Struct NSTextPreview

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

Available on crate feature NSWritingToolsCoordinator only.

A snapshot of the text in your view, which the system uses to create user-visible effects.

An NSTextPreview object provides a static image of your view’s text content that the system can use to create animations. You provide preview objects in response to system requests, such as ones from Writing Tools. In addition to creating an image of your view’s text, you also specify the location of that text in your view’s frame rectangle. When creating animations, the system places the image on top of your view’s content and animates changes to the image instead of to your view.

Create an NSTextPreview object in response to specific system requests. Create an image with a transparent background and render your view’s text into the image using the current text attributes. Construct your NSTextPreview object with both the image and the frame rectangle that represents the location of the rendered text in your view’s coordinate system. To highlight specific portions of text, instead of all the text in the image, provide a set of candidate rectangles with the locations of the text you want to highlight.

See also Apple’s documentation

Implementations

impl NSTextPreview

pub unsafe fn initWithSnapshotImage_presentationFrame_candidateRects( this: Allocated<Self>, snapshot_image: &CGImage, presentation_frame: NSRect, candidate_rects: &NSArray<NSValue>, ) -> Retained<Self>

Available on crate feature objc2-core-graphics and Apple only.

Creates a text preview using the specified image and rectangles that indicate the portions of text to highlight.

• Parameters:
• snapshotImage: An image that contains the requested text from your view. Create the image using a transparent background and the current rendering attributes for your text.
• presentationFrame: A rectangle in the coordinate space of your text view. The system uses this rectangle to place your image precisely over your view’s actual text. Set its size to the size of your snapshot image, and set its origin to the point that allows the system to place your image directly over the text.
• candidateRects: An array of <doc ://com.apple.documentation/documentation/foundation/nsvalue> objects, each of which contains an <doc ://com.apple.documentation/documentation/foundation/nsrect> in the coordinate space of your text view. Each rectangle contains a bounding rectangle for text that is part of the preview. When applying visual effects, the system adds highlights only to the text in the specified rectangles.

pub unsafe fn initWithSnapshotImage_presentationFrame( this: Allocated<Self>, snapshot_image: &CGImage, presentation_frame: NSRect, ) -> Retained<Self>

Available on crate feature objc2-core-graphics and Apple only.

Creates a text preview using the specified image.

• Parameters:
• snapshotImage: An image that contains the requested text from your view. Create the image using a transparent background and the current rendering attributes for your text.
• presentationFrame: A rectangle in your frame’s coordinate space. The system uses this rectangle to place your image precisely over your view’s actual text. Set its size to the size of your snapshot image, and set its origin to the point that allows the system to place your image directly over the text.

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

pub unsafe fn previewImage(&self) -> Retained<CGImage>

Available on crate feature objc2-core-graphics and Apple only.

The image that contains the requested text from your view.

You specify this image at initialization time. The system uses it to implement any visual effects involving your view’s text. Create the image with your text on a transparent background.

pub unsafe fn presentationFrame(&self) -> NSRect

The frame rectangle that places the preview image directly over the matching text.

You specify this value at initialization time. The system uses it to position the preview image over the text in your view. Make sure the frame rectangle is in your view’s coordinate space.

pub unsafe fn candidateRects(&self) -> Retained<NSArray<NSValue>>

Rectangles that define the specific portions of text to highlight.

At initialization time, you set this property to an array of <doc ://com.apple.documentation/documentation/foundation/nsvalue> objects, each of which contains an <doc ://com.apple.documentation/documentation/foundation/nsrect> in the coordinate space of the target view. Each rectangle contains a bounding rectangle for text that is part of the preview. When applying visual effects, the system adds highlights only to the text in the specified rectangles.

impl NSTextPreview

Methods declared on superclass NSObject.

pub unsafe fn new(mtm: MainThreadMarker) -> Retained<Self>

Methods from Deref<Target = NSObject>

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

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());

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.

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`
    }
}

Trait Implementations

impl AsRef<AnyObject> for NSTextPreview

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for NSTextPreview

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSTextPreview> for NSTextPreview

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for NSTextPreview

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for NSTextPreview

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for NSTextPreview

const NAME: &'static str = "NSTextPreview"

The name of the Objective-C class that this type represents.

type Super = NSObject

The superclass of this class.

type ThreadKind = dyn MainThreadOnly

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl Debug for NSTextPreview

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for NSTextPreview

type Target = NSObject

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for NSTextPreview

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for NSTextPreview

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for NSTextPreview

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for NSTextPreview

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for NSTextPreview

const ENCODING_REF: Encoding = <NSObject as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for NSTextPreview

impl Eq for NSTextPreview