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Dan
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Changing xlim & ylim of axes sluggish

Asked by Dan
on 18 Dec 2013
Latest activity Commented on by Dan
on 20 Dec 2013
I implemented my own pan & zoom functionality which adjusts the xlim & ylim of an axes as the user moves the mouse. Although this works OK, it's a bit sluggish & "laggy". I'm guessing that the data coming from the mouse is overwhelming the systems ability to change the axes properties.
Does this sound reasonable? If so, does the axes have a "busy updating" flag I can test? Or is there some other explanation?
Any ideas?
TIA
Dan

  3 Comments

How much data have you plotted?
A lot! ;-) I neglected to mention that the axes contains an image.
That might the source of your problem. The image is re-plotted every time you refresh your axes. Please try with fewer data to see if that's the problem.

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2 Answers

Answer by David Sanchez
on 18 Dec 2013

You have too many processes trying to run at the same time. Even when it sounds incoherent, insert a very short pause right after reading the mouse position
pause(0.0001);
That will refresh the buffer ( or something like that ) and the graphics will be plotted less "laggy".

  1 Comment

I think we are both close to the answer.... but not quite there. I'm actually doing this inside GUIDE so I'm not certain where to put this pause. I tried putting it on the first line inside the function that gets triggered when the mouse moves (WindowButtonMotionFcn) but it didn't seem to do much. In fact.... it almost feels like this would make things worse but I'm not certain. Maybe I need a careful insertion of "drawnow"? This is tricky.

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Answer by Kelly Kearney
on 20 Dec 2013

Not sure if this is exactly the effect you're going for, but for panning around an image via mouse movement, I've found this function: zoom2cursor to be very well-done, and I've used that code as a template to pan around some very large images without any noticeable latency.

  1 Comment

Thanks for the info on zoom2cursor. I'm both pleased and disappointed that the function seems to have similar laggy/jerky behavior. (Pleased because Brett knows his stuff so I'm doing something right). So... I'm thinking it's perhaps either my computer or perhaps I need to play with the "interruptible" and/or "busy action" properties of the axes.
Thanks again
Dan

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