#2788 splot: black box around 3d plot in side-on viewing angle

[Anonymous]

When doing a 3d plot using thesplot command and rotating the plot to a view along the x-axis, the plot has a black box around it, if the view is exactly 90,0. The black box disappears if the view is 90,360 however.

Version of gnuplot: 6.0.2 (Present sice 6.0.0), qt terminal (also happens in x11 terminal)
OS: Linux Mint 22.1, Linux Kernel 6.8.0-57-generic
Steps to reproduce:
- Open gnuplot in a terminal
- Define any function dependent on 2 variables, e.g. f(x,y)=x*x+y
- set view 90,0
- splot f(x,y)
- The black box should now appear
- set view 90,360
- replot
- The black box should now have disappeared

[Ethan Merritt]

Pure axial projection of a 3D plot are treated as 2D plots, complete with the normal border drawn around it. You are seeing this border, just as you would if you had created the plot with plot rather than splot. You could turn it off with unset border, but then the partial bounding box lines would also not be drawn in the general 3D view angle case.