透明方式叠加图象

p;dcCompatible = CreateCompatibleDC(Picture1.hdc)
     
    bm = CreateCompatibleBitmap(Picture1.hdc, Picture1.Width \ 15, _
        Picture1.Height \ 15)
     
    pBitmapOld = SelectObject(dcCompatible, bm)
    rectTemp.Left = 0: rectTemp.Top = 0
    rectTemp.Right = Picture1.Width \ 15: rectTemp.Bottom = _
        Picture1.Height \ 15
    tLog.lbColor = gColor
    tLog.lbStyle = BS_SOLID
    tLog.lbHatch = 0
    lBrush = CreateBrushIndirect(tLog)
    FillRect dcCompatible, rectTemp, lBrush
    BitBlt Picture1.hdc, 0, 0, Picture1.Width \ 15, _
        Picture1.Height \ 15, dcCompatible, 0, 0, SRCAND
    SelectObject dcCompatible, pBitmapOld

    BitBlt Picture1.hdc, 0, 0, Picture1.Width \ 15, _
        Picture1.Height \ 15, Picture2.hdc, 0, 0, SRCPAINT
    DeleteDC dcCompatible
End Sub
    运行程序，点击Command1，你就可以看到Picture2上的图象叠加到了Picture1上面了。改变上面
源程序中的 Const gColor = &HFFFFFF 一句中的gColor的值（在0到&HFFFFFFFF间变动），就可以
使图象的叠加产生不同的透明效果。
    以上程序在Win98、VB6.0下运行通过。