很多客戶咨詢說網上(shàng)有(yǒu)不少(shǎo)生成縮略圖的(de)ASP組件(jiàn)，若您使用(yòng)的(de)是虛拟空間不支持注冊第三方組件(jiàn)組件(jiàn)，可(kě)能(néng)會(huì)感覺自己的(de)網站失色不少(shǎo)。我們結合網上(shàng)資源寫了個(gè)無組件(jiàn)生成縮略圖程序，僅供參考。還是先看看基礎部分(fēn)吧(ba)。首先，我們知道在頁面中顯示圖片是如(rú)下代碼：
<img src="pic.gif" border="0" width="300" height="260">
　　src是圖片路(lù)徑，border控制(zhì)圖片邊緣寬度，width是圖片的(de)長度，height是圖片的(de)高(gāo)度。縮略圖的(de)生成其實就是在原始尺寸上(shàng)縮放(fàng)。但(dàn)一般爲了盡量少(shǎo)失真，我們都(dōu)會(huì)按比例縮放(fàng)。于是，獲取圖片的(de)長寬尺寸也(yě)就成了生成縮略圖的(de)重點。
　　下面便是編寫無組件(jiàn)生成縮略圖的(de)步驟：
　　1.無組件(jiàn)獲取圖片大(dà)小(xiǎo)
　　利用(yòng)ADODB.stream獲取圖片尺寸的(de)通用(yòng)類
<%
'//////////// GPS：Get Picture Size //////////////
'//////////////利用(yòng)ADODB.stream獲取圖片尺寸//////////////
Class GPS
Dim aso
Private Sub Class_Initialize
Set aso=CreateObject("Adodb.Stream")
aso.Mode=3
aso.Type=1
aso.Open
End Sub

Private Sub Class_Terminate
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 <= LenB(Bin) then Str = Str & Chr(ASCW(MidB(Bin,I,1)&clow))
end If
Next
Bin2Str = Str
End Function

Private Function Num2Str(num,base,lens)
'GPS (2005-8-11)
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)
'GPS (2005-8-11)
dim ret
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)
'GPS (2002-8-11)
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

Private Function BinVal2(bin)
'GPS (2002-8-11)
dim ret
ret = 0
for i = 1 to lenb(bin)
ret = ret *256 + ascb(midb(bin,i,1))
next
BinVal2=ret
End Function

'///以下是調用(yòng)代碼///
Function getImageSize(filespec)
'GPS (2002-8-11)
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)<nBits*4)
binData=aso.Read(1)
sConv=sConv&Num2Str(ascb(binData),2 ,8)
wend
ret(0)="SWF"
ret(1)=int(abs(Str2Num(mid(sConv,1*nBits+1,nBits),2)-Str2Num(mid(sConv,0*nBits+1,nBits),2))/20)
ret(2)=int(abs(Str2Num(mid(sConv,3*nBits+1,nBits),2)-Str2Num(mid(sConv,2*nBits+1,nBits),2))/20)
case "FFD8FF":
do
do: p1=binVal(aso.Read(1)): loop while p1=255 and not aso.EOS
if p1>191 and p1<196 then exit do else aso.read(binval2(aso.Read(2))-2)
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))
case else:
if left(Bin2Str(bFlag),2)="BM" then<b