Tong Mu 5e42c80fb4
Add RoundedSuperellipseBorder and apply it to CupertinoActionSheet (#166303)
This PR creates a new class `RoundedSuperellipseBorder`, which is the
main way to draw a rounded superellipse with filling and/or stroking.

The new class is very similar to `RoundedRectangleBorder` and shares a
lot of private code, therefore they reside in the same file.

For demonstration purposes, the rounded superellipse is also applied to
`CupertinoActionSheet`, whose cancel button was drawn with the border
class.



https://github.com/user-attachments/assets/39599dcf-5cf1-46e1-ab34-8c477cbef9d4

(Sadly this demo wouldn't fit for dartpad because rounded superellipses
are not yet supported on Web.)

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above.
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2025-04-08 00:05:23 +00:00
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