用bitblt繪制實(shí)心矩形成了點(diǎn)圖

#include <windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPreInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("figure");
    MSG msg;
    HWND hwnd;
    WNDCLASS wndclass;

    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;

    if (!RegisterClass(&wndclass))
    {
        return 0;
    }

    hwnd = CreateWindow(szAppName, TEXT("Figure"),
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        CW_USEDEFAULT, CW_USEDEFAULT,
        NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    HDC mdc;
    HBITMAP bmap;
    HBRUSH hbrush;
    int w, h;

    switch (message)
    {
    case WM_CREATE:
        return 0;
    case WM_PAINT:
        hdc = GetDC(hwnd);

        RECT rect;
        GetClientRect(hwnd, &rect);
        w = rect.right - rect.left;
        h = rect.bottom - rect.top;

        mdc = CreateCompatibleDC(hdc);
        bmap = CreateCompatibleBitmap(mdc, w, h);

        SelectObject(mdc, bmap);
        hbrush = CreateSolidBrush(RGB(240, 240, 240));
        FillRect(mdc, &rect, hbrush);

        BitBlt(hdc, 0, 0, w, h, mdc, 0, 0, SRCCOPY);

        DeleteObject(hbrush);
        DeleteObject(bmap);
        ReleaseDC(hwnd, mdc);
        ReleaseDC(hwnd, hdc);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}