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Postscript conversion.

Doug Miller dmiller at netcom.com
Fri Apr 1 13:40:09 EST 1994


In article <2nfsiv$96r at ncar.ucar.edu>,
David O. Blanchard <dob at comet.ucar.edu> wrote:
>In article <CnJnDr.s7w at mozo.cc.purdue.edu>,
> <pmiguel at bilbo.bio.purdue.edu> wrote:
>>  What programs exist that (somewhat) intelligently convert a Postscript
>>or EPS file to TIFF or PICT (etc.) so that it can be modified with a 
>>typical graphics program (e.g. MacDraw, Canvas, etc.)?  
>>
>>  By "intelligently" I mean in such a way that text remains text, not 
>>an arbitrary assembly of graphics.
>
>I posted a similar message a few days ago, but have not had much response.
>What I wanted was a Mac program that would convert PostScript to PICT.
>
>If you have access to a Unix machine, you can download the freeware
>package called "ImageMagick".  It contains a program that converts many
>formats in both directions, including PostScript to TIFF.  It claims to
>support PostScript to PICT, but I cannot get a readable PICT.  Supposedly
>the newest version fixes this problem.
>-- 
>+------------------------------------------------------------------------+
>|      David O. Blanchard    dob at comet.ucar.edu   Boulder, Colorado      |
>+------------------------------------------------------------------------+



TIFF is a raster format so any interpretor of PostScript can potentially
create a TIFF.  But after that conversion all you have is pixels, not
graphical objects, so editting is limited to what PhotoShop-type
programs can do.

When you say PICT, be careful, because a PICT file might consist only of
a pixel image (bitmap, pixmap, etc), not graphical objects that can
be manipulated, so just because a routine converts to "PICT" doesn't
mean it is really any different than TIFF.

Fundamentally any arbitrary PostScript file can not be converted to a PICT
file of objects - so PostScript concepts are not directly representable,
such as bezier curves.  Also special effects with text as masks and
objects under them don't represent well.  Not too mention that PostScript
is really a programming language with graphical features, not merely a
graphical file format.


Even if you do get a graphical object PICT, you still don't have the same
thing as a MacDraw file, even though it is possible to edit PICTs in
MacDraw.  For instance, where have your groupings gone?  MacDraw's
native docs keep track of more than is needed to render the file, i.e.
some info used to manipulate the file, but after conversion to PostScript
some of that content is lost, since it isn't needed for rendering, and
you can't really get it back.

So any of these conversion have definite limitations and it is useful to
understand what these are.


-- 
Doug Miller, Los Altos, CA
<dmiller at netcom.com>, <dgmno1 at aol.com>




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