root/modules/videoio/src/cap_winrt_bridge.cpp

DEFINITIONS

1. requestForUIthreadAsync
2. getInstance
3. swapInputBuffers
4. swapOutputBuffers
5. allocateOutputBuffers
6. allocateBuffers
7. openCamera
8. updateFrameContainer
9. imshow
10. getDeviceIndex
11. setDeviceIndex
12. getWidth
13. getHeight
14. setWidth
15. setHeight

// videoio to XAML bridge for OpenCV

// Copyright (c) Microsoft Open Technologies, Inc.
// All rights reserved.
//
// (3 - clause BSD License)
//
// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
// the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
// following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
// following disclaimer in the documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
// promote products derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

#include "opencv2\videoio\cap_winrt.hpp"
#include "cap_winrt_capture.hpp"
#include "cap_winrt_bridge.hpp"
#include "cap_winrt_video.hpp"

using namespace Windows::Foundation;
using namespace Windows::Media::Capture;
using namespace Windows::Media::MediaProperties;
using namespace Windows::Devices::Enumeration;

using namespace Windows::UI::Xaml::Media::Imaging;
using namespace Microsoft::WRL;

using namespace Platform;
using namespace ::Concurrency;

using namespace ::std;

/***************************** VideoioBridge class ******************************/

// non-blocking
void VideoioBridge::requestForUIthreadAsync(int action)
{
    reporter.report(action);
}

VideoioBridge& VideoioBridge::getInstance()
{
    static VideoioBridge instance;
    return instance;
}

void VideoioBridge::swapInputBuffers()
{
    // TODO: already locked, check validity
    // lock_guard<mutex> lock(inputBufferMutex);
    swap(backInputPtr, frontInputPtr);
    //if (currentFrame != frameCounter)
    //{
    //    currentFrame = frameCounter;
    //    swap(backInputPtr, frontInputPtr);
    //}
}

void VideoioBridge::swapOutputBuffers()
{
    lock_guard<mutex> lock(outputBufferMutex);
    swap(frontOutputBuffer, backOutputBuffer);
}

void VideoioBridge::allocateOutputBuffers()
{
    frontOutputBuffer = ref new WriteableBitmap(width, height);
    backOutputBuffer = ref new WriteableBitmap(width, height);
}

// performed on UI thread
void VideoioBridge::allocateBuffers(int width, int height)
{
    // allocate input Mats (bgra8 = CV_8UC4, RGB24 = CV_8UC3)
    frontInputMat.create(height, width, CV_8UC3);
    backInputMat.create(height, width, CV_8UC3);

    frontInputPtr = frontInputMat.ptr(0);
    backInputPtr = backInputMat.ptr(0);

    allocateOutputBuffers();
}

// performed on UI thread
bool VideoioBridge::openCamera()
{
    // buffers must alloc'd on UI thread
    allocateBuffers(width, height);

    // nb. video capture device init must be done on UI thread;
    if (!Video::getInstance().isStarted())
    {
        Video::getInstance().initGrabber(deviceIndex, width, height);
        return true;
    }

    return false;
}

// nb on UI thread
void VideoioBridge::updateFrameContainer()
{
    // copy output Mat to WBM
    Video::getInstance().CopyOutput();

    // set XAML image element with image WBM
    cvImage->Source = backOutputBuffer;
}

void VideoioBridge::imshow()
{
    swapOutputBuffers();
    requestForUIthreadAsync(cv::UPDATE_IMAGE_ELEMENT);
}

int VideoioBridge::getDeviceIndex()
{
    return deviceIndex;
}

void VideoioBridge::setDeviceIndex(int index)
{
    deviceIndex = index;
}

int VideoioBridge::getWidth()
{
    return width;
}

int VideoioBridge::getHeight()
{
    return height;
}

void VideoioBridge::setWidth(int _width)
{
    width = _width;
}

void VideoioBridge::setHeight(int _height)
{
    height = _height;
}