How to safely floor or ceil a CGFloat to int?

Question

I often need to floor or ceil a CGFloat to an int, for calculation of an array index.

The problem I permanently see with floorf(theCGFloa

Answer 1

Swift supplemental answer

I am adding this as a supplemental answer for those who come here looking how to use floor and ceil with a CGFloat (like I did).

var myCGFloat: CGFloat = 3.001
floor(myCGFloat) // 3.0
ceil(myCGFloat) // 4.0

And if an Int is needed, then it can be cast to one.

var myCGFloat: CGFloat = 3.001
Int(floor(myCGFloat)) // 3
Int(ceil(myCGFloat)) // 4

Update

There is no need to use the C floor and ceil functions anymore. You can use the Swift round() with rounding rules.

var myCGFloat: CGFloat = 3.001
myCGFloat.round(.down) // 3.0
myCGFloat.round(.up) // 4.0

If you don't wish to modify the original variables, then use rounded().

Notes

• Works with both 32 and 64 bit architectures.

See also

• How to round CGFloat