Global Variable

kCGDisplayStreamPreserveAspectRatio

This key specifies whether the display stream preserves the aspect ratio of the source pixel data. If this key is not included in the dictionary, then the aspect ratio is preserved. If the aspect ratio is preserved, then the display stream adds black bars to the output data. If the aspect ratio is not preserved, then the pixel data is stretched to fit the output buffer’s dimensions. The value associated with the key must be a CFBoolean.

Declaration

const CFStringRef kCGDisplayStreamPreserveAspectRatio;