How to make a conical gradient in iOS using Core Graphics / Quartz 2D?

Question

How can I draw such a conical gradient in iOS using Core Graphics / Quartz 2D API?

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Answer 1

There is no Quartz function for this style of gradient. Unless you're ready to dig into mathematics behind it, I'd suggest you use pre-made images for this. It's not a problem if you need it only for opacity mask.