Re: Missing colorbox with pm3d points plot

[Ethan A M. <merritt@u.washington.edu>]

On Thursday 21 September 2006 02:12 pm, Hans-Bernhard Br=F6ker wrote:
> Joe Koski wrote:
> > I asked about this problem on the gnuplot help list and didn't get a
> > response after a day or two, so I am assuming that it is a bug, not a n=
ew
> > feature. Attached in .tar.gz format is a script and a short data file t=
hat
> > reproduce the bug on my machine.
>=20
> The example is a bit too complicated.  It can be boiled down to just one=
=20
> command:
>=20
>     splot x+y with points palette
>=20
> The outermost reason why this plot doesn't get a colorbox is that the=20
> comparison against TC_DEFAULT made by set_plot_with_palette is=20
> triggered.  The plot in question has a pm3d_color.type value of 6, as if=
=20
> the user had specified 'palette z'.  This might be an inadvertant side=20
> effect of the changes that allowed 'with points palette cb -45' etc.

I think that is correct.
As best as I can make out, the error arises from a false assumption that was
waiting to bite us for a long time.  I don't know exactly which change
caused it to emerge.  The offending lines are these, from pm3d.c

1001       if (this_3dplot->lp_properties.use_palette) {
1002           if (this_3dplot->lp_properties.pm3d_color.type !=3D TC_DEFAU=
LT)
1003               /* can this really happen? for which syntax? */
1004               want_palette_but_not_colorbox =3D TRUE;
1005               /* don't return yet -- decide later whether showing colo=
r box is desirable */

The implicit assumption is that no color spec other than TC_DEFAULT uses
the palette. This has been incorrect for a very long time, but was not a
problem until you could explicitly override the default color-by-z style
of splot surfaces using another palette option. =20

The fix is

=2D-- gnuplot/src/pm3d.c	2006-06-15 08:42:33.000000000 -0700
+++ gnuplot-cvs/src/pm3d.c	2006-09-22 21:25:10.000000000 -0700
@@ -999,8 +999,8 @@
 		return;
 #endif
 	    if (this_3dplot->lp_properties.use_palette) {
=2D		if (this_3dplot->lp_properties.pm3d_color.type !=3D TC_DEFAULT)
=2D		    /* can this really happen? for which syntax? */
+	        int type =3D this_3dplot->lp_properties.pm3d_color.type;
+		if (type =3D=3D TC_LT || type =3D=3D TC_LINESTYLE || type =3D=3D TC_RGB)
 		    want_palette_but_not_colorbox =3D TRUE;
 		    /* don't return yet -- decide later whether showing color box is des=
irable */
 		else


=2D-=20
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742