设置各控件的属性如下：
Form1：AutoRedraw：True
ScaleMode：3
Picture1：AutoRedraw：True
ScaleMode：3
Visible:False
2 代码编写
Modull.bas中的内容（声明BitBlt函数）：
Public Const SRCCOPY=&HCC0020'（DWORD）dest=source
Declare Function BitBlt Lib "gdi32"Alias "BitBlt"(By Val 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
这两句只要从Win32api.txt文件中粘贴即可。
Form1中的代码：
在Declare中定义全局变量：
Const bmpfilemax=5&总共5个bmp文件
Dim bmpfile(bmpfilemax)As String&bmp 文件的文件名数组
Dim drawbmpmode(bmpfilemax) As Integer&各画显示时的切换方式
Dim bmpnum,movestep,xmax,ymax As Integer
Dim kxy As Single &x,y二个方向的比例
程序运行时先作初始化工作：
Private Sub Form-Load ()
bmpnum=0 &当前文件号=0，第一个文件
bmpfile(0)=App.Path+''/bmp1.bmp'' bmpfile(1)=App.Path+''/bmp2.bmp''
bmpfile(2)=App.Path+''/bmp3.bmp''
bmpfile(3)=App.Path+''/bmp4.bmp''
bmpfile(4)=App.Path+''/bmp5.bmp''
drawbmpmode(0)=1
drawbmpmode(1)=5
drawbmpmode(2)=3
drawbmpmode(3)=4
drawbmpmode(4)=2
movestep=0 &步进参数
xmax=Form.ScaleWidth/2
ymax=Form.ScaleHeight/2
kxy =ymax/xmax
Picture1.Picture=LoadPicture(bmpfile(bmpnum))
Timer1.Interval=30 &定时器起动
End Sub
响应鼠标：

Private Sub Form-Click ()
End &当有击鼠标动作时程序结束
End Sub

切换演示工作主要在定时器中完成：
Private Sub Timer1-Timer ()
hDestDC=Form1.HDC&目标DC
hSrcDC=Picture1.hDC&源DC,画是从不可见的Picture1中拷贝到窗体
drawflag =drawbmpmode(bmpnum)&当前画出现的方式
Select Case drawflag
Case 1 &从中间逐步放大
endmax=xmax&用于结束判断
X1=xmax-movestep
w=movestep*2
Y1=Cint(ymax-movestep*kxy)
h=Cint(2*movestep*kxy)
i=BitBlt(hDestDC,X1,Y1,w,h,hSrcDC,X1,Y1,SRCCOPY)
Case 2 &从左到右
endmax=xmax
w=movestep*2
h=Form1.ScaleHeight
i=BitBlt(hDestDC,0,0,w,h,hSrcDC,X1,Y1,SRCCOPY)

Case 3 '左右向中间
endmax=xmax
w=movestep
h=Form1.ScaleHeight
i=BitBlt(hDestDC,0,0,w,h,hSrcDC,0,0,SRCCOPY) &左面部分
X1= Form1.ScaleWidth-movestep
i=BitBlt(hDestDC,X1,0,w,h,hSrcDC,X1,0,SRCCOPY) &左面部分
Case 4 '栅条状
endmax=CInt(2*xmax/10) &共分阶10条
tempi=CInt(2*xmax/10)
w=movestep
h=Form1.ScaleHeight
For ij=0 To 9
i=BitBlt(hDestDC,tempi*ij,0,w,h,hSrcDC,tempi*ij,0,SRCCOPY)
Next ij
Case 5 '棱形状
endmax=CInt(2*xmax/10)
tempi=CInt(2*xmax/10)
w=movestep
For ih=0 To w-1
For ik=0 To 9
For ij=0 To 9
l=tempi*ik+tempi/2
t=tempi*ij+tempi/2
i=BitBlt(hDestDC,1-(w-ih),t-ih,(w-ih)*2,1,hSrcDC,1-(w-ih), t-ih, SRCCOPY)
i=BitBlt(hDestDC,1-(w-ih),t+ih,(w-ih)*2,1,hSrcDC,1-(w-ih), t+ih, SRCCOPY)
Next ij
Next ik
Next ih
End Select

Form1.Refresh

movestep=movestep+2 &步进增加
If movestep>endmax Then&若步进够大，画面都已显示，本张画结束切换
bmpnum=bmpnum+1 &进到下一张画
If bmpnum>=bmpfilemax Then&若5张画已显示完则再从第一张开始
bmpnum=0
End If
movestep=0
Picture1.Picture=LoadPicture(bmpfile(bmpnum))
End If
End Sub

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