#1492 arrowheads for vectors drawn in hidden3d mode

[Tatsuro MATSUOKA]

In Japanese BBS for gnuplot, there reported that arrow mark of vector was disappeared with setting hidden3d. It was reported the phenomenon occurred on gnuplot 4.6.

I have checked on gnuplot 4.4.4, 4.6.5, 5.1(cvs) (windows) and 4.6.5 (Ubuntu).

The script that reproduce the issue (modifed from the original post by me.)

==================================================

reset
set term pngcairo

set xrange [0:0.6]
set yrange [0:0.6]

set output 'unset_hidden3d.png'
splot \ '-' u 1:2:3:4:5:6 w vec title'arrow', \ '-' u 1:2:3:4:5:6 w vec nohead title'segment'
0 0 0 0.5 0.2 0.3
e
0.1 0 0 0.5 0.4 0.6
e
set output

set hidden3d
set output 'set_hidden3d.png'
splot \ '-' u 1:2:3:4:5:6 w vec title'arrow', \ '-' u 1:2:3:4:5:6 w vec nohead title'segment'
0 0 0 0.5 0.2 0.3
e
0.1 0 0 0.5 0.4 0.6
e
set output

==================================================

[Tatsuro MATSUOKA]

I attached the second plot (with setting hidden3d)

[Tatsuro MATSUOKA]

Is the behavior the side effect hidden3d or feature of gnuplot?

[Ethan Merritt]

So far as I know, the code in hidden3d,c has never tracked arrowheads, and the code in do_arrow() has never allowed for hidden3d. So both sets of routines would have to be re-written.

[Tatsuro MATSUOKA]

Thank you for the explanation. I understand the situation and will report it in the Japanese BBS for gnuplot.

[Ethan Merritt]

Ticket moved from /p/gnuplot/bugs/1478/

[Ethan Merritt]

I am sorry for providing wrong information.
The hidden3d code does try to handle arrowheads.

So maybe this really is a bug.
I will return it to the bug tracker.

One bug in hidden3d with vectors has been fixed last week.
This seems to be a different bug.

In version 5 I see the opposite problem:
In the "unset hidden3d" plot both lines are drawn correctly.
In the "set hidden3d" plot both lines have arrowheads.

[Ethan Merritt]

Ticket moved from /p/gnuplot/feature-requests/405/

[Ethan Merritt]

Now fixed in CVS for both 5.0 and 5.1

[Tatsuro MATSUOKA]

I have confirmed the fix. However, set hidden3d, color of second line (segment, light blue) is different from that in unset hidden3d (segment, light green). Is this intentional?

[Ethan Merritt]

I doubt it.
I guess the reason is that the hidden3d code reserves two colors for each plot. For a surface plot one color is used for the front and the other color is used for the back.

Confirmed. The program always increments the linetype by 2 when hidden3d is active, whether or not the plot actually uses 2 colors. This is true for all plot types except pm3d and images.