how to convert Int32 value to CGFloat in swift?

Question

Here my code. I am passing two values into CGRectMake(..) and getting and error.

let width = CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription as CMVideoFormatDescriptionRef!).width
// return Int32 value

let height = CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription as CMVideoFormatDescriptionRef!).height
// return Int32 value

myLayer?.frame = CGRectMake(0, 0, width, height)
// returns error: '`Int32`' not convertible to `CGFloat`

How can I convert Int32 to CGFloat to not return an error?

Torrent

Direct Int to CGFloat conversion might be time consuming. Consider using different methods if API is available. For example, you can create CGSize from Int, and then do let dividedSize =size.applying(.init(scaleX: 0.5, y: 0.5)), instead of converting Int's to CGFloat for dividing. – Geomorphic

Answer 1

To convert between numerical data types create a new instance of the target type, passing the source value as parameter. So to convert an Int32 to a CGFloat:

let int: Int32 = 10
let cgfloat = CGFloat(int)

In your case you can either do:

let width = CGFloat(CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription as CMVideoFormatDescriptionRef!).width)
let height = CGFloat(CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription as CMVideoFormatDescriptionRef!).height)

myLayer?.frame = CGRectMake(0, 0, width, height)

or:

let width = CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription as CMVideoFormatDescriptionRef!).width
let height = CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription as CMVideoFormatDescriptionRef!).height

myLayer?.frame = CGRectMake(0, 0, CGFloat(width), CGFloat(height))

Note that there is no implicit or explicit type casting between numeric types in swift, so you have to use the same pattern also for converting a Int to Int32 or to UInt etc.

Omnirange

I wonder, is it safe to do this conversion on 32-bit systems, where int32 is (still) 32 bits, however CGFloat is 32 bits too. Taking in account that latter is a floating point and this answer, there will be a loss of precision. Please, correct me if I'm wrong. – Constitutionally

I wonder why let x: Int = 1; let y: Int = 2; let progress = CGFloat(x / y) wasn't working for me. However, individually wrapping x and y as CGFloats worked. – Heterogynous

@AndrewKirna not working because it doesn't compile, or because of an unexpected result? In the latter case, the result is 0. x and y are Int, the division truncates, so 1 / 2 = 0 However if you convert at least one to CGFloat, the operands are both CGFLoat, so the expression evaluates to 0.5 – Omnirange

@Antonio, it was because of an unexpected result. But that makes sense...I forgot all Integer division takes the floor of the result even though I'm converting the result to a CGFloat. In other words, the float version of 0 will still be 0. – Heterogynous

Expression took 37ms to type-check (limit: 33ms) – Nazarite

Answer 2

Just explicitly convert width and height to CGFloat using the CGFloat's initializer:

myLayer?.frame = CGRectMake(0, 0, CGFloat(width), CGFloat(height))

Farra