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canvas-autoscale experimental

A variant of canvas-fit that handles some extra magic for you: adjusting the scale of the canvas to maintain smooth framerates.

As of version 2.x.x, the approach for scaling has changed slightly to make it more predictable.



resize = autoscale(canvas, [options], [updated])

Returns a resize function you can use to update the size of the canvas to fit within its parent element. Takes the following options:

  • parent: the parent element to fit within. Defaults to the canvas' parent element.
  • scales: an array of scales to attempt. Defaults to [0.25, 0.5, 1, devicePixelRatio].
  • target: a two-element array containing the target framerates – the first element is the maximum rate before reducing scale, and the second is the minimum before increasing it again. Defaults to [55, 59].
  • fps: a custom function that should return the current framerate. Optional.
  • gap: the amount of frames to wait between rescales. Defaults to 60.
  • auto: automatically resize/rescale the canvas in response to window resizes and framerate changes respectively. Defaults to true, set to false to disable.
  • sensitivity: the amount of sensitivity for canvas rescales. Set to 0 to ignore rescales, and 1 to make them immediate. It's recommended you choose a figure around 0.01, which is the default.

updated is called every time the canvas size is changed – pass your render function in here to avoid the screen flickering every time your canvas is resized.


If you're using auto: false, call this method once per frame to check the canvas' framerate and update the scale accordingly.


Read-only property to get the current scale of the canvas.


The most recent framerate captured.


Manually trigger a resize of the canvas. Useful, for example, when resizing the screen.


MIT. See for details.