`notMultiplied` for `useContextAlpha` renderer option missing in the docs

‘By accident’ I bumped into an example that turns of pre-multiply from the renderer (transparent: 'notMultiplied'), so I was wondering what else is possible to set the transparent option of the renderer to.

I couldn’t find the option in the docs, so looked in the code. To find out the useContextAlpha seem to do the same thing, so looks like an alias.

useContextAlpha is in fact mentioned in the docs. However it tells us nothing about a 'notMultiplied' value and only tells us to not fiddle around with the setting.

IMO the 'notMultiplied' option is an important option to know for people understanding the difference between straight and pre-multiplied and should at least be mentioned there in the docs as a possible value to put in there. According to the docs the option accepts only boolean values, but obviously this particular string is accepted too. It might be me, but it looks like this option is ONLY useful to use with the notMultiplied value in it, as when setting useContextAlpha to false it looks like the same thing as setting the backgroundAlpha to 0, which would make the option obsolete IMO. But I didn’t deep dive in the code, so I might be missing something here.

IMO the notMultiplied option should be mentioned in the docs.

• pixi.js version: 6.2.1

[bigtimebuddy]

Doc changes for v6 are fine! PR still welcome here

[ryushar]

Pass-through setting for the the canvas’ context alpha property. Passing ‘notMultiplied’ will set the canvas’ context alpha property to true and premultipliedAlpha to false. This is typically not something you need to fiddle with. If you want transparency, use backgroundAlpha.

If this definition is fine then I can make a PR for it