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Refactored internal helpers. Simplified structure. Updated comments. …
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…Updates opencv#41

Signed-off-by: Maxim Kostin <[email protected]>
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@mkostin
mkostin committed May 22, 2015
1 parent 3136010 commit 4418ee6
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Showing 9 changed files with 134 additions and 134 deletions.
9 changes: 6 additions & 3 deletions modules/videoio/include/opencv2/videoio/cap_winrt.hpp
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Expand Up @@ -54,9 +54,12 @@ CV_EXPORTS void winrt_startMessageLoop(void callback(Args...), Args... args);

/** @brief
@note
Sets the reporter method for the HighguiAssist singleton. Starts the main OpenCV as
an async thread in WinRT. See VideoCapture for the example of callback implementation.
Here is how the class can be used:
Starts (1) frame-grabbing loop and (2) message loop
1. Function passed as an argument must implement common OCV reading frames
pattern (see cv::VideoCapture documentation) AND call cv::winrt_imgshow().
2. Message processing loop required to overcome WinRT container and type
conversion restrictions. OCV provides default implementation
Here is how the class can be used:
@code
void cvMain()
{
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2 changes: 1 addition & 1 deletion modules/videoio/src/cap.cpp
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Expand Up @@ -697,7 +697,7 @@ VideoCapture& VideoCapture::operator >> (Mat& image)
bridge.bIsFrameNew = false;

// needed here because setting Mat 'image' is not allowed by OutputArray in read()
Mat m(bridge.height, bridge.width, CV_8UC3, p);
Mat m(bridge.getHeight(), bridge.getWidth(), CV_8UC3, p);
image = m;
}
}
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2 changes: 0 additions & 2 deletions modules/videoio/src/cap_winrt/MediaStreamSink.cpp
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Expand Up @@ -227,7 +227,6 @@ HRESULT MediaStreamSink::IsMediaTypeSupported(__in IMFMediaType *mediaType, __de
HRESULT hr = ExceptionBoundary([this, mediaType, closestMediaType, &supported]()
{
auto lock = _lock.LockExclusive();
HRESULT hr = S_OK;

if (closestMediaType != nullptr)
{
Expand Down Expand Up @@ -281,7 +280,6 @@ HRESULT MediaStreamSink::SetCurrentMediaType(__in IMFMediaType *mediaType)
return ExceptionBoundary([this, mediaType]()
{
auto lock = _lock.LockExclusive();
HRESULT hr = S_OK;

CHKNULL(mediaType);

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75 changes: 72 additions & 3 deletions modules/videoio/src/cap_winrt_bridge.cpp
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Expand Up @@ -45,7 +45,7 @@ using namespace ::std;
/***************************** VideoioBridge class ******************************/

// non-blocking
void VideoioBridge::requestForUIthreadAsync(int action, int widthp, int heightp)
void VideoioBridge::requestForUIthreadAsync(int action)
{
reporter.report(action);
}
Expand Down Expand Up @@ -80,10 +80,79 @@ void VideoioBridge::allocateOutputBuffers()
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()
{
VideoioBridge::getInstance().swapOutputBuffers();
VideoioBridge::getInstance().requestForUIthreadAsync(cv::UPDATE_IMAGE_ELEMENT);
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;
}

// end
27 changes: 24 additions & 3 deletions modules/videoio/src/cap_winrt_bridge.hpp
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Expand Up @@ -50,19 +50,27 @@ class VideoioBridge
static VideoioBridge& getInstance();

// call after initialization
void setReporter(Concurrency::progress_reporter<int> pr) { reporter = pr; }
void setReporter(Concurrency::progress_reporter<int> pr) { reporter = pr; }

// to be called from cvMain via cap_winrt on bg thread - non-blocking (async)
void requestForUIthreadAsync( int action, int width=0, int height=0 );
void requestForUIthreadAsync(int action);

// TODO: modify in window.cpp: void cv::imshow( const String& winname, InputArray _img )
void imshow(/*cv::InputArray matToShow*/); // shows Mat in the cvImage element
void swapInputBuffers();
void allocateOutputBuffers();
void swapOutputBuffers();
void updateFrameContainer();
bool openCamera();
void allocateBuffers(int width, int height);

int getDeviceIndex();
void setDeviceIndex(int index);
int getWidth();
void setWidth(int width);
int getHeight();
void setHeight(int height);

int deviceIndex, width, height;
std::atomic<bool> bIsFrameNew;
std::mutex inputBufferMutex; // input is double buffered
unsigned char * frontInputPtr; // OpenCV reads this
Expand Down Expand Up @@ -93,4 +101,17 @@ class VideoioBridge

std::atomic<bool> deviceReady;
Concurrency::progress_reporter<int> reporter;

// Mats are wrapped with singleton class, we do not support more than one
// capture device simultaneously with the design at this time
//
// nb. inputBufferMutex was not able to guarantee that OpenCV Mats were
// ready to accept data in the UI thread (memory access exceptions were thrown
// even though buffer address was good).
// Therefore allocation of Mats is also done on the UI thread before the video
// device is initialized.
cv::Mat frontInputMat;
cv::Mat backInputMat;

int deviceIndex, width, height;
};
117 changes: 19 additions & 98 deletions modules/videoio/src/cap_winrt_capture.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,23 +43,9 @@ using namespace Microsoft::WRL;

using namespace ::std;


// nb. VideoCapture_WinRT is not a singleton, so the Mats are made file statics
// we do not support more than one capture device simultaneously with the
// design at this time

// nb. inputBufferMutex was not able to guarantee that OpenCV Mats were
// ready to accept data in the UI thread (memory access exceptions were thrown
// even though buffer address was good).
// Therefore allocation of Mats is also done on the UI thread before the video
// device is initialized.

static cv::Mat frontInputMat;
static cv::Mat backInputMat;

namespace cv {

/***************************** exported control functions ******************************/
/******************************* exported API functions **************************************/

template <typename ...Args>
void winrt_startMessageLoop(std::function<void(Args...)>&& callback, Args... args)
Expand All @@ -80,13 +66,13 @@ namespace cv {
switch (action)
{
case OPEN_CAMERA:
winrt_openCamera();
VideoioBridge::getInstance().openCamera();
break;
case CLOSE_CAMERA:
winrt_closeGrabber();
Video::getInstance().closeGrabber();
break;
case UPDATE_IMAGE_ELEMENT:
winrt_updateFrameContainer();
VideoioBridge::getInstance().updateFrameContainer();
break;
}
});
Expand All @@ -98,7 +84,8 @@ namespace cv {
winrt_startMessageLoop(std::function<void(Args...)>(callback), args...);
}

void winrt_onVisibilityChanged(bool visible) {
void winrt_onVisibilityChanged(bool visible)
{
if (visible)
{
VideoioBridge& bridge = VideoioBridge::getInstance();
Expand All @@ -108,99 +95,34 @@ namespace cv {
{
if (Video::getInstance().isStarted()) return;

int device = bridge.deviceIndex;
int width = bridge.width;
int height = bridge.height;
int device = bridge.getDeviceIndex();
int width = bridge.getWidth();
int height = bridge.getHeight();

winrt_initGrabber(device, width, height);
Video::getInstance().initGrabber(device, width, height);
}
} else
{
//grabberStarted = false;
winrt_closeGrabber();
Video::getInstance().closeGrabber();
}
}

void winrt_imshow() {
VideoioBridge::getInstance().imshow();
}

void winrt_setFrameContainer(::Windows::UI::Xaml::Controls::Image^ image) {
VideoioBridge::getInstance().cvImage = image;
}


/********************************* Internal helpers ************************************/

void winrt_updateFrameContainer()
void winrt_imshow()
{
// copy output Mat to WBM
winrt_copyOutput();

// set XAML image element with image WBM
VideoioBridge::getInstance().cvImage->Source = VideoioBridge::getInstance().backOutputBuffer;
}

// performed on UI thread
bool winrt_openCamera()
{
VideoioBridge& bridge = VideoioBridge::getInstance();

int device = bridge.deviceIndex;
int width = bridge.width;
int height = bridge.height;

// buffers must alloc'd on UI thread
winrt_allocateBuffers(width, height);

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

return false;
VideoioBridge::getInstance().imshow();
}

// performed on UI thread
void winrt_allocateBuffers(int width, int height)
void winrt_setFrameContainer(::Windows::UI::Xaml::Controls::Image^ image)
{
VideoioBridge& bridge = VideoioBridge::getInstance();

// allocate input Mats (bgra8 = CV_8UC4, RGB24 = CV_8UC3)
frontInputMat.create(height, width, CV_8UC3);
backInputMat.create(height, width, CV_8UC3);

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

bridge.allocateOutputBuffers();
}

// non-blocking
bool winrt_initGrabber(int device, int w, int h) {
// nb. Video class is not exported outside of this DLL
// due to complexities in the CaptureFrameGrabber ref class
// as written in the header not mixing well with pure C++ classes
return Video::getInstance().initGrabber(device, w, h);
}

void winrt_closeGrabber() {
Video::getInstance().closeGrabber();
}

// nb on UI thread
void winrt_copyOutput() {
Video::getInstance().CopyOutput();
VideoioBridge::getInstance().cvImage = image;
}


/********************************* VideoCapture_WinRT class ****************************/

VideoCapture_WinRT::VideoCapture_WinRT(int device) : started(false)
{
VideoioBridge::getInstance().deviceIndex = device;
VideoioBridge::getInstance().setDeviceIndex(device);
}

bool VideoCapture_WinRT::isOpened() const
Expand Down Expand Up @@ -240,14 +162,13 @@ namespace cv {
if (width == 0) width = 640;
if (height == 0) height = 480;

VideoioBridge::getInstance().width = width;
VideoioBridge::getInstance().height = height;
VideoioBridge::getInstance().setWidth(width);
VideoioBridge::getInstance().setHeight(height);

// nb. Mats will be alloc'd on UI thread

// request device init on UI thread - this does not block, and is async
VideoioBridge::getInstance().requestForUIthreadAsync(OPEN_CAMERA,
outArray.size().width, outArray.size().height);
VideoioBridge::getInstance().requestForUIthreadAsync(OPEN_CAMERA);

started = true;
return false;
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11 changes: 0 additions & 11 deletions modules/videoio/src/cap_winrt_capture.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -42,17 +42,6 @@

namespace cv {

/******************* Internal helpers **************************************/

void winrt_updateFrameContainer();
bool winrt_openCamera();
bool winrt_initGrabber(int device, int w, int h);
void winrt_closeGrabber();
void winrt_copyOutput();
void winrt_allocateBuffers(int width, int height);

/******************* VideoCapture_WinRT class ******************************/

class VideoCapture_WinRT : public IVideoCapture
{
public:
Expand Down
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