Introduction

Size of RoundedRectangular for art design would be (13/16) of 1024X1024 equal 832X832 CornerRadius of RoundedRectangular would be (22/100) of 832.0 or in other word would be (22/100)X(13/16)X1024.0

References

1. Human Interface Guidelines/App Icons and images
2. Apple Design Resources
3. Why is my app icon bigger than the others in the macOS dock?
4. Apple Icons