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copied!<p>Here, this will do the job. You'll need to ensure you have gdiplus and msimg32 libraries linked for the AlphaBlend (TransparentBlt assumes that a <em>single</em> rgb color in the image will be treated as transparent. I.e it's just 1-bit transparency when using TransparentBlt - fully opaque or fully transparent.)</p> <p>You'll (presumably) wish to use AlphaBlend for this job.</p> <p>Note - I haven't bothered to add an WM_ERASEBKGND to the WndProc function. As a consequence, each time the image is re-drawn, it's drawn straight over the top of what's already there (try resizing the window). Just do a FillRect in erasebkg, and you'll be fine.</p> <p>EDIT: Code updated to use displayImage with a NULL hbitmap to do the background too.</p> <p>Here 'go:</p> <pre><code>#define WIN32_LEAN_AND_MEAN #define WINVER 0x0600 // needed for alphablend function.. #include <windows.h> #include <gdiplus.h> const char g_szClassName[] = "myWindowClass"; // BMP, GIF, JPEG, PNG, TIFF, Exif, WMF, and EMF // requires GDIPlus HBITMAP mLoadImg(WCHAR *szFilename) { HBITMAP result=NULL; Gdiplus::Bitmap* bitmap = new Gdiplus::Bitmap(szFilename,false); bitmap->GetHBITMAP(NULL, &result); delete bitmap; return result; } //void CStaticImg::displayImage(HBITMAP mBmp, HWND mHwnd) void displayImage(HBITMAP mBmp, HWND mHwnd) { RECT myRect; BITMAP bm; HDC screenDC, memDC; HBITMAP oldBmp; BLENDFUNCTION bf; GetObject(mBmp, sizeof(bm), &bm); bf.BlendOp = AC_SRC_OVER; bf.BlendFlags = 0; bf.SourceConstantAlpha = 0xff; bf.AlphaFormat = AC_SRC_ALPHA; screenDC = GetDC(mHwnd); GetClientRect(mHwnd, &myRect); if (mBmp == NULL) FillRect(screenDC, &myRect, WHITE_BRUSH); else { memDC = CreateCompatibleDC(screenDC); oldBmp = (HBITMAP)SelectObject(memDC, mBmp); AlphaBlend (screenDC, 0, 0, myRect.right,myRect.bottom, memDC, 0, 0, bm.bmWidth,bm.bmHeight, bf); SelectObject(memDC, oldBmp); DeleteDC(memDC); ReleaseDC(mHwnd, screenDC); } } // Step 4: the Window Procedure LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) { static HBITMAP myImage; switch(msg) { case WM_CLOSE: DestroyWindow(hwnd); break; case WM_ERASEBKGND: displayImage(NULL, hwnd); break; case WM_CREATE: myImage = mLoadImg(L"bg_shadow_png.png"); break; case WM_PAINT: //displayImage(HBITMAP mBmp, HWND mHwnd); displayImage(myImage, hwnd); ValidateRect(hwnd, NULL); break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hwnd, msg, wParam, lParam); } return 0; } int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { WNDCLASSEX wc; HWND hwnd; MSG Msg; static Gdiplus::GdiplusStartupInput gdiplusStartupInput; static ULONG_PTR gdiplusToken; // so we can load all the image formats that windows supports natively - (I'm using a transparent PNG on the main dialog) GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL); //Step 1: Registering the Window Class wc.cbSize = sizeof(WNDCLASSEX); wc.style = 0; wc.lpfnWndProc = WndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInstance; wc.hIcon = LoadIcon(NULL, IDI_APPLICATION); wc.hCursor = LoadCursor(NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1); wc.lpszMenuName = NULL; wc.lpszClassName = g_szClassName; wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION); if(!RegisterClassEx(&wc)) { MessageBox(NULL, "Window Registration Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK); return 0; } // Step 2: Creating the Window hwnd = CreateWindowEx( WS_EX_CLIENTEDGE, g_szClassName, "The title of my window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 240, 120, NULL, NULL, hInstance, NULL); if(hwnd == NULL) { MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK); return 0; } ShowWindow(hwnd, nCmdShow); UpdateWindow(hwnd); // Step 3: The Message Loop while(GetMessage(&Msg, NULL, 0, 0) > 0) { TranslateMessage(&Msg); DispatchMessage(&Msg); } Gdiplus::GdiplusShutdown(gdiplusToken); return Msg.wParam; } </code></pre>

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