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20000321: controlling size of gifs

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  • Subject: 20000321: controlling size of gifs
  • Date: Tue, 21 Mar 2000 14:26:23 -0700
>From: address@hidden (Chris Hennon)
>Organization: .
>Keywords: 200003212035.NAA28800

>Can you control the size of gifs in gempak the same as you can with xw?
>The image degrades significantly when I try to shrink it using xv. 
>
>Chris
>
>


Chris,
Yes, the same x;y attributes to the device driver work for gf as well as xw.
For instance, DEVICE=gf|plot.gif|300;200

The imagemagick program "convert" generally does a better job of resizing 
as compared to xv since it resamples the image. However, in resampling the 
image,
the number of colors used increases since where previously you had a red line
on a black background, you would now have many shades of red. The
convert program does have a -colors flag that lets you control how many
colors are used in the image. The severe degredation in xv or browsers
is generally because they just take every Nth pixel of the original image
instead of computing a  shade of the surrounding pixels that get collapsed
into the singular new pixel.

Steve Chiswell