A tiny (< 100 LoC) library for trimming whitespace from a canvas element with no dependencies.

npm i -S trim-canvas

import trimCanvas from 'trim-canvas'

const canvas = document.createElement('canvas')

// do some drawing on it ...

trimCanvas(canvas)
// now the whitespace has been trimmed

If you don't want to mess with your existing canvas, then simply clone the canvas element beforehand.

trim-canvas returns the canvas element for easy chaining.

Can see how trim-canvas is used inside of react-signature-canvas here. It includes a step for cloning the canvas.

You can see a demo of trim-canvas here.

(N.B. this is the demo for react-signature-canvas which depends on trim-canvas)

Credits go to @efc for writing a quick version of this in this issue and to the original StackOverflow Answer that was credited in that issue.