[thelist] tip

[ashok at magicalkenya.com]

<tip type="Calculating dimensions of JPG and GIF files using VB" author
="Junglee">
When images are stored in a database table as blobs it makes sense to
calculate and store
the original dimensions of the image in the table.   an upload program can
calculate the dimension
of the images , for e.g. in vb it could look like  :

'--code begin
    Dim header As String
    Dim f As Integer
    filename="c:\top_e.gif"
    Open filename For Input As #f
    If Lcase(Right(filename, 3))="gif" Then
         header = Input(10, f)
         Close #f
         wHi = Mid(header, 8, 1)
         wLo = Mid(header, 7, 1)
         hHi = Mid(header, 10, 1)
         hLo = Mid(header, 9, 1)
         w = Asc(wHi) * 256 + Asc(wLo)
         h = Asc(hHi) * 256 + Asc(hLo)
    Elseif Lcase(Right(filename, 3))="jpg" Then
         header = Input(167, f)
         Close #f
         wHi = Asc(Midbp(header, 166, 1))
         wLo = Asc(Midbp(header, 167, 1))
         hHi = Asc(Midbp(header, 164, 1))
         hLo = Asc(Midbp(header, 165, 1))
         w = (wHi) * 256 + (wLo)
         h = (hHi) * 256 + (hLo)
    End If
'--code end
</tip>


------
Ashok Hariharan
http://www.unganisha.org
Disclaimer : The contents of this mail should not be construed as  a "if
you attack me, I'll blast your arse" veiled threat
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