Re: flickering "allocating colors ..." message

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

On 04/18/2011 05:50 AM, albert_a wrote:
>
> Hi All, I have experienced a problem on Octave painting dynamic signal in
> graphics window using plot(..) function.
> Octave uses Gnuplot as a back-end.
> Everything is fine except the window caption.
> Two titles compete all the time "Figure 1" and "Figure 1: allocating colors
> ...".
> This makes very irritating flickering effect.

I'm guessing that you are using Octave in a "real-time" fashion to 
monitor some data signal, i.e., refreshing the plot often.  Is this right?

The reason for the note about "allocating colors" was that for large 
palettes the color map could take a while to create and one might be 
left wondering what gnuplot was doing.  On the other hand, there has 
been a lot of development with palettes and it may be the case now that 
doesn't take so long.  I do recall writing some things that refresh 
palettes, etc. only when necessary.  Perhaps we should review that with 
some demos to see what the behavior of "allocating colors..." is like. 
If for large palettes it only is present for a fraction of a second or 
to a couple seconds, it makes no sense in having it.


> The problem resides in the file 'gplt_x11.c' line 3563 in the Gnuplot
> source.
> I have commented out the code that produces "allocating colors ..." message
> and recompiled Gnuplot.
> My appeal: Could Gnuplot developers find a better workaround to this
> problem.

Consider yourself a low ranking developer, I guess.  People can submit 
patches to the gnuplot SourceForge project.  But let's talk about the 
options:

1)  Get rid of the note about "allocating colors..." if it is no longer 
necessary.  (And search for any other similar notes...of which I doubt 
there are any.)

2)  If the palette is large (above 2048?) then indicate "allocating 
colors...", otherwise do not.

3)  If the user specifies a window title for the x11 plot, then do not 
append "allocating colors..." in any case.

Tell us something about your application Albert.  Are you working with a 
small enough palette that there is little delay between refresh, such 
that 2 above would solve things?  I think Octave has (or should have at 
this point) the ability to control the window title now.

Dan