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Eps jaggies

Posted: 2008-04-10T03:17:35-07:00
by webmagick
I have compiled IM6.4.0 with libtiff 3.82, ghostscript 8.62 gpl and libpng 1.2.25 on my Intel MacBook
I get very jagged images converting from eps to jpg/png

Code: Select all

Image: 149732.eps
Format: EPT (Encapsulated PostScript with TIFF preview)
Class: DirectClass
Geometry: 198x510+0+0
Base geometry: 827x2126
Resolution: 72x72
Print size: 2.75x7.08333
...
This will get jagged when converted to jpg - even if not resized
Maybe because the page is smaller than the base geometry?
Is this a bug and is there a workaround?

Re: Eps jaggies

Posted: 2008-04-10T07:00:29-07:00
by magick
Try this command:
  • convert -density 400 image.ept -resize 25% image.png

Re: Eps jaggies

Posted: 2008-04-10T07:37:52-07:00
by webmagick
That worked - why doesn' it do this by default?
Should this conversion method be used with every eps?

Re: Eps jaggies

Posted: 2008-04-10T09:13:29-07:00
by magick
A design principle of ImageMagick is to keep operations atomic and let the user decide how to smartly apply the atomic operations. In the EPS example, adding the density and resize operations is known as supersampling. Not everyone may want supersampling so its an option in ImageMagick. As far as applying this method to all EPS files-- well that's up to you.

Re: Eps jaggies

Posted: 2008-04-11T02:59:52-07:00
by webmagick
I am not sure what supersampling has to do with this exactly. Not if it is a 1:1 conversion.
It seems that the eps is like a document with the full original image data embedded but has smaller page setting effectively downscaling the image?
Photoshop just handles it in another way - what is correct?
1:1 conversion Imagemagick: http://server.imento.dk/im.jpg
1:1 conversion Photoshop: http://server.imento.dk/ps.jpg
IM treats the eps as 198 x 510
PS treats the eps as 827 x 2126