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Canvas problems in 3.2.7


I have written some classes for opensesame that use the canvas class to draw scales or progress bars, these work in versions 2.9 and 3.1 but no longer work in 3.2.7 (and 3.2.5), did try 3.2.1 and 2 but these failed on canvas.text_size().

There are two issues:

1) No progress bar is shown, unless you add a check for a keyboard event after each show(), only in legacy.

2) If text (percentage of progress)is shown then the time to draw takes 40+ms longer.

Time to draw 0 to 100% incrementally , under same conditions, average time in milliseconds

Whats also interesting is that the time to draw in psychopy increases significantly in 3.2.7

I am testing this on an i7 computer with WIndows 7 64bit installed. I am using the none install versions of opensesame.

Do you have any ideas?



  • Hi Gary,

    The Canvas API has been reworked for OpenSesame 3.2. However, all changes should be fully backwards-compatible, at least as long as you don't use any hacks that go beyond the documented API. (Are you?) Regarding performance: as of 3.2, text is rendered using a web engine. This is much better in almost every way. However, it's also a bit slower, or at least it can be, depending on the specifics.

    So, in general, the things that you're reporting here aren't that surprising. However, without seeing the actual code I cannot say much more about it, or suggest ways to improve the performance of the code (which is probably possible)!



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

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