[Octave-bug-tracker] [bug #34523] surf() with gnuplot does not handle FaceColor correctly

[Dan Sebald]

Follow-up Comment #12, bug #34523 (project octave):

gnuplot documentation indicates the 'linetype' feature appeared in 4.6, so I
added that to the gnuplot-has-feature code and made a very small change to the
gnuplot_linetype function--basically adding another condition to an
if-elseif-else statement.

I've looked into the hidden line removal and there is quasi-support for such a
thing with the "pm3d" surface.  Using the command

set hidden3d front

will plot the surface first, and then everything else on top of that.  Then if
all the lines are using the hidden3d algorithm, it does look like proper
hidden3d surface (provided the surface doesn't have any overlapping
elements).

Unfortunately, I think there is a bug in the color operation for lines under
the hidden3d mode.  I will let you experiment, and then we can decide to
either put the "set hidden3d front" statement in the gnuplot stream, have a
bad plot and wait for gnuplot to catch up...or wait for gnuplot to be fixed
and then come back to revisit the hidden3d line removal.

To experiment, generate the test surface plot as before.  Then use the Octave
command:

drawnow ("qt", "/dev/null", false, "foo1.gp");

(The terminal can be "x11" if you wish, and in fact it produces different
behavior so you may want to test that as well.)  Next, edit the file 'foo1.gp'
and place after the "unset hidden3d" line "set hidden3d front;", i.e.,

unset hidden3d
set hidden3d front;

Launch gnuplot and enter "load 'foo1.gp'".  On my system, the surface lines
are missing (qt) or appear white (x11).



(file #34301)
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Additional Item Attachment:

File name: octave-gnuplot_surf_facecolor-djs2015jun23.patch Size:10 KB


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