The literal meaning of scale and aspect in the contentMode of UIView, uiviewcontentmode

The literal meaning of scale and aspect in the contentMode of UIView, uiviewcontentmode

Scale means scaling. If it appears in contentMode, it is necessary to change the image size.
Aspect means the aspect ratio. In contentMode, it means to keep the aspect ratio of the image and keep the image unchanged.

Scale aspect fill: scale the image to make the image full of the container (fill) while maintaining the aspect ratio (aspect ).
Scale aspect fit: scale the image to make the image show (fit) in the container while maintaining the aspect ratio (aspect ).
Scale to fill: scale the image to fill the container. Because there is no aspect, the aspect ratio is not maintained.

Eg.