I committed a slightly tighter version of this that uses a rectangle based on the size of the image plus a border to accomodate the exact marker size. Probably makes very little difference, but I suppose if there was a dense field of markers outside of view, this might speed things up a bit more.
A further optimization might be to use the clipping rectangle, but that's not necessary merely to prevent the segfault. Mike On 09/24/2009 12:06 AM, John Hunter wrote: > On Wed, Sep 23, 2009 at 10:15 PM, John Hunter<jdh2...@gmail.com> wrote: > >> On Wed, Sep 23, 2009 at 6:47 PM, Mike Nicolls<michael.nico...@sri.com> >> wrote: >> >>> I've encountered a segmentation fault using the Agg backend when making >>> and saving a png plot. The segmentation fault does not seem to occur >>> under different backends (e.g. Cairo). >>> >>> The sequence of commands amounts to making a plot, setting the limits of >>> the plot, then saving the plot as a png using savefig. If the value of >>> one of the points is too large, a segmentation fault is generated. >>> Obviously the simple work-around is to not plot the out-of-bounds >>> points, but the segmentation fault is probably not the desired behavior! >>> >>> Below is an example, which generates a segmentation fault on matplotlib >>> versions 0.99.0 (run on OS X 10.5.8) and 0.98.5.2 (run on Fedora 11 and >>> CentOS 5.3). >>> >>> Can others reproduce this issue? >>> >> Thanks for the report -- I can confirm this on OSX and linux on svn HEAD >> >> I've made minor tweaks to your test case to make it deterministic:: >> > I applied the following patch to the branch and head -- it feels like there > would be a more elegant way to handle it, so I'd like Michael at least to > take a look at it:: > > home:~/mpl> svn diff -rPREV:HEAD src/_backend_agg.cpp > Index: src/_backend_agg.cpp > =================================================================== > --- src/_backend_agg.cpp (revision 7820) > +++ src/_backend_agg.cpp (revision 7821) > @@ -608,6 +608,14 @@ > > x = (double)(int)x; y = (double)(int)y; > > + // if x or y is close to the width or height, the filled > + // region could be inside the boundary even if the center is > + // out. But at some point we need to cull these points > + // because they can create segfaults of they overflow; eg > + // > https://sourceforge.net/tracker/?func=detail&aid=2865490&group_id=80706&atid=560720 > + if (fabs(x)>(2*width)) continue; > + if (fabs(y)>(2*height)) continue; > + > pixfmt_amask_type pfa(pixFmt, alphaMask); > amask_ren_type r(pfa); > amask_aa_renderer_type ren(r); > @@ -629,6 +637,14 @@ > > x = (double)(int)x; y = (double)(int)y; > > + // if x or y is close to the width or height, the filled > + // region could be inside the boundary even if the center is > + // out. But at some point we need to cull these points > + // because they can create segfaults of they overflow; eg > + // > https://sourceforge.net/tracker/?func=detail&aid=2865490&group_id=80706&atid=560720 > + if (fabs(x)>(2*width)) continue; > + if (fabs(y)>(2*height)) continue; > + > if (face.first) { > rendererAA.color(face.second); > sa.init(fillCache, fillSize, x, y); > > ------------------------------------------------------------------------------ > Come build with us! The BlackBerry® Developer Conference in SF, CA > is the only developer event you need to attend this year. Jumpstart your > developing skills, take BlackBerry mobile applications to market and stay > ahead of the curve. Join us from November 9-12, 2009. Register now! > http://p.sf.net/sfu/devconf > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
