFrameContainer(cvImage);
     89         cv::winrt_startMessageLoop(cvMain);
     90     }
     91 @endcode
     92 */
     93 template
     94 CV_EXPORTS void winrt_startMessageLoop(void callback(void));
     95 
     96 /** @brief
     97 @note
     98     Must be called from WinRT specific callback to handle image grabber state.
     99     Here is how the class can be used:
    100 @code
    101     MainPage::MainPage()
    102     {
    103         // ...
    104         Window::Current->VisibilityChanged += ref new Windows::UI::Xaml::WindowVisibilityChangedEventHandler(this, &Application::MainPage::OnVisibilityChanged);
    105         // ...
    106     }
    107 
    108     void Application::MainPage::OnVisibilityChanged(Platform::Object ^sender,
    109         Windows::UI::Core::VisibilityChangedEventArgs ^e)
    110     {
    111         cv::winrt_onVisibilityChanged(e->Visible);
    112     }
    113 @endcode
    114 */
    115 CV_EXPORTS void winrt_onVisibilityChanged(bool visible);
    116 
    117 /** @brief
    118 @note
    119     Must be called to assign WinRT control holding image you're working with.
    120     Code sample is available for winrt_startMessageLoop().
    121 */
    122 CV_EXPORTS void winrt_setFrameContainer(::Windows::UI::Xaml::Controls::Image^ image);
    123 
    124 /** @brief
    125 @note
    126     Must be called to update attached image source.
    127     Code sample is available for winrt_startMessageLoop().
    128 */
    129 CV_EXPORTS void winrt_imshow();
    130 
    131 //! @} videoio_winrt
    132 
    133 } // cv