VB实现窗口图像缩放、滚动技巧

p;     FileName="C:\SAMP.BMP"
        Open FileName For Binary As #1
        Get #1,19,ImageWidth:Get#1,,ImageHeight        ''读取位图的宽度和高度
        Close #1
        DW=15*ImageWidth-ImageWin.Width           ''将像点转换为Twip(微点)
        DH=15*ImageHeight-ImageWin.Height
        ImageWin.Width=15*ImageWidth
        ImageWin.Height=15*ImageHeight
        AppImage.Autoredraw=True
        AppImage.Caption=FileName           ''改变Form窗标题
        HScroll1.SmallChange=100            ''设置滚动最小步距
        VScroll1.SmallChange=100
        DX=ImageWin.Width:DY=ImageWin.Height            ''设置复制图像尺寸
        SX=ImageWin.Width:SY=ImageWin.Height
        AMP=1''设置缩放比例为1
        sWin=GetDesktopWindow()                    ''获取桌面窗口句柄
        sDC=GetDC(sWin)                                    ''转换为描述表句柄
        hd=BitBlt(ImageWin.hdc,0,0,Image.Width,Image.Height,sDC,0,0,&HCC0020)
        hd=ReleaseDC(sWin,sDC)                    ''释放窗口描述表
        AppImage.ImageWin=LoadPicture(FileName)            ''载入图像显示
End Sub

3.在General对象的Declaration过程中声明本程序所使用的WIN95 API函数和和过程,以及各事件程序所使用的全局变量等。
    Private Declare Function BitBlt Lib "gdi32"(ByVal hDestDC As Long,ByVal X As Long,ByVal Y As Long,ByVal nWidth As     Long,ByVal nHeight As Long,ByVal hSrcDC As Long,ByVal xSrc As Long,ByVal ySrc As Long,ByVal dwRop As Long) As Long
Private Declare Function GetDC Lib "