Notes

In this lesson, we implement two classes:

• TaskCompletionRing as a StatelessWidget
• RingPainter as a CustomPainter

When implementing a CustomPainter, we need to override the paint() and shouldRepaint() methods.

The paint() method has two arguments:

• a canvas object that we can use to draw things
• a size object that tells us how big is the drawing area

shouldRepaint() should return true when something has changed.

We can use an AspectRatio to enforce a certain proportion of width to height (in this case: 1.0).

Here's a full tutorial on how to use CustomPainter:

• Flutter Custom Painting: Do Not Fear The Canvas