matplotlib-devel

[matplotlib-devel] updated version of the PS backend

[Jochen V. <vo...@se...>]

Hello,

I did some clean-up of the matplotlib PostScript backend.
Main changes:

  - The generated Postscript output is now completely DSC conformant
    (I hope).

  - All PostScript definitions go into a a PostScript dictionary
    mpldict instead of the global one.  This will hopefully prevent
    problems (name clashes) when including matplotlib generated eps
    files into other PostScript files

  - I moved 1.5kb of comments about drawing ellipses from the generated
    PostScript into a Python source code comment.  I think it does not
    make sense to ship the comment in each and every genereated picture.

Hopefully I did not cause any new problems.  Comments about the
changes are most welcome.

All the best,
Jochen
--=20
http://seehuhn.de/

Re: [matplotlib-devel] updated version of the PS backend

[John H. <jdh...@ac...>]

>>>>> "Jochen" == Jochen Voss <vo...@se...> writes:

    Jochen> Hello, I did some clean-up of the matplotlib PostScript
    Jochen> backend.  Main changes:

    Jochen>   - The generated Postscript output is now completely DSC
    Jochen> conformant (I hope).

Great - everyone should take this for a test drive with their favorite
PS viewers before the next release.

    Jochen>   - All PostScript definitions go into a a PostScript
    Jochen> dictionary mpldict instead of the global one.  This will
    Jochen> hopefully prevent problems (name clashes) when including
    Jochen> matplotlib generated eps files into other PostScript files

    Jochen>   - I moved 1.5kb of comments about drawing ellipses from
    Jochen> the generated PostScript into a Python source code
    Jochen> comment.  I think it does not make sense to ship the
    Jochen> comment in each and every genereated picture.

Makes sense to me...

    Jochen> Hopefully I did not cause any new problems.  Comments
    Jochen> about the changes are most welcome.

One other PS quasi-bug you may want to be aware of is the way truetype
fonts are embedded.  The basic problem is that Paul couldn't find a
way to access the individual glyph information so ended up having to
embed the entire font.  For mathtext, with multiple fonts (which is
typical) this makes for large ps files.  It would be nice to just
embed only the required glyphs.  I believe this information is may be
available in face->glyph->outline - see also FT_Outline in the
freetype API abd agg22/font_freetype/agg_font_freetype.cpp which makes
use of this glyph info in decompose_ft_outline.

I haven't looked into this extensively, but I think it should be
possible.  This would help on mathtext for SVG, for which I believe we
require the individual glyph information.

JDH

Re: [matplotlib-devel] updated version of the PS backend

[Jochen V. <vo...@se...>]

Hello John,

On Sun, Oct 31, 2004 at 10:54:04AM -0600, John Hunter wrote:
> One other PS quasi-bug you may want to be aware of is the way truetype
> fonts are embedded.  The basic problem is that Paul couldn't find a
> way to access the individual glyph information so ended up having to
> embed the entire font. ...
Yes, I know about this.  Let's see whether I can do anything ...

It would also be nice if I could find a way to use the printer's built-in
fonts if the user wants to.  This should lead to really small PostScript
files and really high quality printed glyphs.

All the best,
Jochen
--=20
http://seehuhn.de/

Re: [matplotlib-devel] updated version of the PS backend

[John H. <jdh...@ac...>]

>>>>> "Jochen" == Jochen Voss <vo...@se...> writes:

    Jochen> Hello John,
    Jochen> On Sun, Oct 31, 2004 at 10:54:04AM -0600, John Hunter wrote:
    >> One other PS quasi-bug you may want to be aware of is the way
    >> truetype fonts are embedded.  The basic problem is that Paul
    >> couldn't find a way to access the individual glyph information
    >> so ended up having to embed the entire font. ...
    Jochen> Yes, I know about this.  Let's see whether I can do
    Jochen> anything ...

    Jochen> It would also be nice if I could find a way to use the
    Jochen> printer's built-in fonts if the user wants to.  This
    Jochen> should lead to really small PostScript files and really
    Jochen> high quality printed glyphs.

This is effectively what we were doing before we started embedding PS
fonts in matplotlib (0.61 I believe).  So you can check out a CVS
version prior to that and take a look.  It might be nice to support
this as an rc option, to use afm fonts.  matplotlib has an afm parser
and ships with the standard afm files.

JDH