How to create a blank transparent png in Objective-C?

Question

How can I create a blank png UIImage in Objective C programmatically (let's say 36x36 px)?

Thanks :)

Answer 1

You can open an image context, and then harvest its content immediately, without drawing anything into it. This should produce a blank 36x36 UIImage:

UIGraphicsBeginImageContextWithOptions(CGSizeMake(36, 36), NO, 0.0);
UIImage *blank = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Answer 2

let img = UIImage() // size does not matter for a blank transparent image

When using a blank transparent image, its size does not matter, and I think the imageView.contentMode might be any scalable value, or set it to UIView.ContentMode.scaleAspectFit or UIView.ContentMode.scaleAspectFill if needed.