components/Slider/README.md - external/github.com/material-components/material-components-ios - Git at Google

 <!--docs:
 title: "Sliders"
 layout: detail
 section: components
 excerpt: "Sliders allow users to make selections from a range of values."
 iconId: slider
 path: /catalog/sliders/
 -->

 # Slider

 [![Open bugs badge](https://img.shields.io/badge/dynamic/json.svg?label=open%20bugs&url=https%3A%2F%2Fapi.github.com%2Fsearch%2Fissues%3Fq%3Dis%253Aopen%2Blabel%253Atype%253ABug%2Blabel%253A%255BSlider%255D&query=%24.total_count)](https://github.com/material-components/material-components-ios/issues?q=is%3Aopen+is%3Aissue+label%3Atype%3ABug+label%3A%5BSlider%5D)

 [Sliders](https://material.io/components/sliders/) allow users to make
 selections from a range of values.

 !["Slider with sound icon buttons on each end."](docs/assets/sliders-hero.png)

 **Contents**

 *   [Using sliders](#using-sliders)
 *   [Continuous sliders](#continuous-sliders)
 *   [Discrete sliders](#discrete-sliders)
 *   [Theming sliders](#theming-sliders)
 *   [Differences from UISlider](#differences-from-uislider)

 ## Using sliders

 Sliders reflect a range of values along a bar, from which users may select a single value. They are ideal for adjusting settings such as volume, brightness, or applying image filters.

 ### Installing sliders

 In order to install with [Cocoapods](https://guides.cocoapods.org/using/getting-started.html) first add the component to your `Podfile`:

 ```bash
 pod 'MaterialComponents/Slider'
 ```
 <!--{: .code-renderer.code-renderer--install }-->

 Then run the installer:

 ```bash
 pod install
 ```

 Then import the Slider target:

 <!--<div class="material-code-render" markdown="1">-->
 #### Swift
 ```swift
 import MaterialComponents.MaterialSlider
 ```

 #### Objective-C

 ```objc
 #import "MaterialSlider.h"
 ```
 <!--</div>-->

 ### Typical use

 `MDCSlider` can be be used like a standard `UIControl`.

 <!--<div class="material-code-render" markdown="1">-->
 #### Swift

 ```swift
 override func viewDidLoad() {
   super.viewDidLoad()

   let slider = MDCSlider(frame: CGRect(x: 50, y: 50, width: 100, height: 27))
   slider.addTarget(self,
                    action: #selector(didChangeSliderValue(senderSlider:)),
                    for: .valueChanged)
   view.addSubview(slider)
 }

 func didChangeSliderValue(senderSlider:MDCSlider) {
   print("Did change slider value to: \(senderSlider.value)")
 }
 ```

 #### Objective C

 ```objc
 - (void)viewDidLoad {
   MDCSlider *slider = [[MDCSlider alloc] initWithFrame:CGRectMake(50, 50, 100, 27)];
   [slider addTarget:self
                 action:@selector(didChangeSliderValue:)
       forControlEvents:UIControlEventValueChanged];
   [self.view addSubview:slider];
 }

 - (void)didChangeSliderValue:(MDCSlider *)slider {
   NSLog(@"did change %@ value: %f", NSStringFromClass([slider class]), slider.value);
 }
 ```
 <!--</div>-->

 ### Stateful APIs

 `MDCSlider` exposes stateful APIs to customize the colors for different control states. In order to use this API you must enable `statefulAPIEnabled` on your `MDCSlider` instances.

 <!--<div class="material-code-render" markdown="1">-->
 #### Swift

 ```swift
  let slider = MDCSlider()
  slider.isStatefulAPIEnabled = true

  // Setting a thumb color for selected state.
  slider.setThumbColor(.red, for: .selected)
 ```

 #### Objective C

 ```objc
  MDCSlider *slider = [[MDCSlider alloc] init];
  slider.statefulAPIEnabled = YES;

  // Setting a thumb color for selected state.
  [slider setThumbColor:[UIColor redColor] forState:UIControlStateSelected];
 ```
 <!--</div>-->

 ### Making sliders accessible

 To help ensure your slider is accessible to as many users as possible, please be sure to review the following recommendations:

 ####  `-accessibilityLabel`

 Set an appropriate `accessibilityLabel` value for your slider. This should reflect what the slider affects.

 <!--<div class="material-code-render" markdown="1">-->
 #### Swift
 ```swift
 slider.accessibilityLabel = "Volume level"
 ```

 #### Objective - C
 ```objc
 slider.accessibilityLabel = @"Volume level";
 ```
 <!--</div>-->

 #### Minimum touch size

 Sliders currently respect the minimum touch size recomended by the Material spec [touch areas should be
 at least 44 points high and 44 wide](https://material.io/design/usability/accessibility.html#understanding-accessibility).
 The height of the slider is set to 27 points so make sure there is sufficient space so that touches don't affect other
 elements.

 **Types**

 There are two types of sliders: 1\. [Continuous slider](#continuous-slider) and 2\.
 [Discrete slider](#discrete-slider)

 !["Slider examples of both continuous and discrete sliders."](docs/assets/sliders-types.png)

 A slider with one thumb is called a single point slider, and a slider with two thumbs is called a range slider.

 _**Note:** Range sliders are not supported on iOS._

 ### Anatomy and key properties

 A slider has a track, one or two thumbs, and optional value label. A discrete
 slider also has tick marks.

 ![Slider anatomy diagram](docs/assets/sliders-anatomy.png)

 1.  Track
 2.  Thumb
 3.  Value label (optional)
 4.  Tick mark (discrete sliders)

 #### Track attributes

 &nbsp;                                      | Attribute                | Related method(s)                                         | Default value
 ------------------------------------------- | ------------------------ | --------------------------------------------------------- | -------------
 **Min value**                               | `minimumValue`      | `-setMinimumValue:`<br/>`-minimumValue`                          | 0
 **Max value**                               | `maximumValue`        | `-setMaximumValue:`<br/>`-maximumValue`                        | 1
 **Number of discrete values**              | `numberOfDiscreteValues` | `-setNumberOfDiscreteValues:`<br/>`-numberOfDiscreteValues`  | N/A
 **Is discrete**                   | `discrete` | `-setIsDiscrete:`<br/>`-isDiscrete`  | `NO`
 **Height**                                  | `trackHeight`        | `-setTrackHeight:`<br/>`-trackHeight`                     | 2
 **Track background color**                  | NA | `-setTrackBackgroundColor:forState:` <br/> `-trackBackgroundColorForState:` | Black at 26% opacity
 **Track fill color**                        | NA | `-setTrackFillColor:forState:`<br/>`-trackFillColorForState:` | Primary color

 #### Thumb attributes

 &nbsp;           | Attribute              | Related method(s)                                                                 | Default value
 ---------------- | ---------------------- | --------------------------------------------------------------------------------- | -------------
 **Thumb color**  | NA                     | `-setThumbColor:forState:` <br/> `-thumbColorForState:`                           | Primary color
 **Radius**       | `thumbRadius`          | `-setThumbRadius:`<br/>`-thumbRadius`                                             | 6
 **Elevation**    | `thumbElevation`   | `-setThumbElevation:`<br/>`thumbElevation`                                            | 0
 **Ripple color**   | `rippleColor`        | `-setRippleColor:`<br/>`-rippleColor`                                            | `nil`
 **Ripple radius**  | `thumbRippleMaximumRadius`       | `-setThumbRippleMaximumRadius:`<br/>`-thumbRippleMaximumRadius`       | 0

 #### Value label attributes

 &nbsp;        | Attribute           | Related method(s)                           | Default value
 ------------- | ------------------- | ------------------------------------------- | -------------
 **Background color**     | `valueLabelBackgroundColor`    | `-setValueLabelBackgroundColor:` <br/> `-valueLabelBackgroundColor`   | Blue
 **Text color** | `valueLabelTextColor`           | `-valueLabelTextColor:`<br/>`valueLabelTextColor` | White
 **Font**  | `discreteValueLabelFont` | `-setDiscreteValueLabelFont:`<br/>`-discreteValueLabelFont`   | N/A

 #### Tick mark attributes

 &nbsp;                              | Attribute               | Related method(s)                                       | Default value
 ----------------------------------- | ----------------------- | ------------------------------------------------------- | -------------
 **Background tick color**           | N/A         | `-setBackgroundTrackTickColor:forState:`<br/>`-backgroundTrackTickColorForState:` | Black
 **Filled tick color**                | N/A         | `-setFilledTrackTickColor:forState:`<br/>`-filledTrackTickColorForState:` | Black

 ## Continuous sliders

 Continuous sliders allow users to make meaningful selections that don’t require
 a specific value.

 #### Continuous single point slider example

 Source code:
 *   `MDCSlider`
     *   [Class source](https://github.com/material-components/material-components-ios/tree/develop/components/Slider)

 !["Continuous slider from 0 to 100, set at a value of 70."](docs/assets/continuous-slider.png)

 <!--<div class="material-code-render" markdown="1">-->
 #### Swift

 ```swift
 let slider = MDCSlider()
 slider.minimumValue = 0
 slider.maximumValue = 100
 slider.value = 70
 ```

 #### Objective C

 ```objc
 MDCSlider *slider = [[MDCSlider alloc] init];
 slider.minimumValue = 0.0f;
 slider.maximumValue = 100.0f;
 slider.value = 70.0f;
 ```
 <!--</div>-->

 ## Discrete sliders

 #### Discrete single point slider example

 Source code:
 *   `MDCSlider`
     *   [Class source](https://github.com/material-components/material-components-ios/tree/develop/components/Slider)

 !["Discrete slider from 0 to 100, set at a value of 70."](docs/assets/discrete-slider.png)

 <!--<div class="material-code-render" markdown="1">-->
 #### Swift
 ```swift
 let slider = MDCSlider()
 slider.minimumValue = 0
 slider.maximumValue = 100
 slider.value = 70
 slider.discrete = true
 slider.numberOfDiscreteValues = 10
 slider.shouldDisplayDiscreteValueLabel = false
 ```

 #### Objective
 ```objc
 MDCSlider *slider = [[MDCSlider alloc] init];
 slider.minimumValue = 0.0f;
 slider.maximumValue = 100.0f;
 slider.value = 70.0f;
 slider.discrete = YES;
 slider.numberOfDiscreteValues = 10;
 slider.shouldDisplayDiscreteValueLabel = NO;
 ```
 <!--</div>-->

 ## Theming sliders

 `MDCSlider` has no recommended theming mechanism. Configure colors using the properties and stateful APIs exposed on the slider.

 ## Differences from UISlider

 ### UISlider APIs not present in MDCSlider

 * Setting the left/right icons via `minimumValueImage` and `maximumValueImage`.
 * Setting the thumb image via `setThumbImage:forState:`.
 * Setting the right/left track images (for a custom track) via `setMinimumTrackImage:forState:` and `setMaximumTrackImage:forState:`.

 ### UISlider APIs with different names in MDCSlider

 * The UISlider API `minimumTrackTintColor` has an equivalent API `setTrackFillColor:forState:` in MDCSlider. This API must first be enabled by setting `statefulAPIEnabled` to `YES`.
 * The UISlider API `maximumTrackTintColor` has an equivalent API `setTrackBackgroundColor:forState:` in MDCSlider. This API must first be enabled by setting `statefulAPIEnabled = YES`.
 * The UISlider API `thumbTintColor` has an equivalent API `setThumbColor:forState:` in MDCSlider.  This API must first be enabled by setting `statefulAPIEnabled = YES`.

 ### MDCSlider enhancements not in MDCSlider

 * MDCSlider can behave as a [Material Discrete Slider](https://material.io/components/sliders/#discrete-slider) by setting `discrete = YES` and `numberOfDiscreteValues` to a value greater than or equal to 2. Discrete sliders only allow their calculated discrete values to be selected as the Slider's value. If `numberOfDiscreteValues` is less than 2, then the Slider will behave as a [Material Continuous Slider](https://material.io/components/sliders/#continuous-slider).
 * For Discrete Sliders, the track tick color is configured with the `setFilledTrackTickColor:forState:` and `setBackgroundTrackTickColor:forState:` APIs. The filled track ticks are those overlapping the filled/active part of the Slider. The background track ticks are found in any other portions of the track. These APIs must first be enabled by setting `statefulAPIEnabled = YES`.
 * Track tick marks can be made shown always, never, or only when dragging via the `trackTickVisibility` API. If `numberOfDiscreteValues` is less than 2, then tick marks will never be shown.
 * An anchor point can be set via `filledTrackAnchorValue` to control the starting position of the filled track.
 * The track can be made taller (or shorter) by setting the value of `trackHeight`.

 ### `-accessibilityActivate`

 MDCSlider's behavior is very similar to that of UISlider, but it's not exactly the same. On an
 `accessibilityActivate` event, the value moves one sixth of the amount between the current value and the
 midpoint value.
	<!--docs:
	title: "Sliders"
	layout: detail
	section: components
	excerpt: "Sliders allow users to make selections from a range of values."
	iconId: slider
	path: /catalog/sliders/
	-->

	# Slider

	[![Open bugs badge](https://img.shields.io/badge/dynamic/json.svg?label=open%20bugs&url=https%3A%2F%2Fapi.github.com%2Fsearch%2Fissues%3Fq%3Dis%253Aopen%2Blabel%253Atype%253ABug%2Blabel%253A%255BSlider%255D&query=%24.total_count)](https://github.com/material-components/material-components-ios/issues?q=is%3Aopen+is%3Aissue+label%3Atype%3ABug+label%3A%5BSlider%5D)

	[Sliders](https://material.io/components/sliders/) allow users to make
	selections from a range of values.

	!["Slider with sound icon buttons on each end."](docs/assets/sliders-hero.png)

	Contents

	* [Using sliders](#using-sliders)
	* [Continuous sliders](#continuous-sliders)
	* [Discrete sliders](#discrete-sliders)
	* [Theming sliders](#theming-sliders)
	* [Differences from UISlider](#differences-from-uislider)

	## Using sliders

	Sliders reflect a range of values along a bar, from which users may select a single value. They are ideal for adjusting settings such as volume, brightness, or applying image filters.

	### Installing sliders

	In order to install with [Cocoapods](https://guides.cocoapods.org/using/getting-started.html) first add the component to your `Podfile`:

	```bash
	pod 'MaterialComponents/Slider'
	```
	<!--{: .code-renderer.code-renderer--install }-->

	Then run the installer:

	```bash
	pod install
	```

	Then import the Slider target:

	<!--<div class="material-code-render" markdown="1">-->
	#### Swift
	```swift
	import MaterialComponents.MaterialSlider
	```

	#### Objective-C

	```objc
	#import "MaterialSlider.h"
	```
	<!--</div>-->

	### Typical use

	`MDCSlider` can be be used like a standard `UIControl`.

	<!--<div class="material-code-render" markdown="1">-->
	#### Swift

	```swift
	override func viewDidLoad() {
	super.viewDidLoad()

	let slider = MDCSlider(frame: CGRect(x: 50, y: 50, width: 100, height: 27))
	slider.addTarget(self,
	action: #selector(didChangeSliderValue(senderSlider:)),
	for: .valueChanged)
	view.addSubview(slider)
	}

	func didChangeSliderValue(senderSlider:MDCSlider) {
	print("Did change slider value to: \(senderSlider.value)")
	}
	```

	#### Objective C

	```objc
	- (void)viewDidLoad {
	MDCSlider *slider = [[MDCSlider alloc] initWithFrame:CGRectMake(50, 50, 100, 27)];
	[slider addTarget:self
	action:@selector(didChangeSliderValue:)
	forControlEvents:UIControlEventValueChanged];
	[self.view addSubview:slider];
	}

	- (void)didChangeSliderValue:(MDCSlider *)slider {
	NSLog(@"did change %@ value: %f", NSStringFromClass([slider class]), slider.value);
	}
	```
	<!--</div>-->

	### Stateful APIs

	`MDCSlider` exposes stateful APIs to customize the colors for different control states. In order to use this API you must enable `statefulAPIEnabled` on your `MDCSlider` instances.

	<!--<div class="material-code-render" markdown="1">-->
	#### Swift

	```swift
	let slider = MDCSlider()
	slider.isStatefulAPIEnabled = true

	// Setting a thumb color for selected state.
	slider.setThumbColor(.red, for: .selected)
	```

	#### Objective C

	```objc
	MDCSlider *slider = [[MDCSlider alloc] init];
	slider.statefulAPIEnabled = YES;

	// Setting a thumb color for selected state.
	[slider setThumbColor:[UIColor redColor] forState:UIControlStateSelected];
	```
	<!--</div>-->

	### Making sliders accessible

	To help ensure your slider is accessible to as many users as possible, please be sure to review the following recommendations:

	#### `-accessibilityLabel`

	Set an appropriate `accessibilityLabel` value for your slider. This should reflect what the slider affects.

	<!--<div class="material-code-render" markdown="1">-->
	#### Swift
	```swift
	slider.accessibilityLabel = "Volume level"
	```

	#### Objective - C
	```objc
	slider.accessibilityLabel = @"Volume level";
	```
	<!--</div>-->

	#### Minimum touch size

	Sliders currently respect the minimum touch size recomended by the Material spec [touch areas should be
	at least 44 points high and 44 wide](https://material.io/design/usability/accessibility.html#understanding-accessibility).
	The height of the slider is set to 27 points so make sure there is sufficient space so that touches don't affect other
	elements.

	Types

	There are two types of sliders: 1\. [Continuous slider](#continuous-slider) and 2\.
	[Discrete slider](#discrete-slider)

	!["Slider examples of both continuous and discrete sliders."](docs/assets/sliders-types.png)

	A slider with one thumb is called a single point slider, and a slider with two thumbs is called a range slider.

	_Note: Range sliders are not supported on iOS._

	### Anatomy and key properties

	A slider has a track, one or two thumbs, and optional value label. A discrete
	slider also has tick marks.

	![Slider anatomy diagram](docs/assets/sliders-anatomy.png)

	1. Track
	2. Thumb
	3. Value label (optional)
	4. Tick mark (discrete sliders)

	#### Track attributes

	\| Attribute \| Related method(s) \| Default value
	------------------------------------------- \| ------------------------ \| --------------------------------------------------------- \| -------------
	Min value \| `minimumValue` \| `-setMinimumValue:`<br/>`-minimumValue` \| 0
	Max value \| `maximumValue` \| `-setMaximumValue:`<br/>`-maximumValue` \| 1
	Number of discrete values \| `numberOfDiscreteValues` \| `-setNumberOfDiscreteValues:`<br/>`-numberOfDiscreteValues` \| N/A
	Is discrete \| `discrete` \| `-setIsDiscrete:`<br/>`-isDiscrete` \| `NO`
	Height \| `trackHeight` \| `-setTrackHeight:`<br/>`-trackHeight` \| 2
	Track background color \| NA \| `-setTrackBackgroundColor:forState:` <br/> `-trackBackgroundColorForState:` \| Black at 26% opacity
	Track fill color \| NA \| `-setTrackFillColor:forState:`<br/>`-trackFillColorForState:` \| Primary color

	#### Thumb attributes

	\| Attribute \| Related method(s) \| Default value
	---------------- \| ---------------------- \| --------------------------------------------------------------------------------- \| -------------
	Thumb color \| NA \| `-setThumbColor:forState:` <br/> `-thumbColorForState:` \| Primary color
	Radius \| `thumbRadius` \| `-setThumbRadius:`<br/>`-thumbRadius` \| 6
	Elevation \| `thumbElevation` \| `-setThumbElevation:`<br/>`thumbElevation` \| 0
	Ripple color \| `rippleColor` \| `-setRippleColor:`<br/>`-rippleColor` \| `nil`
	Ripple radius \| `thumbRippleMaximumRadius` \| `-setThumbRippleMaximumRadius:`<br/>`-thumbRippleMaximumRadius` \| 0

	#### Value label attributes

	\| Attribute \| Related method(s) \| Default value
	------------- \| ------------------- \| ------------------------------------------- \| -------------
	Background color \| `valueLabelBackgroundColor` \| `-setValueLabelBackgroundColor:` <br/> `-valueLabelBackgroundColor` \| Blue
	Text color \| `valueLabelTextColor` \| `-valueLabelTextColor:`<br/>`valueLabelTextColor` \| White
	Font \| `discreteValueLabelFont` \| `-setDiscreteValueLabelFont:`<br/>`-discreteValueLabelFont` \| N/A

	#### Tick mark attributes

	\| Attribute \| Related method(s) \| Default value
	----------------------------------- \| ----------------------- \| ------------------------------------------------------- \| -------------
	Background tick color \| N/A \| `-setBackgroundTrackTickColor:forState:`<br/>`-backgroundTrackTickColorForState:` \| Black
	Filled tick color \| N/A \| `-setFilledTrackTickColor:forState:`<br/>`-filledTrackTickColorForState:` \| Black

	## Continuous sliders

	Continuous sliders allow users to make meaningful selections that don’t require
	a specific value.

	#### Continuous single point slider example

	Source code:
	* `MDCSlider`
	* [Class source](https://github.com/material-components/material-components-ios/tree/develop/components/Slider)

	!["Continuous slider from 0 to 100, set at a value of 70."](docs/assets/continuous-slider.png)

	<!--<div class="material-code-render" markdown="1">-->
	#### Swift

	```swift
	let slider = MDCSlider()
	slider.minimumValue = 0
	slider.maximumValue = 100
	slider.value = 70
	```

	#### Objective C

	```objc
	MDCSlider *slider = [[MDCSlider alloc] init];
	slider.minimumValue = 0.0f;
	slider.maximumValue = 100.0f;
	slider.value = 70.0f;
	```
	<!--</div>-->

	## Discrete sliders

	#### Discrete single point slider example

	Source code:
	* `MDCSlider`
	* [Class source](https://github.com/material-components/material-components-ios/tree/develop/components/Slider)

	!["Discrete slider from 0 to 100, set at a value of 70."](docs/assets/discrete-slider.png)

	<!--<div class="material-code-render" markdown="1">-->
	#### Swift
	```swift
	let slider = MDCSlider()
	slider.minimumValue = 0
	slider.maximumValue = 100
	slider.value = 70
	slider.discrete = true
	slider.numberOfDiscreteValues = 10
	slider.shouldDisplayDiscreteValueLabel = false
	```

	#### Objective
	```objc
	MDCSlider *slider = [[MDCSlider alloc] init];
	slider.minimumValue = 0.0f;
	slider.maximumValue = 100.0f;
	slider.value = 70.0f;
	slider.discrete = YES;
	slider.numberOfDiscreteValues = 10;
	slider.shouldDisplayDiscreteValueLabel = NO;
	```
	<!--</div>-->

	## Theming sliders

	`MDCSlider` has no recommended theming mechanism. Configure colors using the properties and stateful APIs exposed on the slider.

	## Differences from UISlider

	### UISlider APIs not present in MDCSlider

	* Setting the left/right icons via `minimumValueImage` and `maximumValueImage`.
	* Setting the thumb image via `setThumbImage:forState:`.
	* Setting the right/left track images (for a custom track) via `setMinimumTrackImage:forState:` and `setMaximumTrackImage:forState:`.

	### UISlider APIs with different names in MDCSlider

	* The UISlider API `minimumTrackTintColor` has an equivalent API `setTrackFillColor:forState:` in MDCSlider. This API must first be enabled by setting `statefulAPIEnabled` to `YES`.
	* The UISlider API `maximumTrackTintColor` has an equivalent API `setTrackBackgroundColor:forState:` in MDCSlider. This API must first be enabled by setting `statefulAPIEnabled = YES`.
	* The UISlider API `thumbTintColor` has an equivalent API `setThumbColor:forState:` in MDCSlider. This API must first be enabled by setting `statefulAPIEnabled = YES`.

	### MDCSlider enhancements not in MDCSlider

	* MDCSlider can behave as a [Material Discrete Slider](https://material.io/components/sliders/#discrete-slider) by setting `discrete = YES` and `numberOfDiscreteValues` to a value greater than or equal to 2. Discrete sliders only allow their calculated discrete values to be selected as the Slider's value. If `numberOfDiscreteValues` is less than 2, then the Slider will behave as a [Material Continuous Slider](https://material.io/components/sliders/#continuous-slider).
	* For Discrete Sliders, the track tick color is configured with the `setFilledTrackTickColor:forState:` and `setBackgroundTrackTickColor:forState:` APIs. The filled track ticks are those overlapping the filled/active part of the Slider. The background track ticks are found in any other portions of the track. These APIs must first be enabled by setting `statefulAPIEnabled = YES`.
	* Track tick marks can be made shown always, never, or only when dragging via the `trackTickVisibility` API. If `numberOfDiscreteValues` is less than 2, then tick marks will never be shown.
	* An anchor point can be set via `filledTrackAnchorValue` to control the starting position of the filled track.
	* The track can be made taller (or shorter) by setting the value of `trackHeight`.

	### `-accessibilityActivate`

	MDCSlider's behavior is very similar to that of UISlider, but it's not exactly the same. On an
	`accessibilityActivate` event, the value moves one sixth of the amount between the current value and the
	midpoint value.