[IPython-dev] Qt SVG clipping bug (it's NOT a matplotlib bug)- Qt won't fix...

Michael Droettboom mdroe at stsci.edu
Thu Oct 14 11:27:10 EDT 2010

On 10/14/2010 10:52 AM, Robert Kern wrote:
> On 10/14/10 3:55 AM, Hans Meine wrote:
>> PS: Here are the current docs; I could not find a word about clipping in them:
>>     http://doc.qt.nokia.com/4.7/qtsvg.html
>>     http://doc.qt.nokia.com/4.7/qsvggenerator.html
> They have removed some information from their documentation in recent versions.
> As of 4.5, they are only claiming to support the static features of SVG 1.2 Tiny
> in both the rendering and generation:
>     http://doc.qt.nokia.com/4.5/qtsvg.html
> SVG 1.2 Tiny does not support clipping.
>     http://www.w3.org/TR/SVGMobile12/
> That's why the bug reports have been closed as "won't fix". They are out of
> scope for the standards they have decided to support.
> It might be worthwhile for matplotlib to only use the SVG 1.2 Tiny standard for
> greater compatibility. Tiny is much easier to implement, so I suspect there are
> now more Tiny renderers now than there are Full renderers.
This is true -- and we can probably remove some of the simpler-to-remove 
parts that are missing from SVG Tiny.  However, to support clipping, we 
either have to either a) write the routines to do clipping in vector 
space or b) use rasterized fallbacks (as we do for some alpha issues in 
Postscript, for instance).  a) is non-trivial in the general case, 
particularly when accounting for line thicknesses, and b) is a hack.


Michael Droettboom
Science Software Branch
Space Telescope Science Institute
Baltimore, Maryland, USA

More information about the IPython-dev mailing list