How to create a single gobjects for different plots to avoid using clf

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I'm trying to use plot() several times without using clf because this causing my animation to blink. In the discussion in here [plot is blinking when clearing figure], a clever solution suggested by @Walter Roberson is to update data rather than creating a new object for plot every iteration. I've managed to create the following minimal working example as a start point for my problem. For each function (i.e. y1,y2), I need to create a new gobjects so that I can update their data rather than calling clf which causes terrible. The problem with the aforementioned approach is the fact that I need to create gobjects for each drawable thing. In my actual application, drawable things are unknown a priori. In the simuation, I have to add them depending on specific conditions. My question is how can I modify the below code in a clever way to use a shared gobjects and at the same time avoid using clf.
objarray = gobjects(1,2);
x=0:0.1:1;
y1=sin(x);
y2=cos(x);
for i=1:20
if ~ishghandle(objarray(1))
objarray(1) = plot(x,y1,'LineWidth',2);
else
x=0:.1:i;
y1=sin(x);
objarray(1).XData = x;
objarray(1).YData = y1;
end
if ~ishghandle(objarray(2))
if ~ishold
hold on
end
objarray(2) = plot(x,y2,'r','LineWidth',2);
else
x=0:.1:i;
y2=cos(x);
objarray(2).XData = x;
objarray(2).YData = y2;
end
axis([0 22 -2 2])
pause(.2)
end
The above code can be done with clf as follows which is not working for my case.
for i=1:20
clf
x=0:0.1:i;
y1=sin(x);
y2=cos(x);
plot(x,y1,'LineWidth',2);
hold on
plot(x,y2,'r','LineWidth',2);
hold off
axis([0 22 -2 2])
pause(.2)
end

Answers (1)

darova
darova on 9 Aug 2021
Try this way
x = 0:.2:10;
y1 = x + nan;
y2 = x + nan;
h1 = plot(x,y1,'r');
h2 = line(x,y2);
for i = 1:length(x)
y1(i) = sin(x(i));
y2(i) = cos(x(i));
set(h1,'ydata',y1);
set(h2,'ydata',y2);
pause(0.1)
end

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