search

rtoy / maxima

A Clone of Maxima's repo
Other
0 stars 0 forks source link

Glitch in plot #4052

Open rtoy opened 2 months ago

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 10:46:58 Created by macrakis on 2021-04-20 21:55:23 Original: https://sourceforge.net/p/maxima/bugs/3775

There is a weird glitch to the right of (0,1) and to the left of (0,-1) in plot2d(signum(x),[x,-1,1],[y,-1.1,1.1])

This only appears with the wxt terminal of gnuplot, but not x11 or Tk8.6's canvas widget (used in Xmaxima) -- reported as https://sourceforge.net/p/gnuplot/bugs/2438/, possibly in the wxWidgets library.

Maxima 5.44.0 SBCL 2.0.0 Windows 10 gnuplot 5.2/PL8

Attachments:

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 10:46:59 Created by macrakis on 2021-04-21 21:27:03 Original: https://sourceforge.net/p/maxima/bugs/3775/#524b

This seems to be a gnuplot bug, which seems to happen when plotted points are "too close" together (as happens near a discontinuity using adaptive plotting). I have reported it as https://sourceforge.net/p/gnuplot/bugs/2438/

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 10:47:03 Created by macrakis on 2021-04-23 02:58:51 Original: https://sourceforge.net/p/maxima/bugs/3775/#8d8c

On the corresponding gnuplot bug, Ethan Merritt diagnosed this as being a problem in recent pango/cairo libraries, and suggested changing the anti-aliasing settings. Some experimentation with the wrench/rendering method menu shows that the best setting is just antialiasing without oversample.

Fortunately, that setting is persistent across gnuplot sessions... though it would be even better if we could preset it for the wxt terminal at Maxima installation time.