在VISUALBAISC5.0中可以使用播放視頻動(dòng)畫文件（*.AVI）的方法在我們的軟件中加入動(dòng)畫效果,但在軟件中如何實(shí)現(xiàn)視頻畫中畫的效果呢？經(jīng)筆者摸索，發(fā)現(xiàn)利用WIDOWS95的API函數(shù)mciExecute、mciSendString和SetWindowPos可實(shí)現(xiàn)這一效果。
下面筆者以最常用的大畫面中疊加小畫面為例來說明視頻畫中畫的實(shí)現(xiàn)方法。
一、建立窗體。進(jìn)入VISUALBAISC5.0系統(tǒng)環(huán)境，建立一個(gè)新的窗體FORM1。
二、建立視頻窗口。在這里筆者使用了一大一小的兩個(gè)圖畫框（PictureBox）作為視頻窗口。選擇控件工具箱中的PictureBox控件，在窗體中拉出兩個(gè)方框（Picture1和Picture2）。其中Picture1為大畫面，播放AVI01.AVI文件；Picture2為小畫面，播放AVI02.AVI文件。
三、編寫相應(yīng)控件的腳本。
通用模塊：
DeclareFunctionmciExecuteLib"winmm.dll"(ByVallpstrCommandAsString)AsLong
DeclareFunctionmciSendStringLib"winmm.dll"Alias"mciSendStringA"(ByVallpstrCommandAsString,ByVallpstrReturnStringAsString,ByValuReturnLengthAsLong,ByValhwndCallbackAsLong)AsLong
DeclareFunctionSetWindowPosLib"user32"(ByValhwndAsLong,ByValhWndInsertAfterAsLong,ByValxAsLong,ByValyAsLong,ByValcxAsLong,ByValcyAsLong,ByValwFlagsAsLong)AsLong
FORM1的ACTIVATE過程：
DimAAAsLong
DimPlayAviAsLong
DimtmpValAsString
DimKeyValSizeAsLong
OnErrorResumeNext
tmpVal=String$(1024,0)
KeyValSize=1024
PlayAvi=mciSendString("STATUSAVI01READY" Str(Picture2.hwnd),tmpVal,KeyValSize,0)
IfPlayAvi<>263Then
PlayAvi=mciExecute("closeAVI01")
EndIf
tmpVal=String$(1024,0)
KeyValSize=1024
PlayAvi=mciSendString("OPENAVI01.AVIALIASAVI01TYPEAVIVIDEOSTYLECHILDPARENT" Str(Picture2.hwnd) "WAIT",tmpVal,KeyValSize,0)
x1Pos=Picture1.Width
y1Pos=Picture1.Height
tmpVal=String$(1024,0)
KeyValSize=1024
AA=mciSendString("STATUSAVI01WINDOWHANDLEWAIT",tmpVal,KeyValSize,0)
If(Asc(Mid(tmpVal,KeyValSize,1))=0)Then
tmpVal=Left(tmpVal,KeyValSize-1)
Else
tmpVal=Left(tmpVal,KeyValSize)
EndIf
AA=SetWindowPos(tmpVal,0,0,0,x1Pos,y1Pos,0)
AA=mciExecute("WINDOWAVI01STATESHOW")
tmpVal=String$(1024,0)
KeyValSize=1024
PlayAvi=mciSendString("STATUSAVI02READY" Str(Picture1.hwnd),tmpVal,KeyValSize,0)
IfPlayAvi<>263Then
PlayAvi=mciExecute("CLOSEAVI02")
EndIf
tmpVal=String$(1024,0)
KeyValSize=1024
PlayAvi=mciSendString("OPENAVI02.AVIALIASAVI02TYPEAVIVIDEOSTYLECHILDPARENT" Str(Picture1.hwnd) "WAIT",tmpVal,KeyValSize,0)
x1Pos=Picture2.Width
y1Pos=Picture2.Height
tmpVal=String$(1024,0)
KeyValSize=1024
AA=mciSendString("STATUSAVI02WINDOWHANDLEWAIT",tmpVal,KeyValSize,0)
If(Asc(Mid(tmpVal,KeyValSize,1))=0)Then
tmpVal=Left(tmpVal,KeyValSize-1)
Else
tmpVal=Left(tmpVal,KeyValSize)
EndIf
AA=SetWindowPos(tmpVal,0,0,0,x1Pos,y1Pos,0)
MciExecute"WINDOWAVI02STATESHOW"
MciExecute"PLAYAVI01REPEAT"
MciExecute"PLAYAVI02REPEAT"
OnErrorGoTo0
FORM1的QueryUnload過程：
mciExecute"STOPAVI01"
mciExecute"STOPAVI02"
mciExecute"CLOSEAVI01"
mciExecute"CLOSEAVI02"
運(yùn)行此程序可見兩個(gè)動(dòng)畫同時(shí)播放，實(shí)現(xiàn)了視頻畫中畫的效果。以上程序在VISUALBAISC5.0及WINDOWS95中運(yùn)行通過。->
