[Octave-bug-tracker] [bug #53753] Animation performance jumpy

[Marshall]

URL:
  <http://savannah.gnu.org/bugs/?53753>

                 Summary: Animation performance jumpy
                 Project: GNU Octave
            Submitted by: marsian
            Submitted on: Wed 25 Apr 2018 04:49:18 PM UTC
                Category: Plotting
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: Marsian
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.3.91
        Operating System: Microsoft Windows

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Details:

In animating some plots I found that the performance in 4.3.91 was rather
jumpy. It seemed to skip frames whereas other versions didn't. Maybe drawnow
is not working properly? I tried the following in three versions of Octave
(even simultaneously for side-by-side comparison without the if statement):


close all
figure(1)
x = 0:0.01:4*pi;
y = sin(x);
p = plot(x,y);
xlim(x([1,end]))
v = ver;
title(v(1).Version)
i = 0;
tic;
while 1
    i+=0.01;
    set(p,'ydata',sin(x+i));
    drawnow;
    %remove this 'if' for continuous animation
    if toc>5
        disp(i);
        break;
    endif
endwhile


The versions I used were:  
4.3.91 (hg id: ff59be58f028)
4.5.0+ (hg id: 55480087f125)
4.2.2

I found that 4.2.2 and 4.5.0+ ran smoothly, though 4.5.0 was significantly
faster. 4.3.91 seemed to skip frames (and appeared to run slowly because of
it). The following speed printouts resulted: 4.2.2 printed  5.1600, 4.5.0+
printed  33.460, and 4.3.91 printed 46.720. So 4.3.91 was technically faster,
but seemed slowest because of the jumpiness because every frame wasn't shown.




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