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canvas question

Hey guys,
I need some ideas on how to implement something that seems easy but yet eludes me. Basically, I want to show a map and when people click on a location to save its pixel coordinates. I've done the click and save part by recycling some code from another example and drawing a fixation point on the mouse location on the canvas (see attachment). The problem is that when I add the png for the map in the while loop that controls the mouse, things slow down a lot. This is of course to be expected as the png gets redrawn on the canvas all the time, but how should I do this instead? Basically, I want to display the map once and redraw the mouse continuously. I tried putting the map outside of the loop but I haven't manged to make the mouse update as it should. Any ideas?
Thanks in advance,


  • sebastiaansebastiaan Posts: 2,701

    Hi Marios,

    First thought: Why don't you simply let the operating system draw the mouse cursor?


    That way you don't have to redraw the canvas over and over again. But if, for whatever reason, that is not an option, there are a few other things you could try to improve performance:

    • Set the timeout to 0, instead of 20
    • Change the backend to legacy, which is faster when it comes to stimulus rendering


    Thanked by 1mariosav

    There's much bigger issues in the world, I know. But I first have to take care of the world I know.

  • mariosavmariosav Posts: 29

    Thanks Sebastiaan! Initially I was thinking of doing mouse tracking so I went down this route. But, if I decide against it then I could just have the os draw the mouse. Good point. I'll also try the other things you suggested and see what happens. :)

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