Re: pm3d and parametric function surface plots

[Petr M. <mi...@ph...>]

> > (*) Quadrangles may take a lot of memory. I propose to change double to
> > float (should probably happen also for gpdPoint structure).
> >
> > typedef struct {
> >     double gray;
> >     double z; /* maximal z value after rotation to graph coordinate system
> > */
> >     gpdPoint corners[4];
> >     gpiPoint icorners[4]; /* also if EXTENDED_COLOR_SPECS is not defined */
> > } quadrangle;
>
> Please, if you do that, respect prior art and use the existing type
> 'coordval' for that.  That's what this type was designed for: it's
> defined as double on platforms that can afford it, and float elsewhere.

IMHO, gnuplot is using too much memory for images and surfaces -- or, in
other words, it can work with large images, like >=512^2 pts, but it
suffers. I would prefer not to use double if float is sufficient, as in this
case.

The above structure is 64 B for double, and 40 B for float.
For an image of 512^2 it would save 6 MB.

Well, we can always recompile gnuplot for using float instead of double. I
do sometimes.

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PM