UIImageView keep aspect ratio, but fit to width

ios swift uiimageview uiimage aspect-ratio
SirRupertIII picture SirRupertIII · Sep 24, 2015 · Viewed 21.9k times · Source

I have a UIImageView with a fixed width and height. I don't want to change the frame of the UIImageView. I want to have it hold an image where I keep the aspect ratio and I fit the width and let the image be either too tall, or too short for the UIImageView's frame. Like this:

UIImageView frame

The red is the UIImageView's frame. The gray is the actual image as it's displayed.

Answer

Glenn picture Glenn · Sep 24, 2015

I think the best way to do it is to play with the mode of your imageView (Aspect Fill, Aspect Width, etc) and this is based on the ratio between the width and height of the image

if image.width > image.height {
    imageView.contentMode = UIViewContentModeScaleAspectFit
    //since the width > height we may fit it and we'll have bands on top/bottom
} else {
  imageView.contentMode = UIViewContentModeScaleAspectFill
  //width < height we fill it until width is taken up and clipped on top/bottom
}

UIViewContentModeScaleAspectFit

Scales the content to fit the size of the view by maintaining the aspect ratio. Any remaining area of the view’s bounds is transparent.

UIViewContentModeScaleAspectFill

Scales the content to fill the size of the view. Some portion of the content may be clipped to fill the view’s bounds.

I haven't tested it but off the top of my head this seems right

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