不使用组件如何自动生成JPG缩略图？ - 编程论坛

现在做一个页面需要很多图片。问题是服务器上没有图片组件。仅仅是FSO和ADO。
请问有没有办法用ASP 自动生成一个小的图片？否则一个页面下载的太慢了。

附下面的代码是获取图片文件的宽和高的

程序代码：

<%
Class DealImgSize
Dim aso
' 初始化
Private Sub Class_Initialize
    Set aso = CreateObject("ADODB.Stream")
    aso.Mode = 3
    aso.Type = 1
    aso.Open
End Sub

'结束对象
Private Sub Class_Terminate
    Set aso =Nothing
End Sub

Private Function Bin2Str(Bin)
    Dim i,str, clow
    For i =1 to LenB(Bin)   '字节长度,Unicode是双字节的
    clow =MidB(Bin,i,1) '取得i开始的1个字节
    If AscB( clow ) < 128 Then '如果首字节的ascii码小于128则将其放入到str字符串中
        str = str & Chr(ASCB( clow ))
    Else
        i = i + 1 '如果当前大于等于128，则处理下一个
        If i <= LenB(Bin ) Then str = str & Chr(ASCW(Mid(Bin,i,1)&clow))
    End If
    Next
End Function

Private Function Num2Str(num,base,lens)
    Dim ret
    ret = ""
    While (num >=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
    ret = 0
    For i  = 1 To len(str)
        ret = ret * base + Cint (Mid(str,i,1))
    Next

    Str2Num = ret
End Function

' 将bin按字节使用ASCII编码返回（倒序）
Private Function BinVal( bin )
    Dim ret
    ret = 0
    For i = lenb( bin )  to  1  step -1
        ret = ret * 256 + ascb(midb(bin,i,1))
    Next
    BinVal = ret
End Function

' 将bin按字节使用ASCII编码返回
Private Function BinVal2( bin )
    Dim ret
    For i =1 To lenb(bin)
        ret = ret*256 + Ascb(Midb(bin , i , 1) )
    Next
    BinVal2 = ret
End Function

' 以下是调用代码
Function getImageSize( filespec )
    Dim ret(3)
    aso.LoadFromFile ( filespec )
    bFlag = aso.read(3)
    Select Case hex(BinVal(bFlag))
        case "4E5089": 'PNG图前3个字节是  89 50 4E
        aso.read(15)
        ret(0) = "PNG"
        ret(1) = BinVal2(aso.Read(2)) '读取宽度
        aso.Read(2) '空2个字节
        ret(2) = BinVal2(aso.Read(2)) '读取高度

    Case "464947":
        aso.Read(3)
        ret(0) = "GIF"
        ret(1) = BinVal(aso.Read(2))
        ret(2) = BinVal(aso.Read(2))
    Case "FFD8FF":
    Do
        Do
            p1 = BinVal( aso.Read(1) )
        Loop While  p1 = 255 And Not aso.EOS  '如果是FF就继续读下一个字节

        If p1>191 and p1 < 196 Then  '如果是C0,C1,C2,C3则退出
            Exit Do
        Else
            aso.Read( BinVal2(aso.Read(2))-2)
        End If

        Do
            p1 = binVal(aso.Read(1))
        Loop While p1<255 And Not aso.EOS
    Loop While True
    aso.Read(3)
    ret(0) = "JPG"
    ret(2) = BinVal2( aso.Read(2))
    ret(1) = BinVal2( aso.Read(2))

    End Select
    ret(3) = "width="""& ret(1) & """ heigth= """& ret(2) & """

    getImageSize = ret

End Function

End Class

%>

[ 本帖最后由 willstier 于 2010-3-9 13:22 编辑 ]