Struct AVCaptureSlider

Source

#[repr(C)]
pub struct AVCaptureSlider { /* private fields */ }

Available on crate features AVCaptureControl and AVCaptureSlider only.

Expand description

An AVCaptureControl for selecting a value from a bounded range of values.

AVCaptureSlider is ideal when your control only needs a single float value. Controls may be added to an AVCaptureSession using -[AVCaptureSession addControl:].

Implementations§

Source §

impl AVCaptureSlider

Source

pub unsafe fn initWithLocalizedTitle_symbolName_minValue_maxValue( this: Allocated<Self>, localized_title: &NSString, symbol_name: &NSString, min_value: c_float, max_value: c_float, ) -> Retained<Self>

Initializes an AVCaptureSlider as a continuous slider between minValue and maxValue.

Parameter localizedTitle: A localized string that describes the slider’s action.

Parameter symbolName: The name of a symbol to represent the slider.

Parameter minValue: The minimum value the slider can have. minValue must be less than maxValue, otherwise an NSInvalidArgumentException is thrown.

Parameter maxValue: The maximum value the slider can have. maxValue must be greater than minValue, otherwise an NSInvalidArgumentException is thrown.

Returns: An AVCaptureSlider instance as a continuous slider between minValue and maxValue.

Continuous sliders are used when any value in the range minValue...maxValue is supported.

Source

pub unsafe fn initWithLocalizedTitle_symbolName_minValue_maxValue_step( this: Allocated<Self>, localized_title: &NSString, symbol_name: &NSString, min_value: c_float, max_value: c_float, step: c_float, ) -> Retained<Self>

Initializes an AVCaptureSlider as a discrete slider where the valid values are between minValue and maxValue with step distance between each value.

Parameter localizedTitle: A localized string that describes the slider’s action.

Parameter symbolName: The name of a symbol to represent the slider.

Parameter minValue: The minimum value the slider can have. minValue must be less than maxValue, otherwise an NSInvalidArgumentException is thrown.

Parameter maxValue: The maximum value the slider can have. maxValue must be greater than minValue, otherwise an NSInvalidArgumentException is thrown.

Parameter step: The distance between each valid value. step must be greater than 0, otherwise an NSInvalidArgumentException is thrown.

Returns: An AVCaptureSlider instance as a discrete slider where the valid values are between minValue and maxValue with step distance between each value.

Discrete sliders are used when only specific values are valid.

Source

pub unsafe fn initWithLocalizedTitle_symbolName_values( this: Allocated<Self>, localized_title: &NSString, symbol_name: &NSString, values: &NSArray<NSNumber>, ) -> Retained<Self>

Initializes an AVCaptureSlider as a discrete slider where values contains the valid values.

Parameter localizedTitle: A localized string that describes the slider’s action.

Parameter symbolName: The name of a symbol to represent the slider.

Parameter values: The only values the slider can have.

Returns: An AVCaptureSlider instance as a discrete slider where values contains the valid values.

Discrete sliders are used when only specific values are valid.

Source

pub unsafe fn value(&self) -> c_float

The current value of the slider.

Because the camera system may be independent from the main thread or MainThreadOnly, value must be changed on actionQueue – the queue provided to setActionQueue:action:. The default value is the slider’s minimum value. A value may only be set if it is within the slider’s minimum and maximum values, otherwise an NSInvalidArgumentException is thrown.

Source

pub unsafe fn setValue(&self, value: c_float)

Setter for value.

Source

pub unsafe fn localizedValueFormat(&self) -> Option<Retained<NSString>>

A localized string defining the presentation of the slider’s value.

To modify the presentation of the slider’s value, set localizedValueFormat to a format string to display the slider’s value with any annotation.

The format string may only contain % @ and no other placeholders like %d, %s, etc. Invalid format strings will result in the value’s default presentation.

Examples of valid format strings are:

% % % for “40%”
% @ fps for “60 fps”
+ % @ for “+ 20”

Source

pub unsafe fn setLocalizedValueFormat( &self, localized_value_format: Option<&NSString>, )

Setter for localizedValueFormat.

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pub unsafe fn prominentValues(&self) -> Retained<NSArray<NSNumber>>

Values in this array may receive unique visual representations or behaviors.

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pub unsafe fn setProminentValues(&self, prominent_values: &NSArray<NSNumber>)

Setter for prominentValues.

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pub unsafe fn localizedTitle(&self) -> Retained<NSString>

A localized string that describes the slider’s action.

Source

pub unsafe fn symbolName(&self) -> Retained<NSString>

The name of a symbol to represent the slider.

Source

pub unsafe fn accessibilityIdentifier(&self) -> Option<Retained<NSString>>

A string that identifies the slider.

Source

pub unsafe fn setAccessibilityIdentifier( &self, accessibility_identifier: Option<&NSString>, )

Setter for accessibilityIdentifier.

Source §

impl AVCaptureSlider

Methods declared on superclass AVCaptureControl.

Source

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

Source

pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = AVCaptureControl>§

Source

pub unsafe fn isEnabled(&self) -> bool

Indicates whether the control should be enabled for user interaction.

The value of this property is a BOOL that determines whether the control should be enabled for user interaction. Clients can set this property to keep a control added to an AVCaptureSession but prevent it from being interacted with by the user. A control’s value may still be changed while it is disabled. The default value is YES.

Source

pub unsafe fn setEnabled(&self, enabled: bool)

Setter for isEnabled.

Methods from Deref<Target = NSObject>§

Source

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

§Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

Source

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T
where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

§Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

Source

pub fn downcast_ref<T>(&self) -> Option<&T>
where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

§Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

§Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

§Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

§Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}