From 8b7edda6acfb3e71b76cc0f49482fb4c97e96258 Mon Sep 17 00:00:00 2001
From: Alexander Reshetnikov <no@email>
Date: Wed, 22 Feb 2012 13:30:47 +0000
Subject: [PATCH] Added cvShowImage working with handles under Windows.

---
 modules/highgui/src/window_w32.cpp | 77 ++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/modules/highgui/src/window_w32.cpp b/modules/highgui/src/window_w32.cpp
index c52ab8131..6e3007f90 100644
--- a/modules/highgui/src/window_w32.cpp
+++ b/modules/highgui/src/window_w32.cpp
@@ -1452,6 +1452,83 @@ cvShowImage( const char* name, const CvArr* arr )
     __END__;
 }
 
+CV_IMPL void
+cvShowImageHWND(HWND w_hWnd, const CvArr* arr)
+{
+    CV_FUNCNAME( "cvShowImageHWND" );
+
+    __BEGIN__;
+
+    SIZE size = { 0, 0 };
+    int channels = 0;
+    void* dst_ptr = 0;
+    const int channels0 = 3;
+    int origin = 0;
+    CvMat stub, dst, *image;
+    bool changed_size = false;
+    BITMAPINFO tempbinfo;
+    HDC hdc = NULL;
+
+    if( !arr )
+        EXIT;
+    if( !w_hWnd )
+        EXIT;
+
+    hdc = GetDC(w_hWnd);
+
+    if( CV_IS_IMAGE_HDR( arr ) )
+        origin = ((IplImage*)arr)->origin;
+
+	CV_CALL( image = cvGetMat( arr, &stub ) );
+
+    if ( hdc )
+    {
+            //GetBitmapData
+            BITMAP bmp;
+            GdiFlush();
+            HGDIOBJ h = GetCurrentObject( hdc, OBJ_BITMAP );
+
+            if (h == NULL)
+            EXIT;
+            if (GetObject(h, sizeof(bmp), &bmp) == 0) //GetObject(): returns size of object, 0 if error
+            EXIT;
+
+            channels = bmp.bmBitsPixel/8;
+            dst_ptr = bmp.bmBits;
+     }
+
+	if( size.cx != image->width || size.cy != image->height || channels != channels0 )
+    {
+        changed_size = true;
+
+        uchar buffer[sizeof(BITMAPINFO) + 255*sizeof(RGBQUAD)];
+        BITMAPINFO* binfo = (BITMAPINFO*)buffer;
+
+        BOOL bDeleteObj = DeleteObject(GetCurrentObject(hdc, OBJ_BITMAP));
+                CV_Assert( FALSE != bDeleteObj );
+
+        size.cx = image->width;
+        size.cy = image->height;
+        channels = channels0;
+
+        FillBitmapInfo( binfo, size.cx, size.cy, channels*8, 1 );
+
+        HGDIOBJ tempImage = SelectObject( hdc, CreateDIBSection( hdc, binfo, DIB_RGB_COLORS, &dst_ptr, 0, 0));
+    }
+
+    cvInitMatHeader( &dst, size.cy, size.cx, CV_8UC3, dst_ptr, (size.cx * channels + 3) & -4 );
+    cvConvertImage( image, &dst, origin == 0 ? CV_CVTIMG_FLIP : 0 );
+
+    // Image stretching to fit the window
+    RECT rect;
+    GetClientRect(w_hWnd, &rect);
+    int bSuccess = StretchDIBits( hdc, 0, 0, rect.right, rect.bottom, 0, 0, image->width, image->height, dst_ptr, &tempbinfo, DIB_RGB_COLORS, SRCCOPY );
+
+    // ony resize window if needed
+    InvalidateRect(w_hWnd, 0, 0);
+
+    __END__;
+}
 
 CV_IMPL void cvResizeWindow(const char* name, int width, int height )
 {