Struct NSScrubberLayout

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

Available on crate feature NSScrubberLayout only.

Expand description

NSScrubberLayoutis an abstract class that describes the layout of items within a NSScrubbercontrol.

Implementations§

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impl NSScrubberLayout

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pub unsafe fn layoutAttributesClass(mtm: MainThreadMarker) -> &'static AnyClass

Specifies a class for describing layout attributes. By default, this is NSScrubberLayoutAttributes,but subclasses may override this method to use a custom subclass of NSScrubberLayoutAttributes.

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pub unsafe fn scrubber(&self) -> Option<Retained<NSScrubber>>

Available on crate features NSResponder and NSScrubber and NSView only.

The NSScrubber control that this layout is assigned to, or nilif the receiver is not assigned to a scrubber.

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pub unsafe fn visibleRect(&self) -> NSRect

The currently visible rectangle, in the coordinate space of the scrubber content. Returns NSZeroRectif the receiver is not assigned to a scrubber.

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

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pub unsafe fn initWithCoder( this: Allocated<Self>, coder: &NSCoder, ) -> Retained<Self>

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pub unsafe fn invalidateLayout(&self)

Signals that layout has been invalidated and the NSScrubber should run a fresh layout pass. Subclasses may define more granular invalidation methods suitable for their own data structures, but those methods should always call up to -invalidateLayout.

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pub unsafe fn prepareLayout(&self)

Following any invalidation in layout, NSScrubberwill call prepareLayouton its layout object prior to requesting any other layout information. Subclasses should use this method to perform upfront calculations and caching. The base implementation of this method does nothing.

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pub unsafe fn scrubberContentSize(&self) -> NSSize

Returns the content size for all elements within the scrubber. The base implementation returns NSZeroSize.

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pub unsafe fn layoutAttributesForItemAtIndex( &self, index: NSInteger, ) -> Option<Retained<NSScrubberLayoutAttributes>>

Returns the layout attributes for a single item within the scrubber. The base implementation returns nil.

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pub unsafe fn layoutAttributesForItemsInRect( &self, rect: NSRect, ) -> Retained<NSSet<NSScrubberLayoutAttributes>>

Returns the set of layout attributes for all items within the provided rectangle. The base implementation returns an empty set.

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pub unsafe fn shouldInvalidateLayoutForSelectionChange(&self) -> bool

If YES,the scrubber will invalidate its layout when the selection changes. The default value is NO.Subclasses should return YESif the selection index affects the item layout.

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pub unsafe fn shouldInvalidateLayoutForHighlightChange(&self) -> bool

If YES,the scrubber will invalidate its layout when an item is highlighted. The default value is NO.Subclasses should return YESif the highlight state affects the item layout.

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pub unsafe fn shouldInvalidateLayoutForChangeFromVisibleRect_toVisibleRect( &self, from_visible_rect: NSRect, to_visible_rect: NSRect, ) -> bool

If YES,the scrubber will invalidate its layout in response to a change in the visible region. The default value is NO.Subclasses which rely on the size or origin of the visible region should return YES.

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pub unsafe fn automaticallyMirrorsInRightToLeftLayout(&self) -> bool

If YES,the layout object will automatically have its inputs and outputs mirrored in right-to-left interfaces. The default value is YES.Subclasses that wish to handle RTL layout manually should return NO.

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impl NSScrubberLayout

Methods declared on superclass NSObject.

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pub unsafe fn new(mtm: MainThreadMarker) -> 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 NSAccessibilityConstants 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 NSAccessibilityConstants 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 NSAccessibilityConstants 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`
    }
}