Returns the preferred opacity for the text highlight.


func MACaptionAppearanceGetBackgroundOpacity(_ domain: MACaptionAppearanceDomain, _ behavior: UnsafeMutablePointer<MACaptionAppearanceBehavior>?) -> CGFloat



The domain to retrieve the preference value from. See MACaptionAppearanceDomain. Pass MACaptionAppearanceDomain.user unless the system defaults are needed for comparison.


A pointer to memory. On return, this memory holds the caption appearance behavior for this preference setting. For possible values see MACaptionAppearanceBehavior. Pass NULL when you do not need the behavior setting.

Return Value

A float value, ranging from 0.0 to 1.0, representing the opacity of the color behind the text and above the window color.

See Also

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