Eric Firing wrote: > Michael Droettboom wrote: >> This is a very good test to have -- we should add it to >> backend_driver.py. >> >> FWIW, SVG appears to behave similarly to PDF, and has a "miter-limit" >> property to control when to bevel vs. miter when the mode is set to >> "miter". (Though the default threshold appears to be different.) I >> didn't look into Ps, but it may have a similar configuration. >> >> Agg also has a miter limit (which is not currently settable from >> Python), but it reverts to what it calls "smart" beveling, rather >> than regular beveling when below that limit. It does, however, have >> another miter mode called "miter_join_revert" which doesn't do smart >> beveling. (Try the "conv_stroke" example in the Agg source). In >> fact, it has this comment associated with it (agg_math_stroke.h:275): >> >> // For the compatibility with SVG, PDF, etc, >> // we use a simple bevel join instead of >> // "smart" bevel >> >> I think there is an argument to be made that we should use this mode >> instead in the Agg backend, to be consistent with PDF and SVG (see >> patch below). >> >> On a higher level, however, I am a bit concerned about this miter >> limit concept. It seems a bit dangerous for scientific plots: there >> is a large change in the look of the corner after only a small change >> in angle around the miter limit threshold. It may make the data >> appear to have large changes where in fact the changes are small. >> This seems like an argument of "bevel" or "round" as the default line >> join (it is currently "miter"). I also like the idea of "round" join >> keeping the corner close to the actual data point. >> >> Now, if the user wants miter joins, they can, but I would suggest >> that we set the miter-limit threshold in all backends high enough >> such that it "always miters" and "never bevels". I can't see why >> (for other than artistic purposes), one would want to sometimes miter >> or bevel depending on angle in a scientific plot. We can expose >> miter limit as a parameter somehow, but for a default, I think it >> should be "always miter". What do you think? > > Everything you said above sounds right to me, for plotting data--round > joins are likely to provide a good combination of aesthetics and > faithfulness to the data. Miters are needed for things like arrows > (e.g. in quiver), and pcolor patches. >
Good "point" (pun intended). If we change the default from miter, we will need to ensure that arrows etc. are explicitly asking for miter joins. Cheers, Mike ------------------------------------------------------------------------------ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
