[cairo] Cairo and SVG

[Behdad Esfahbod]

Hi Alan,

There are two different issues: rendering an SVG file to screen or other
mediums, and rendering using cairo to an SVG file.  The former is done
by librsvg, the latter by cairo's SVG backend.

If you have problems using the SVG backend, you should report them on
bugs.freedesktop.org or here on this list, or no one will notice them.

behdad

On Fri, 2007-12-21 at 12:37 -0800, Alan W. Irwin wrote:
> On 2007-12-21 14:20-0500 Behdad Esfahbod wrote:
> 
> > On Fri, 2007-12-21 at 14:05 -0500, Jake B wrote:
> >> Hi, I'm wondering if anyone could tell me, are there any projects that
> >> are currently trying to implement SVG using Cairo?
> >> Please let me know. Thanks.
> >
> > Search for librsvg, if rendering is what you mean by implementing SVG.
> 
> My knowledge of Cairo is limited (only what I can pick up from the
> cairo-related devices that have been implemented by somebody else for PLplot
> and from lurking on list here for a while) so please bear with me. The
> PLplot cairo devices code does implement a svgcairo device that calls
> cairo_svg_surface_create_for_stream. Looking over the relevant Debian
> package dependencies for libcairo2-dev, I cannot find any mention of
> librsvg, but it may be in one of the longer dependency chains that I didn't
> explore.
> 
> Note, it appears that SVG backend (I hope I am using the correct terminology
> here) is not nearly as well supported as the PS, PDF, PNG, and X backends.
> Our cairo devices are implemented almost entirely with common code with only
> minimal variations for each backend (e.g., calls to such functions as
> cairo_svg_surface_create_for_stream in the svgcairo case).  However, our
> svgcairo device does not work nearly as well as our pscairo, pdfcairo,
> pngcairo, and xcairo devices. For svgcairo, all the plot lines and shapes
> are there in the resulting SVG file, but the text annotations are missing!
> 
> Therefore, is PLplot wasting its time using
> cairo_svg_surface_create_for_stream to implement an SVG device as a simple
> add-on device to our other cairo-related devices, do we have to do more than
> a simple call to cairo_svg_surface_create_for_stream to get text to work, or
> can we eventually expect text rendering to work automatically for this
> device like it does for the rest?
> 
> Alan
> __________________________
> Alan W. Irwin
> 
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
> 
> Programming affiliations with the FreeEOS equation-of-state implementation
> for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
> package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
> Linux Links project (loll.sf.net); and the Linux Brochure Project
> (lbproject.sf.net).
> __________________________
> 
> Linux-powered Science
> __________________________
-- 
behdad
http://behdad.org/

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