利用FSO取得图像文件信息

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':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
'::: BMP, GIF, JPG and PNG :::
':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
'::: :::
'::: This function gets a specified number of bytes from any :::
'::: file, starting at the offset (base 1) :::
'::: :::
'::: Passed: :::
'::: flnm => Filespec of file to read :::
'::: offset => Offset at which to start reading :::
'::: bytes => How many bytes to read :::
'::: :::
':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
function GetBytes(flnm, offset, bytes)
Dim objFSO
Dim objFTemp
Dim objTextStream
Dim lngSize
on error resume next
Set objFSO = CreateObject("Scripting.FileSystemObject")

' First, we get the filesize
Set objFTemp = objFSO.GetFile(flnm)
lngSize = objFTemp.Size
set objFTemp = nothing
fsoForReading = 1
Set objTextStream = objFSO.OpenTextFile(flnm, fsoForReading)
if offset > 0 then
strBuff = objTextStream.Read(offset - 1)
end if
if bytes = -1 then ' Get All!
GetBytes = objTextStream.Read(lngSize) 'ReadAll
else
GetBytes = objTextStream.Read(bytes)
end if
objTextStream.Close
set objTextStream = nothing
set objFSO = nothing
end function

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'::: :::
'::: Functions to convert two bytes to a numeric value (long) :::
'::: (both little-endian and big-endian) :::
'::: :::
':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
function lngConvert(strTemp)
lngConvert = clng(asc(left(strTemp, 1)) + ((asc(right(strTemp, 1)) * 256)))
end function
function lngConvert2(strTemp)
lngConvert2 = clng(asc(right(strTemp, 1)) + ((asc(left(strTemp, 1)) * 256)))
end function

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'::: :::
'::: This function does most of the real work. It will attempt :::
'::: to read any file, regardless of the extension, and will :::
'::: identify if it is a graphical image. :::
'::: :::
'::: Passed: :::
'::: flnm => Filespec of file to read :::
'::: width => width of image :::
'::: height => height of image :::
'::: depth => color depth (in number of colors) :::
'::: strImageType=> type of image (e.g. GIF, BMP, etc.) :::
'::: :::
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function gfxSpex(flnm, width, height, depth, strImageType)
dim strPNG
dim strGIF
dim strBMP
dim strType
strType = ""
strImageType = "(unknown)"
gfxSpex = False
strPNG = chr(137) & chr(80) & chr(78)
strGIF = "GIF"
strBMP = chr(66) & chr(77)
strType = GetBytes(flnm, 0, 3)
if strType = strGIF then ' is GIF