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X-Sender: matthew@mail.tangent.com.au
Date: Thu, 23 Apr 1998 02:32:27 +1000
From: "Matthew R. Proctor" <matthew@wolfven.com>
Subject: [asp advanced] GIF/JPG Dimensions

Hi All,

Does anyone know how to dynamically retrieve the HEIGHT and WIDTH of an GIF/JPG? I have a number of images, their locations stored in a database, but I want to be able to retrieve their dimensions so that I can speed up display, and figure out the most appropriate place to display them.

Any ideas?

Matthew

---
Matthew R. Proctor
Imagineering Technology
Melbourne, Australia

From: David Wihl <wihl@softartisans.com>
Subject: RE: [asp advanced] GIF/JPG Dimensions
Date: Wed, 22 Apr 1998 12:50:04 -0400

This works for GIF's only, from the Software Artisans' knowledge base
(http://support.softartisans.com). It does *not* use SA-FileUp :)

Software Artisans Knowledge Base

Product: SAFILEUP Version: 2.0.1
Title: HOWTO: Resizing a GIF image for display
Description:
SA-FileUp is commonly used to upload or download images files. Many customers would like to resize the image upon upload or download.
Corrective Action: This script was supplied by an astute customer, Magnus Lindbergh of CreateIT web agency in Sweden.

Thanks Magnus!
It assumes that the image has been uploaded to a database, but could easily be adapted when the image is uploaded to a file. For use with a file, use ASP's Scripting.FileSystemObject to read the first few bytes of the image.

<%
SQL = "SELECT BLOB "
SQL = SQL & "FROM objectIMAGE WHERE
(((objectIMAGE.imageID)=" &
Request.QueryString("imageID") & "));"
Set Connection = Server.CreateObject("ADODB.Connection")
Set RS = Server.CreateObject("ADODB.RecordSet")
RS.Open SQL, "DSN=DN", 3, 3

Dim BitSet
ReDim BitSet (10)

For I = 0 to 10
BitSet(I) = RS.Fields("BLOB").GetChunk(1)
Next

' Calculate GIF width & height using bit 6-9

width = (256 * AscB(BitSet(7))) + AscB(BitSet(6))
height = (256 * AscB(BitSet(9))) + AscB(BitSet(8))

' Max width / height

MaxWidth = 300
MaxHeight = 200


' Resize the image

iWidth = width
iHeight = height

If iWidth > MaxWidth Then
iHeight = iHeight * maxWidth / iWidth
iWidth = maxWidth

End If

If iHeight > MaxHeight Then
iWidth = iWidth * maxHeight / iHeight
iHeight = maxHeight
End If

' Store Values in Session variables

Session("sWidth") = iWidth
Session("sHeight") = iHeight

%>

This script must be executed before doing the binarywrite. This script will be called from the .asp page after executing the above script.  Using a HTML TAG like:

<img src="resize_gif.asp?imageID=<%=request.querystring("objectID")%>"
width="<%=Cint(Session("sWidth"))%>"
height="<%=Cint(Session("sHeight"))%>">

Note the use of Session("sWidth") & Session("sHeight"), which are calculated in the first script.

resize_gif.asp

<%
MaxSize = 700000
Response.Expires = 0
Response.Buffer = TRUE
Response.Clear
Response.ContentType="image/gif"
Set Connection = Server.CreateObject("ADODB.Connection")
Connection.Open "DSN=DN"
SQLB = "SELECT BLOB FROM objectIMAGE WHERE imageID ="
SQLB = SQLB & Request.QueryString("imageID")
Set rsBlob = Connection.Execute(SQLB)
Response.BinaryWrite rsBlob("BLOB").getChunk(MaxSize)
Response.End
%>

Created:
4/17/98
Last Update:

Article Id:
21


-David

From: Richard Birkby <RBirkby@3s.co.uk>
Subject: RE: [asp advanced] GIF/JPG Dimensions
Date: Wed, 22 Apr 1998 18:33:02 +0100

VBScript has a LoadPicture function, which will return a StdPicture object. This should have Height and Width methods, however they are in OLE_HIMETRIC units.

Now in VB5, I would use ScaleX and ScaleY to convert these. Anyone know how to convert them in VBS?

Richard

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