Capture Image from Secondary Monitor, cropping, and saving - c++

Question

I'm trying to write an application that takes a screen shot of an area on one of the monitors and saves it to an image. The Screen shot should be taken at a x,y coordinate with a given width and height. When the image saves it should be saved at 0,0 and the same width height. I have this working on my main monitor but when I attempt to take the screen shot of my 2nd or 3rd monitor it doesnt work. I either get a black image or a file that when opened says its an invalid format.
My code is a modified version of the following code that takes a screen shot of the entire desktop.
https://github.com/GERD0GDU/dxgi_desktop_capture
Main Monitor width/height
2560 X 1440
Main monitor top corner x/y coordinates are 0,0 retrieved by calling
POINT cursorPos;
GetCursorPos(&cursorPos);
Secondary Monitor width/height
1080 x 1920
Secondary monitor top corner x/y coordinates are 2560,-238
For reference for my image coordinates that work on the main monitor i'm passing in x:801 y:227, width:1756, height:1115
For my 2nd monitor which sits to the right of my main monitor and is flipped sideways making it taller than wide I'm passing in x:2907 y:-11 width:737 height:1595
HRESULT CDXGICapture::CaptureToFile(_In_ LPCWSTR lpcwOutputFileName, int x, int y, int width, int height)
{
AUTOLOCK();
if (!m_bInitialized) {
return D2DERR_NOT_INITIALIZED;
}
CHECK_POINTER_EX(m_ipDxgiOutputDuplication, E_INVALIDARG);
CHECK_POINTER_EX(lpcwOutputFileName, E_INVALIDARG);
HRESULT hr = S_OK;
hr = DXGICaptureHelper::IsRendererInfoValid(&m_rendererInfo);
if (FAILED(hr)) {
return hr;
}
// is valid?
hr = DXGICaptureHelper::GetContainerFormatByFileName(lpcwOutputFileName);
if (FAILED(hr)) {
return hr;
}
DXGI_OUTDUPL_FRAME_INFO FrameInfo;
CComPtr<IDXGIResource> ipDesktopResource;
CComPtr<ID3D11Texture2D> ipAcquiredDesktopImage;
CComPtr<ID2D1Bitmap> ipD2D1SourceBitmap;
// Get new frame
int lTryCount = 4;
do
{
Sleep(1);
hr = m_ipDxgiOutputDuplication->AcquireNextFrame(250, &FrameInfo, &ipDesktopResource);
if (SUCCEEDED(hr))
break;
if (hr == DXGI_ERROR_WAIT_TIMEOUT)
{
continue;
}
else if (FAILED(hr))
break;
} while (--lTryCount > 0);
if (hr == DXGI_ERROR_WAIT_TIMEOUT)
{
return S_FALSE;
}
else if (FAILED(hr))
{
return hr;
}
// QI for ID3D11Texture2D
hr = ipDesktopResource->QueryInterface(IID_PPV_ARGS(&ipAcquiredDesktopImage));
ipDesktopResource = nullptr;
CHECK_HR_RETURN(hr);
if (nullptr == ipAcquiredDesktopImage)
{
// release frame
m_ipDxgiOutputDuplication->ReleaseFrame();
return E_OUTOFMEMORY;
}
// Copy needed full part of desktop image
m_ipD3D11DeviceContext->CopyResource(m_ipCopyTexture2D, ipAcquiredDesktopImage);
// release frame
hr = m_ipDxgiOutputDuplication->ReleaseFrame();
CHECK_HR_RETURN(hr);
// create D2D1 source bitmap
hr = DXGICaptureHelper::CreateBitmap(m_ipD2D1RenderTarget, m_ipCopyTexture2D, &ipD2D1SourceBitmap);
CHECK_HR_RETURN(hr);
//try this
D2D1_RECT_F rcSource = D2D1::RectF(
(FLOAT)x,
(FLOAT)y,
(FLOAT)x + width,
(FLOAT)y+ height);
D2D1_RECT_F rcTarget = D2D1::RectF(
(FLOAT)0,
(FLOAT)0,
(FLOAT)width,
(FLOAT)height);
D2D1_POINT_2F ptTransformCenter = D2D1::Point2F(width / 2.0f, height / 2.0f);
// Apply the rotation transform to the render target.
D2D1::Matrix3x2F rotate = D2D1::Matrix3x2F::Rotation(
m_rendererInfo.RotationDegrees,
ptTransformCenter
);
D2D1::Matrix3x2F scale = D2D1::Matrix3x2F::Scale(
D2D1::SizeF(1, 1),
ptTransformCenter
);
// Priority: first rotate, after scale...
m_ipD2D1RenderTarget->SetTransform(rotate * scale);
m_ipD2D1RenderTarget->BeginDraw();
// clear background color
m_ipD2D1RenderTarget->Clear(D2D1::ColorF(D2D1::ColorF::White, 1.0f));
m_ipD2D1RenderTarget->DrawBitmap(ipD2D1SourceBitmap, rcTarget, 1.0f, D2D1_BITMAP_INTERPOLATION_MODE_LINEAR, rcSource);
//m_ipD2D1RenderTarget->SetTransform(D2D1::Matrix3x2F::Identity());
hr = m_ipD2D1RenderTarget->EndDraw();
if (FAILED(hr)) {
return hr;
}
hr = DXGICaptureHelper::SaveImageToFile(m_ipWICImageFactory, m_ipWICOutputBitmap, lpcwOutputFileName, width, height);
if (FAILED(hr)) {
return hr;
}
return S_OK;
} // CaptureToFile
My save to file method
static
COM_DECLSPEC_NOTHROW
inline
HRESULT
SaveImageToFile(
_In_ IWICImagingFactory* pWICImagingFactory,
_In_ IWICBitmapSource* pWICBitmapSource,
_In_ LPCWSTR lpcwFileName,
_In_ unsigned int uiWidth,
_In_ unsigned int uiHeight
)
{
CHECK_POINTER_EX(pWICImagingFactory, E_INVALIDARG);
CHECK_POINTER_EX(pWICBitmapSource, E_INVALIDARG);
HRESULT hr = S_OK;
GUID guidContainerFormat;
hr = GetContainerFormatByFileName(lpcwFileName, &guidContainerFormat);
if (FAILED(hr)) {
return hr;
}
WICPixelFormatGUID format = GUID_WICPixelFormatDontCare;
CComPtr<IWICImagingFactory> ipWICImagingFactory(pWICImagingFactory);
CComPtr<IWICBitmapSource> ipWICBitmapSource(pWICBitmapSource);
CComPtr<IWICStream> ipStream;
CComPtr<IWICBitmapEncoder> ipEncoder;
CComPtr<IWICBitmapFrameEncode> ipFrameEncode;
// unsigned int uiWidth = 1756;
// unsigned int uiHeight = 1115;
hr = ipWICImagingFactory->CreateStream(&ipStream);
if (SUCCEEDED(hr)) {
hr = ipStream->InitializeFromFilename(lpcwFileName, GENERIC_WRITE);
}
if (SUCCEEDED(hr)) {
hr = ipWICImagingFactory->CreateEncoder(guidContainerFormat, NULL, &ipEncoder);
}
if (SUCCEEDED(hr))
{
hr = ipEncoder->Initialize(ipStream, WICBitmapEncoderNoCache);
}
if (SUCCEEDED(hr))
{
hr = ipEncoder->CreateNewFrame(&ipFrameEncode, NULL);
}
if (SUCCEEDED(hr))
{
hr = ipFrameEncode->Initialize(NULL);
}
if (SUCCEEDED(hr))
{
hr = ipFrameEncode->SetSize(uiWidth, uiHeight);
}
if (SUCCEEDED(hr))
{
hr = ipFrameEncode->SetPixelFormat(&format);
}
if (SUCCEEDED(hr))
{
hr = ipFrameEncode->WriteSource(ipWICBitmapSource, NULL);
}
if (SUCCEEDED(hr))
{
hr = ipFrameEncode->Commit();
}
if (SUCCEEDED(hr))
{
hr = ipEncoder->Commit();
}
return hr;
} // SaveImageToFile

Answer 1

The coordinates being passed in needed to be normalized to the monitor by itself without considering the other monitors. IE all x and y values needed to be positive from a 0,0 being the top left of the monitor.
To get the coordinates for a monitor I used the following where the Control is the view I was trying to capture within my application.
Monitor[] monitors = Display.getDefault().getMonitors();
Control control = getScreenCaptureControlArea();
Point p = control.toDisplay(0, 0);
for (Monitor monitor : monitors) {
Rectangle bounds = monitor.getBounds();
if (monitor.getBounds().contains(p.x, p.y)) {
setxCord(Math.abs(Math.abs(bounds.x) - Math.abs(p.x)));
setyCord(Math.abs(Math.abs(bounds.y) - Math.abs(p.y)));
setWidth(control.getSize().x);
setHeight(control.getSize().y);
break;
}
}
Will note that this still doesnt work when the monitor is in Portrait mode as the image saved is incorrect. But seeing as my application isnt meant to be used in a Portrait mode it didnt matter much so i didnt put any more effort into figuring out that problem.