asp获取图片宽度和高度的类.doc

% 获取图片宽度和高度的类，支持JPG，GIF，PNG，BMP Class ImgWHInfo Dim ASO Private Sub Class_Initialize Set ASO=Server.CreateObject(ADODB.Stream) ASO.Mode=3 ASO.Type=1 ASO.Open End SubPrivate Sub Class_Terminate Err.Clear Set ASO=Nothing End Sub Private Function Bin2Str(Bin) Dim I, Str For I=1 To LenB(Bin) clow=MidB(Bin,I,1) If ASCB(clow)128 Then Str = Str & Chr(ASCB(clow) Else I=I+1 If I =Base) Ret = (Num Mod Base) & Ret Num = (Num - Num Mod Base)/Base Wend Num2Str = Right(String(Lens,0) & Num & Ret,Lens) End Function Private Function Str2Num(Str,Base) Dim Ret,I Ret = 0 For I=1 To Len(Str) Ret = Ret *base + Cint(Mid(Str,I,1) Next Str2Num=Ret End Function Private Function BinVal(Bin) Dim Ret,I Ret = 0 For I = LenB(Bin) To 1 Step -1 Ret = Ret *256 + AscB(MidB(Bin,I,1) Next BinVal=Ret End Function Private Function BinVal2(Bin) Dim Ret,I Ret = 0 For I = 1 To LenB(Bin) Ret = Ret *256 + AscB(MidB(Bin,I,1) Next BinVal2=Ret End Function Private Function GetImageSize(filespec) Dim bFlag Dim Ret(3) ASO.LoadFromFile(filespec) bFlag=ASO.Read(3) Select Case Hex(binVal(bFlag) Case 4E5089: ASO.Read(15) ret(0)=PNG ret(1)=BinVal2(ASO.Read(2) ASO.Read(2) ret(2)=BinVal2(ASO.Read(2) Case 464947: ASO.read(3) ret(0)=gif ret(1)=BinVal(ASO.Read(2) ret(2)=BinVal(ASO.Read(2) Case 535746: ASO.read(5) binData=ASO.Read(1) sConv=Num2Str(ascb(binData),2 ,8) nBits=Str2Num(left(sConv,5),2) sConv=mid(sConv,6) While(len(sConv)191 And p1196 Then Exit Do Else ASO.read(binval2(ASO.Read(2)-2) Do:p1=binVal(ASO.Read(1):Loop While p10 and H10 thenif W1350 thenW=350H=H1*350/W1elseW=W1H=H1en