#include <windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

HBITMAP g_bmp;

HBITMAP g_bmpMask;

HBITMAP createImageMask(HBITMAP bitmapHandle, const COLORREF transparencyColor) {

    // For getting information about the bitmap's height and width in this context

    BITMAP bitmap;

    // Create the device contexts for the bitmap and its mask

    HDC bitmapGraphicsDeviceContext = CreateCompatibleDC(NULL);

    HDC bitmapMaskGraphicsDeviceContext = CreateCompatibleDC(NULL);

    // The actual mask

    HBITMAP bitmapMaskHandle;

    // 1. Generate the mask.

    GetObject(bitmapHandle, sizeof(BITMAP), &bitmap);

    bitmapMaskHandle = CreateBitmap(bitmap.bmWidth, bitmap.bmHeight, , , NULL);

    // 2. Setup the device context for the mask (and the bitmap).

    SelectObject(bitmapGraphicsDeviceContext, bitmapHandle);

    SelectObject(bitmapMaskGraphicsDeviceContext, bitmapMaskHandle);

    // 3. Set the background color of the mask.

    SetBkColor(bitmapGraphicsDeviceContext, transparencyColor);

    // 4. Copy the bitmap to the mask and invert it so it blends with the background color.

    BitBlt(bitmapMaskGraphicsDeviceContext, , , bitmap.bmWidth, bitmap.bmHeight, bitmapGraphicsDeviceContext, , , SRCCOPY);

    BitBlt(bitmapGraphicsDeviceContext, , , bitmap.bmWidth, bitmap.bmHeight, bitmapMaskGraphicsDeviceContext, , , SRCINVERT);

    // Clean-up

    DeleteDC(bitmapGraphicsDeviceContext);

    DeleteDC(bitmapMaskGraphicsDeviceContext);

    // Voila!

    return bitmapMaskHandle;

}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)

{

    MSG msg = {  };

    WNDCLASS wc = {  };

    wc.lpfnWndProc = WndProc;

    wc.hInstance = hInstance;

    wc.hbrBackground = (HBRUSH)(COLOR_BACKGROUND);

    wc.lpszClassName = L"minwindowsapp";

    g_bmp = (HBITMAP)LoadImage(hInstance, L"C:\\Users\\h2fM6d9.bmp", IMAGE_BITMAP, , , LR_LOADFROMFILE);

    g_bmpMask = createImageMask(g_bmp, RGB(, , ));

    if (!RegisterClass(&wc))

        return ;

    if (!CreateWindow(wc.lpszClassName,

        L"Minimal Windows Application",

        WS_OVERLAPPEDWINDOW | WS_VISIBLE,

        , , , , , , hInstance, NULL))

        return ;

    while (GetMessage(&msg, NULL, , ) > ) {

        TranslateMessage(&msg);

        DispatchMessage(&msg);

    }

    return ;

}

LRESULT HandleWmPaint(HWND hWnd, WPARAM wParam, LPARAM lParam)

{

    PAINTSTRUCT ps;

    HDC hdcScr = GetDC(NULL);

    HDC hdcBmp = CreateCompatibleDC(hdcScr);

    HBITMAP hbmOld = (HBITMAP)SelectObject(hdcBmp, g_bmp);

    HDC hdcMask = CreateCompatibleDC(hdcScr);

    HBITMAP hbmOldMask = (HBITMAP)SelectObject(hdcMask, g_bmpMask);

    HDC hdc = BeginPaint(hWnd, &ps);

    BitBlt(hdc, , , , , hdcMask, , , SRCCOPY);

    BitBlt(hdc, , , , , hdcBmp, , , SRCCOPY);

    EndPaint(hWnd, &ps);

    SelectObject(hdcMask, hbmOldMask);

    DeleteDC(hdcMask);

    SelectObject(hdcBmp, hbmOld);

    DeleteDC(hdcBmp);

    ReleaseDC(NULL, hdcScr);

    return ;

}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)

{

    switch (message)

    {

    case WM_CLOSE:

        PostQuitMessage();

        break;

    case WM_PAINT:

        return HandleWmPaint(hWnd, wParam, lParam);

    default:

        return DefWindowProc(hWnd, message, wParam, lParam);

    }

    return ;

}