Re: Ggnuplot-beta@lists.sourceforge.netnuplot crashing =?iso-8859-1?q?for=09?="hidden3d undefined" ?

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

On Sunday 28 October 2007 15:11, Hans-Bernhard Br=F6ker wrote:
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> Mouse interaction doesn't really have much to do with this --- or=20
> rather, it shouldn't.

Maybe I mis-understood the original bug report, but certainly the=20
problems that I have observed myself are directly due to mouse
interaction.  What happens, as Thomas described a moment ago, is that
if you use the middle mouse button to zoom in the vertical, then the
program dies on an assert test just before the plotted surface
reaches the edge of the plot area.  There is no particular reason that
the program could not continue to zoom further; it would just have to
clip to the top boundary of the plot.   And that is exactly what
version 4.0 does.  The 1.53 -> 1.54 patch was the exact change that
broke this.

Actual segfaults or mis-tracking of the vertices doesn't happen
unless/until there is more extreme abuse of the scaling parameters.

Trials to replace the assert() statements with int_warn() return the
behaviour to that of 4.0, which is much more user friendly.
If you try really hard, you can make the program crash.  But the way
it is now, it crashes whenever you expand the plot even an infinitesimally
beyond the plot border. This can easily happen while mousing, and
it's quite annoying.

I am thinking that the assert tests are looking at the wrong thing.
As I read it, they will trigger as soon as the vertical extent of the
plot hits 1.0  in screen coordinates.  Why?  Most of the terminals can
do proper clipping.  Certainly x11 and wxt seem to clip properly if I
remove the assert statements.  Do you recall which terminal was causing
problems when you first put them in?

	EAM



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> The key problem are the third and fourth parameter to 'set view', and=20
> how they affect the plot.  From the start these parameters were the=20
> wrong approach to the perceived problem of incomplete space utilization=20
> by 3D plots.  They cause the plot to outside all sensible boundaries ---=
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> the graph box, the viewport, and eventually even the page itself.
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> surface_zscale (the fourth argument of 'set view') is the worst of them.=
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>   The only effect this parameter reliably has is to blow the plot off=20
> the page.
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> > that's why i think that the y-min/max-values should be checked
> > against some combination of 'surface_scale' and 'surface_zscale'.
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> I think both of these variables should be killed for good.
>=20
>=20
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=2D-=20
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742