Re: [Pyx-user] Output bitmap to postscript with PyX

[Andre W. <wo...@us...>]

Hi,

On 04.05.04, Markus Meyer wrote:
> this is maybe slightly offtopic, if so, sorry. I'd like to output both
> vector graphics and raster images (bitmaps) using the PyX library and
> output a .PS file I can send to the printer (not an .EPS file). My
> questions are:
> 
> 1. Am I correct that I can output poth .EPS and standard
> printer-friendly .PS postscript files with PyX?

PyX currently creates EPS files, which are valid (single page)
PostScript at the same time. Thus you can just print those files on a
PostScript printer without further efforts. Using the paperformat
option of the writeEPSfile method, you can even center your output on
a specified paper format while keeping the possibility to insert the
EPS file in another document without additional borders etc.

> 2. Is there currently any support (planned) for raster images in PyX?

There are two questions arising here: (2a) inclusion of raster images
and (2b) creation/modification of raster images.

(2a) is an interesting subject, but as far as I can tell, none of the
current developers plans to spend time on that in the near future.
However it would be very nice to have a component, say a
bitmap-module, which allows to insert raster images into a canvas.
This module should be aware and take advantage of certain compression
features available in PostScript. For example, via jpeg2ps it is
possible to build quite efficient PostScript code out of an existing
jpeg image. While currently you can use jpeg2ps to create an EPS file
and include that into PyX (I did that myself already), it would be
nice to have such a functionality available within PyX.

(2b) is clearly out of scope for PyX. However, it could be possible to
use the PIL for that. Once we have (2a) it should be possible to make
use of PIL for creating/modifying some raster images and inserting the
result into PyX within a single python script ...

> 3. If not, what would be the most logical way to add it and/or is it
> possible to send postscript commands in "raw" mode through PyX to get
> this functionality?

The first part of the question is already answered above. About the
second part: It is possible to create a PSCmd, which you can then
insert into a canvas, thus writing arbitrary PostScript yourself.
Its up to you ... ;-)

> If you think PyX is not the right library for this, do you know of any
> other libraries (Python or C) that provide this functionality?

IMHO it just depends on your needs. If you mainly want to take
advantage of the programmable vector graphics system PyX provides and
you just want to insert certain bitmaps, a conversion into of those
bitmap files into PostScript previous to its inclusion into PyX might
work for you.


André

-- 
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