在Windows窗体中显示OpenCV图像

在Windows窗体中显示OpenCV库读取的Mat图像，首先就是将Mat图像转换为Windows认可的BITMAPINFOHEADER数据结构，然后获取相应窗体的HWND句柄。

具体显示函数如下：

void WinShowMatImage(const cv::Mat& img, HDC hdc, const RECT& rect)
{
	CvMat _img = img;
	const CvArr* arr = &_img;
	CvMat stub;
	CvMat* image = cvGetMat(arr, &stub);
	// 构造BITMAPINFO头
	SIZE size = { image->width, image->height };
	int channels = 3;
	BITMAPINFO binfo;
	memset(&binfo, 0, sizeof(binfo));
	BITMAPINFOHEADER& bmih = binfo.bmiHeader;
	bmih.biSize = sizeof(BITMAPINFOHEADER);
	bmih.biWidth = size.cx;
	bmih.biHeight = abs(size.cy);
	bmih.biPlanes = 1;
	bmih.biBitCount = (unsigned short)(channels * 8);
	bmih.biCompression = BI_RGB;

	void* dst_ptr = 0;
	HBITMAP hb = CreateDIBSection(hdc, &binfo, DIB_RGB_COLORS, &dst_ptr, 0, 0);
	HDC windowdc = ::CreateCompatibleDC(hdc);
	SelectObject(windowdc, hb);
	CvMat dst;
	cvInitMatHeader(&dst, size.cy, size.cx, CV_8UC3, dst_ptr, (size.cx*channels + 3)&-4);

	int origin = ((IplImage*)arr)->origin;
	cvConvertImage(image, &dst, origin == 0 ? CV_CVTIMG_FLIP : 0);
	// 显示
	SetStretchBltMode(hdc, COLORONCOLOR);
	//BitBlt( hdc, 0, 0, size.cx, size.cy, windowdc, 0, 0, SRCCOPY );
	StretchBlt(hdc, 0, 0, rect.right - rect.left, rect.bottom - rect.top, windowdc, 0, 0, size.cx, size.cy, SRCCOPY);
}

int _tmain(int argc, _TCHAR* argv[])
{
	Mat img1 = imread("o_1.jpg");
	HWND hwnd = ::GetConsoleWindow();
	RECT rect;
	GetWindowRect(hwnd, &rect);
	WinShowMatImage(img1, ::GetWindowDC(hwnd), rect);
	waitKey(0);
	return 0;
}