用渐变色填充背景（二）

void OnEraseBkGnd(HWND hwnd)
{
    /* Vars */
    HDC dc; /* Standard Device Context; used to do the painting */
   
    /* rect = Client Rect of the window;
    Temp = Temparary rect tangle for the color bands */
    RECT rect, temp;
    HBRUSH color; /* A brush to do the painting with */
   
    /* Get the dc for the wnd */
    dc = GetDC(hwnd);
   
    /* Get the client rect */
    GetClientRect(hwnd, &rect);
   
    /* Start color; Change the R,G,B values
    to the color of your choice */
    int r1 = 255, g1 = 0, b1 = 0;
   
    /* End Color; Change the R,G,B values
    to the color of your choice */
    int r2 = 255, g2 = 255, b2 = 0;
   
    /* loop to create the gradient */
    for(int i=0;i<rect.right;i++)
    {
        /* Color ref. for the gradient */
        int r,g,b;
        /* Determine the colors */
        r = r1 + (i * (r2-r1) / rect.right);
        g = g1 + (i * (g2-g1) / rect.right);
        b = b1 + (i * (b2-b1) / rect.right);
       
        /* Fill in the rectangle information */
       
        /* The uper left point of the rectangle
        being painted; uses i as the starting point*/
        temp.left = i;
        /* Upeer Y cord. Always start at the top */
        temp.top = 0;
        /* Okay heres the key part,
        create a rectangle thats 1 pixel wide */
        temp.right = i + 1;
        /* Height of the rectangle */
        temp.bottom = rect.bottom;
       
        /* Create a brush to draw with;
        these colors are randomized */
        color = CreateSolidBrush(RGB(r, g, b));
       
        /* Finally fill in the rectange */
        FillRect(dc, &temp, color);
    }
}

效果：


参考文章：
[1] http://www.codeproject.com/gdi/grad01.asp
Using color gradients as backgrounds in your dialogs and views
By Nishant S
[2] http://www.codetools.com/gdi/win32_gradients.asp
Using Color Gradients in Win32/SDK Programs
By einst992