Using a path e.g. graphics.arc as a mask?

[Aaron McGuire]

Is it possible to use a "stroke" as a mask? 

[ivan.popelyshev]

Only in Webgl mode. No fallback in canvas.

[grelf]

You can indeed use a stroke path for clipping in the ordinary 2D context. See https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/clip

And I say more about it on my Forest design page: see https://grelf.net/forestdesign.html#N657302

[ivan.popelyshev]

ctx.beginPath();
ctx.arc(100, 75, 50, 0, Math.PI * 2);
ctx.clip();

@grelf its fill. 

Unless author of the topic also thinks that stroke and fill is the same thing ...