Fabric.js cannot have the background of a canvas transparent

Question

I would like to have the canvas (see image) to have a background (around the gabarit) to look like this:

I have tested to save the canvas with background color set to null and background image set to null, but it's always white.

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Answer 1

You can set the canvas background to transparent like this:

canvas.set('backgroundColor', 'transparent').requestRenderAll();