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Re: Using contour in postscripts produces a "stripe" effect? - solved [message #68533] Wed, 04 November 2009 10:13
Andy Heaps is currently offline  Andy Heaps
Messages: 22
Registered: March 2006
Junior Member
How do you mean fix this? The postscript doesn't have the problem,
there's nothing wrong with it.

The problem is that when you want to create an image (bitmap) for quick
viewing or for sharing on a web page you get the white line effect when
using anti-aliasing. So you have a choice when making an image using
ImageMagick convert from a postscript file:

a) you have the white lines and the fonts and lines are smoothed.
b) you have no white lines and the fonts and lines look stepped
aka 'the jaggies'

You can increase the density of the output picture and this reduces the
look of the stepped effect in the fonts and lines:
convert -density 300 +antialias idl.ps idl.png

Cheers
Andy



pp wrote:
> On Nov 4, 9:42 am, Andy Heaps <a.j.he...@reading.ac.uk> wrote:
>> Linux, Solaris and Mac
>> convert +antialias idl.ps idl.png
>> convert +antialias idl.ps idl.pdf
>>
>
> But this turns nice vector ps files into bitmaps. I am wondering how
> to fix this without making bitmaps.
Re: Using contour in postscripts produces a "stripe" effect? - solved [message #68538 is a reply to message #68533] Wed, 04 November 2009 07:21 Go to previous message
penteado is currently offline  penteado
Messages: 866
Registered: February 2018
Senior Member
Administrator
On Nov 4, 9:42 am, Andy Heaps <a.j.he...@reading.ac.uk> wrote:
>
> Linux, Solaris and Mac
> convert +antialias  idl.ps idl.png
> convert +antialias  idl.ps idl.pdf
>

But this turns nice vector ps files into bitmaps. I am wondering how
to fix this without making bitmaps.
Re: Using contour in postscripts produces a "stripe" effect? - solved [message #68539 is a reply to message #68538] Wed, 04 November 2009 07:15 Go to previous message
Andy Heaps is currently offline  Andy Heaps
Messages: 22
Registered: March 2006
Junior Member
Hi David,
yes, please feel free to take anything you like. The original
query to ITT-VIS technical support is at
http://ncas-climate.nerc.ac.uk/ajh/white_lines/white_lines.h tml
and has a couple of nice images from Illustrator showing a close up of
the white lines and the postscript objects.

Cheers
Andy





David Fanning wrote:
> Andy Heaps writes:
>
>> A sample IDL colour filled contour postscript file and the PNG output from
>> convert -trim idl.ps idl.png
>> run on a Linux box are available at:
>> http://ncas-climate.nerc.ac.uk/ajh/white_lines/cylin3.ps
>> http://ncas-climate.nerc.ac.uk/ajh/white_lines/cylin3.png
>
> Andy, can I have permission to use these files for an
> article about this on my web page?
>
> Cheers,
>
> David
>
>
Re: Using contour in postscripts produces a "stripe" effect? - solved [message #68542 is a reply to message #68539] Wed, 04 November 2009 06:04 Go to previous message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
Andy Heaps writes:

> A sample IDL colour filled contour postscript file and the PNG output from
> convert -trim idl.ps idl.png
> run on a Linux box are available at:
> http://ncas-climate.nerc.ac.uk/ajh/white_lines/cylin3.ps
> http://ncas-climate.nerc.ac.uk/ajh/white_lines/cylin3.png

Andy, can I have permission to use these files for an
article about this on my web page?

Cheers,

David


--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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