The source image buffer's clean aperture is scaled to a rectangle fitted inside the destination clean aperture that preserves the source picture aspect ratio.
- iOS 9.0+
- macOS 10.8+
- Mac Catalyst 13.0+
- tvOS 10.2+
The remainder of the destination image buffer is filled with black. If a destination pixel aspect ratio is not set, the source image's pixel aspect ratio is used. The pixel aspect ratio used is set on the destination image buffer.