Struct ARMatteGenerator

Source

pub struct ARMatteGenerator { /* private fields */ }

Available on crate features ARMatteGenerator and objc2 only.

Expand description

An object designed to generate either full resolution or half resolution matte given the ARFrame.

The caller initializes the object once and calls the alpha matte generation API for every ARFrame with the captured image and segmentation stencil.

Implementations§

Source §

impl ARMatteGenerator

Source

pub unsafe fn initWithDevice_matteResolution( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, matte_resolution: ARMatteResolution, ) -> Retained<Self>

Available on crate feature objc2-metal only.

Initializes an instance of ARMatteGenerator.

For efficient creation of alpha mattes in real time it is recommended to instantiate this object only once and to generate an alpha matte for every incoming frame.

See: ARFrame

See: -[ARMatteGenerator generateMatteFromFrame:commandBuffer:]

Parameter device: The device the filter will run on.

Parameter matteResolution: The resolution at which the matte is to be generated. Set using one of the values from ‘ARMatteResolution’.

See: ARMatteResolution

Returns: Instance of ARMatteGenerator.

Source

pub unsafe fn generateMatteFromFrame_commandBuffer( &self, frame: &ARFrame, command_buffer: &ProtocolObject<dyn MTLCommandBuffer>, ) -> Retained<ProtocolObject<dyn MTLTexture>>

Available on crate features ARFrame and objc2-metal only.

Generates alpha matte at either full resolution or half the resolution of the captured image.

Parameter frame: Current ARFrame containing camera image and segmentation stencil. The caller is to ensure that a valid segmentation buffer is present.

Parameter commandBuffer: Metal command buffer for encoding matting related operations. The command buffer is committed by the caller externally.

Returns: Alpha matte MTLTexture for the given ARFrame at full resolution or half resolution as chosen by the caller during initialization.

Source

pub unsafe fn generateDilatedDepthFromFrame_commandBuffer( &self, frame: &ARFrame, command_buffer: &ProtocolObject<dyn MTLCommandBuffer>, ) -> Retained<ProtocolObject<dyn MTLTexture>>

Available on crate features ARFrame and objc2-metal only.

Generates dilated depth at the resolution of the segmentation stencil.

The caller can use depth information when compositing a virtual object with the captured scene. This API returns the dilated linear depth to the caller. The reprojection of this depth to the caller’s scene space is carried out externally.

Parameter frame: Current ARFrame containing camera image and estimated depth buffer. The caller is to ensure that a valid depth buffer is present.

Parameter commandBuffer: Metal command buffer for encoding depth dilation operations. The command buffer is committed by the caller externally.

Returns: Dilated depth MTLTexture for the given ARFrame at the segmentation stencil resolution. The texture consists of a single channel and is of type float16.

Source

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

Unavailable

Source

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

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>§

Source

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

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());

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`
    }
}