[ios] How to adjust an UIButton's imageSize?

How can I adjust the image size of the UIButton? I am setting the image like this:

[myLikesButton setImage:[UIImage imageNamed:@"icon-heart.png"] forState:UIControlStateNormal];

However this fills up the image to the full button, how do I make the image smaller?

One approach is to resize the UIImage in code like the following. Note: this code only scales by height, but you can easily adjust the function to scale by width as well.

let targetHeight = CGFloat(28)
let newImage = resizeImage(image: UIImage(named: "Image.png")!, targetHeight: targetHeight)
button.setImage(newImage, for: .normal)

fileprivate func resizeImage(image: UIImage, targetHeight: CGFloat) -> UIImage {
    // Get current image size
    let size = image.size

    // Compute scaled, new size
    let heightRatio = targetHeight / size.height
    let newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio)
    let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)

    // Create new image
    UIGraphicsBeginImageContextWithOptions(newSize, false, 0)
    image.draw(in: rect)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    // Return new image
    return newImage!
}

you can use imageEdgeInsets property The inset or outset margins for the rectangle around the button’s image.

 [self.btn setImageEdgeInsets:UIEdgeInsetsMake(6, 6, 6, 6)];

A positive value shrinks, or insets, that edge—moving. A negative value expands, or outsets, that edge.

Swift 3:

button.setImage(UIImage(named: "checkmark_white"), for: .normal)
button.contentVerticalAlignment = .fill
button.contentHorizontalAlignment = .fill
button.imageEdgeInsets = UIEdgeInsetsMake(10, 10, 10, 10)

i think, your image size is also same as button size then you put image in background of the button like :

[myLikesButton setBackgroundImage:[UIImage imageNamed:@"icon-heart.png"] forState:UIControlStateNormal];

you mast have same size of image and button.i hope you understand my point.

Updated for Swift 3

yourButtonName.imageEdgeInsets = UIEdgeInsetsMake(10, 10, 10, 10)

If your image is too large (and you can't/don't want to just made the image smaller), a combination of the first two answers works great.

addButton.imageView?.contentMode = .scaleAspectFit
addButton.imageEdgeInsets = UIEdgeInsetsMake(15.0, 15.0, 15.0, 5.0)

Unless you get the image insets just right, the image will be skewed without changing the contentMode.

Swift 3

I set myButton width and height to 40 and my padding from EdgeInsetsMake is 15 all sides. I suggest to add a background color to your button to see the actual padding.

myButton.backgroundColor = UIColor.gray // sample color to check padding
myButton.imageView?.contentMode = .scaleAspectFit
myButton.imageEdgeInsets = UIEdgeInsetsMake(15, 15, 15, 15)

Here is the other solution to scale an imageView of UIButton.

button.imageView?.layer.transform = CATransform3DMakeScale(0.8, 0.8, 0.8)

With the help of Tim C's answer, I was able to create an extension on UIButton using Swift that allows you to specify the image frame by using the .setImage() function with an extra frame parameter

extension UIButton{

    func setImage(image: UIImage?, inFrame frame: CGRect?, forState state: UIControlState){
        self.setImage(image, forState: state)

        if let frame = frame{
            self.imageEdgeInsets = UIEdgeInsets(
                top: frame.minY - self.frame.minY,
                left: frame.minX - self.frame.minX,
                bottom: self.frame.maxY - frame.maxY,
                right: self.frame.maxX - frame.maxX
            )
        }
    }

}

Using this, if you wanted to set the frame of a UIButton to CGRectMake(0, 0, 64, 64), and set the image of it to myImage with a frame of CGRectMake(8, 8, 48, 48), you could use

let button: UIButton = UIButton(frame: CGRectMake(0, 0, 64, 64))
button.setImage(
    myImage,
    inFrame: CGRectMake(8, 8, 48, 48),
    forState: UIControlState.Normal
)

You can also do that from inteface builder like this.

I think it's helpful.

Tim's answer is correct, however I wanted to add another suggestion, because in my case there was a simpler solution altogether.

I was looking to set the UIButton image insets because I didn't realize that I could set the content mode on the button's UIImageView, which would have prevented the need to use UIEdgeInsets and hard-coded values altogether. Simply access the underlying imageview on the button and set the content mode:

myButton.imageView.contentMode = UIViewContentModeScaleAspectFit;

See UIButton doesn't listen to content mode setting?

Swift 3

myButton.imageView?.contentMode = .scaleAspectFit

When changing icon size with UIEdgeInsetsMake(top, left, bottom, right), keep in mind button dimensions and the ability of UIEdgeInsetsMake to work with negative values as if they are positive.

Example: Two buttons with height 100 and aspect 1:1.

left.imageEdgeInsets = UIEdgeInsetsMake(40, 0, 40, 0)
right.imageEdgeInsets = UIEdgeInsetsMake(40, 0, 40, 0)

left.imageEdgeInsets = UIEdgeInsetsMake(40, 0, 40, 0)
right.imageEdgeInsets = UIEdgeInsetsMake(45, 0, 45, 0)

left.imageEdgeInsets = UIEdgeInsetsMake(40, 0, 40, 0)
right.imageEdgeInsets = UIEdgeInsetsMake(60, 0, 60, 0)

Examples 1 and 3 are identical since ABS(100 - (40 + 40)) = ABS(100 - (60 + 60))

Swift 4

You would need to use these two lines of code, in this specific order. All you need is to change the top and bottom value of the edge insets.

addButton.imageView?.contentMode = .scaleAspectFit
addButton.imageEdgeInsets = UIEdgeInsetsMake(10.0, 0.0, 10.0, 0.0)

Heres the Swift version:

myButton.imageEdgeInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)

Updated for Swift > 5

set the size:

button.frame = CGRect(x: 0, y: 0, width: 44, height: 44)

set margins:

button.imageEdgeInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)