Struct UIFocusHaloEffect

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pub struct UIFocusHaloEffect { /* private fields */ }

Available on crate feature UIFocusEffect only.

Expand description

Apple’s documentation

Implementations§

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impl UIFocusHaloEffect

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pub fn effectWithRect(rect: CGRect) -> Retained<Self>

Available on crate feature objc2-core-foundation only.

Creates a rectangular halo.

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pub fn effectWithRoundedRect_cornerRadius_curve( rect: CGRect, corner_radius: CGFloat, curve: &CALayerCornerCurve, ) -> Retained<Self>

Available on crate feature objc2-core-foundation and crate feature objc2-quartz-core and non-watchOS only.

Creates a rounded rect halo using the specified corner radius and corner curve.

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pub fn effectWithPath(bezier_path: &UIBezierPath) -> Retained<Self>

Available on crate feature UIBezierPath only.

Creates a halo with the given bezier path.

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pub fn containerView(&self, mtm: MainThreadMarker) -> Option<Retained<UIView>>

Available on crate features UIResponder and UIView only.

Container view in which to place the effect. When not set, the container is determined automatically from the focus item that provided this effect and the referenceView(if present).

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pub fn setContainerView(&self, container_view: Option<&UIView>)

Available on crate features UIResponder and UIView only.

Setter for containerView.

This is a weak property.

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pub fn referenceView(&self, mtm: MainThreadMarker) -> Option<Retained<UIView>>

Available on crate features UIResponder and UIView only.

When set, the halo is placed above this view. If a containerViewis also set, the referenceViewmust be a descendant of the containerView.The system will ensure that the halo is in the container but visually above the referenceView.

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pub fn setReferenceView(&self, reference_view: Option<&UIView>)

Available on crate features UIResponder and UIView only.

Setter for referenceView.

This is a weak property.

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pub fn position(&self) -> UIFocusHaloEffectPosition

Position of the halo relative to the specified shape. Defaults to UIFocusHaloEffectPositionAutomatic.

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pub fn setPosition(&self, position: UIFocusHaloEffectPosition)

Setter for position.

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impl UIFocusHaloEffect

Methods declared on superclass UIFocusEffect.

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pub fn effect() -> Retained<Self>

Creates a default system effect using metrics inferred from the focus item.

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

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

Methods from Deref<Target = NSObject>§

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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

Available on crate feature UIIndirectScribbleInteraction only.

Dynamically find the class of this object.

§Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

§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());

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

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

Available on crate feature UIIndirectScribbleInteraction only.

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.

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

Available on crate feature UIIndirectScribbleInteraction only.

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`
    }
}