aspectFit

aspectFit is a content mode used in graphical user interfaces, particularly within Apple's development frameworks like UIKit and SwiftUI, to describe how an image or other visual content should be resized to fit within a given bounding box. When an image is set to aspectFit, it scales down while maintaining its original aspect ratio until the entire image fits within the target dimensions. This means that no part of the image will be cropped, but there might be empty space (letterboxing or pillarboxing) within the bounding box if the aspect ratio of the image does not match the aspect ratio of the container.

This mode is often contrasted with aspectFill. aspectFill scales the content to fill the entire bounding box, maintaining its aspect ratio. However, this can result in parts of the content being cropped if the aspect ratios do not match. aspectFit prioritizes showing the entire image over filling the available space. It's a common choice when it's important for users to see the complete picture, even if it means introducing some blank areas. Developers select aspectFit to ensure the integrity of the image's composition and to avoid cutting off any important visual elements. This mode is widely used for displaying profile pictures, thumbnails, and other images where a full view is desired.