A control that indicates a value on a linear scale.


Level indicators provide a visual representation of a level or amount of something, using discrete values. While similar to NSSlider, it provides a more customized visual feedback to the user. Level indicators do not have a “knob” indicating the current setting or allowing the user to adjust settings. The supported indicator styles include:

  • A capacity style level indicator. The continuous mode for this style is often used to indicate conditions such as how much data is on hard disk. The discrete mode is similar to audio level indicators in audio playback applications. You can specify both a warning value and a critical value that provides additional visual feedback to the user.

  • A ranking style level indicator. This style is similar to a star ranking display. You can also specify your own ranking image.

  • A relevancy style level indicator. This style can be used to display the relevancy of an item, such as a search result.

NSLevelIndicator uses an NSLevelIndicatorCell to implement much of the control’s functionality. NSLevelIndicator provides cover methods for most of the NSLevelIndicatorCell methods, which invoke the corresponding cell method.

Nested Types


Constants used to specify a level indicator's appearance.


Configuring the Range of Values

var minValue: Double

The receiver’s minimum value.

var maxValue: Double

The receiver’s maximum value.

var warningValue: Double

The receiver’s warning value.

var criticalValue: Double

The receiver’s critical value.

Managing Tick Marks and Style

var tickMarkPosition: NSTickMarkPosition

Determines how the receiver’s tick marks are aligned with it.

var numberOfTickMarks: Int

The number of tick marks associated with the receiver.

var numberOfMajorTickMarks: Int

The number of major tick marks associated with the receiver.

func tickMarkValue(at: Int)

Returns the receiver’s value represented by the tick mark at the specified index (the minimum-value tick mark has an index of 0).

func rectOfTickMark(at: Int)

Returns the bounding rectangle of the tick mark identified by the specified index (the minimum-value tick mark is at index 0).

var levelIndicatorStyle: NSLevelIndicatorStyle

The appearance of the indicator.


Inherits From