xmlroff-list

[xmlroff] Cairo backend: close, very, very close

[Tony G. <Ton...@Su...>]

I have added a Cairo backend that is very close to working correctly, at least
for PostScript output.

If you like the raw, bleeding edge, then you can check out the current code
from CVS.

You will get more visible results if you run autogen.sh with the
'--disable-clip' argument:

   ./autogen.sh --disable-clip

A good sample to try it on is the testsuite file
property/border-padding-background/background-color1.fo

(FYI, I have so far only run the current xmlroff from my workspace and haven't
tried installing it.)

For those of you who can't take the suspense of waiting until you've updated
your xmlroff workspace and rebuilt, the Cairo PostScript output currently has
the Y-axis reversed: what should be at the top of the page appears at the
bottom, and vice-versa.  The text, however, is the right way up, but it also
happens to not coincide with its background.

So far the PDF output is failing because the layouts apparently have zero
lines of text.

Regards,


Tony.

Re: [xmlroff] Cairo backend: close, very, very close

[Stefan S. <se...@sy...>]

Tony Graham wrote:
> I have added a Cairo backend that is very close to working correctly, at least
> for PostScript output.

Very cool ! What about some little architecture / high-level design document
showing how all this fits together ? What is cairo, actually ? I remember it
being some vector graphics rendering engine related to the XFree86 project.
Is this still accurate ? Is it a library users need to install and which xmlroff
checks for in configure ? What exactly does this cairo backend replace ?

Thanks a lot !

		Stefan

Re: [xmlroff] Cairo backend: close, very, very close

[Tony G. <Ton...@Su...>]

Stefan Seefeld <se...@sy...> writes:
> Tony Graham wrote:
>> I have added a Cairo backend that is very close to working correctly, at least
>> for PostScript output.
>
> Very cool ! What about some little architecture / high-level design document
> showing how all this fits together ? What is cairo, actually ? I remember it

You want documentation?  Don't you know this is an open-source project?

I'll see what I can do.

> being some vector graphics rendering engine related to the XFree86 project.
> Is this still accurate ? Is it a library users need to install and which xmlroff
> checks for in configure ? What exactly does this cairo backend replace ?

Cairo (http://www.cairographics.org) is the next Big Thing for free software
to use for rendering.

It's also required for recent Pango builds, so sooner or later it will be on
every machine that has GNOME anyway.

configure checks both for Cairo and for a recent enough version of Pango,
since you need both.  If you disable Cairo, the required Pango version reverts
to 1.6 or so.

Cairo looks like the best way to get SVG support in xmlroff, since lots of
people seem to be hooking libsvg up to Cairo.  I haven't looked into the
details, but it would be an ideal task for someone who is interested in SVG
support.

The Cairo backend doesn't (yet) replace anything.  It's currently an
alternative to the GNOME Print default.

Regards,


Tony.

Re: [xmlroff] Cairo backend: close, very, very close

[Stefan S. <se...@sy...>]

Tony Graham wrote:
> Stefan Seefeld <se...@sy...> writes:
> 
>>Tony Graham wrote:
>>
>>>I have added a Cairo backend that is very close to working correctly, at least
>>>for PostScript output.
>>
>>Very cool ! What about some little architecture / high-level design document
>>showing how all this fits together ? What is cairo, actually ? I remember it
> 
> 
> You want documentation?  Don't you know this is an open-source project?

:-)

> I'll see what I can do.

Thanks !

>>being some vector graphics rendering engine related to the XFree86 project.
>>Is this still accurate ? Is it a library users need to install and which xmlroff
>>checks for in configure ? What exactly does this cairo backend replace ?
> 
> 
> Cairo (http://www.cairographics.org) is the next Big Thing for free software
> to use for rendering.

Ok, thanks.


> The Cairo backend doesn't (yet) replace anything.  It's currently an
> alternative to the GNOME Print default.

I see. So it would provide support for features not currently supported
in GNOME Print (such as transparent / translucent graphics) ?

Thanks,
		Stefan

Re: [xmlroff] Cairo backend: close, very, very close

[Tony G. <Ton...@Su...>]

Stefan Seefeld <se...@sy...> writes:
> Tony Graham wrote:
...
>> The Cairo backend doesn't (yet) replace anything.  It's currently an
>> alternative to the GNOME Print default.
>
> I see. So it would provide support for features not currently supported
> in GNOME Print (such as transparent / translucent graphics) ?

It has more support for transparency than I know what to do with.

Here's a snippet from the docs:

------------------------------------------------------------
void        cairo_set_source_rgb            (cairo_t *cr,
                                             double red,
                                             double green,
                                             double blue);
void        cairo_set_source_rgba           (cairo_t *cr,
                                             double red,
                                             double green,
                                             double blue,
                                             double alpha);
void        cairo_set_source                (cairo_t *cr,
                                             cairo_pattern_t *source);
void        cairo_set_source_surface        (cairo_t *cr,
                                             cairo_surface_t *surface,
                                             double x,
                                             double y);
cairo_pattern_t* cairo_get_source           (cairo_t *cr);
------------------------------------------------------------

You can set the transparency of the colour, and, it appears, you can draw with
patterns and graphics.

Regards,


Tony.

P.S. What version of libgnomeprint are you using now?  I read in the
libgnomeprint ChangeLog that transparency in PDF was fixed in a recent
release.

Re: [xmlroff] Cairo backend: close, very, very close

[Stefan S. <se...@sy...>]

Tony Graham wrote:

> P.S. What version of libgnomeprint are you using now?  I read in the
> libgnomeprint ChangeLog that transparency in PDF was fixed in a recent
> release.

That is good to know. I'm still running FC3 on my laptop. May be I'll
consider upgrading once FC5 is out...

Thanks,
		Stefan