Re: maximing/resizing multiple x11: change of palette

[Daniel J S. <dan...@ie...>]

Daniel J Sebald wrote:

> I've tried some images in Octave, increasing the palette 2^6, 2^7, 
> etc. Around 2^14 gnuplot_x11 *really* slows down.  I'm talking on the 
> scale of minutes.
>
> Could it be that:
>
>          if (XAllocColor(dpy, new_cmap->colormap, &xcolor)) {
>
> is a slow routine and allocating these colors one at a time is very 
> slow?  Is there some way to assign colors all at once?


Actually, that may not be the problem.  I notice that choosing the max 
colors in gnuplot to be 32768 doesn't take too long.  So the difference 
may be that in Octave the palette is custom and the issue is all the 
ASCII encoded palette information going across the gnuplot/gnuplot_x11 
pipe and then read using scanf.  (I'm not sure.)  This could be a little 
annoying when working in Octave, although I don't think images often 
have a resolution much beyond 12 bits.

However, I would say that if it does turn out to be a problem, once the 
colormap is put in X, the window refreshes just fine... so I'm wondering 
if *not* always sending the palette information to gnuplot_x11 would be 
a good thing to do.  I don't see a problem with sending the palette only 
when it should be changed.  I'll put a toe in that camp for now.

Dan