pub struct MPSCNNLossLabels { /* private fields */ }MPSCNNLoss and MPSCore and MPSState only.Expand description
Dependencies: This depends on Metal.framework.
The MPSCNNLossLabels is used to hold the per-element weights buffer used by both MPSCNNLoss forward filter and MPSNNLossGradient backward filter. The MPSCNNLoss forward filter populates the MPSCNNLossLabels object and the MPSNNLossGradient backward filter consumes the state object.
See also Apple’s documentation
Implementations§
Source§impl MPSCNNLossLabels
impl MPSCNNLossLabels
Sourcepub unsafe fn init(this: Allocated<Self>) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>
MPSNeuralNetwork only.Use one of the interfaces below instead.
Sourcepub unsafe fn initWithDevice_labelsDescriptor(
this: Allocated<Self>,
device: &ProtocolObject<dyn MTLDevice>,
labels_descriptor: &MPSCNNLossDataDescriptor,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn initWithDevice_labelsDescriptor( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, labels_descriptor: &MPSCNNLossDataDescriptor, ) -> Retained<Self>
MPSNeuralNetwork only.Set labels (aka targets, ground truth) for the MPSCNNLossLabels object.
The labels and weights data are copied into internal storage. The computed loss can either be a scalar value (in batch mode, a single value per image in a batch) or it can be one value per feature channel. Thus, the size of the loss image must either match the size of the input source image or be {1, 1, 1}, which results in a scalar value. In this convinience initializer, the assumed size of the loss image is {1, 1, 1}.
Parameter device: Device the state resources will be created on.
Parameter labelsDescriptor: Describes the labels data. This includes:
- The per-element labels data. The data must be in floating point format.
- Data layout of labels data. See MPSImage.h for more information.
- Size of labels data: (width, height, feature channels}.
- Optionally, row bytes of labels data.
- Optionally, slice bytes of labels data.
Sourcepub unsafe fn initWithDevice_lossImageSize_labelsDescriptor_weightsDescriptor(
this: Allocated<Self>,
device: &ProtocolObject<dyn MTLDevice>,
loss_image_size: MTLSize,
labels_descriptor: &MPSCNNLossDataDescriptor,
weights_descriptor: Option<&MPSCNNLossDataDescriptor>,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn initWithDevice_lossImageSize_labelsDescriptor_weightsDescriptor( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, loss_image_size: MTLSize, labels_descriptor: &MPSCNNLossDataDescriptor, weights_descriptor: Option<&MPSCNNLossDataDescriptor>, ) -> Retained<Self>
MPSNeuralNetwork only.Set labels (aka targets, ground truth) and weights for the MPSCNNLossLabels object. Weights are optional.
The labels and weights data are copied into internal storage.
Parameter device: Device the state resources will be created on.
Parameter lossImageSize: The size of the resulting loss image: { width, height, featureChannels }.
The computed loss can either be a scalar value (in batch mode, a single
value per image in a batch) or it can be one value per feature channel.
Thus, the size of the loss image must either match the size of the input
source image or be {1, 1, 1}, which results in a scalar value.
Parameter labelsDescriptor: Describes the labels data. This includes:
- The per-element labels data. The data must be in floating point format.
- Data layout of labels data. See MPSImage.h for more information.
- Size of labels data: (width, height, feature channels}.
- Optionally, row bytes of labels data.
- Optionally, slice bytes of labels data.
Parameter weightsDescriptor: Describes the weights data. This includes:
- The per-element weights data. The data must be in floating point format.
- Data layout of weights data. See MPSImage.h for more information.
- Size of weights data: (width, height, feature channels}.
- Optionally, row bytes of weights data.
- Optionally, slice bytes of weights data. This parameter is optional. If you are using a single weight, please use the weight property of the MPSCNNLossDescriptor object.
Sourcepub unsafe fn initWithDevice_lossImageSize_labelsImage_weightsImage(
this: Allocated<Self>,
device: &ProtocolObject<dyn MTLDevice>,
loss_image_size: MTLSize,
labels_image: &MPSImage,
weights_image: Option<&MPSImage>,
) -> Retained<Self>
Available on crate features MPSNeuralNetwork and MPSImage only.
pub unsafe fn initWithDevice_lossImageSize_labelsImage_weightsImage( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, loss_image_size: MTLSize, labels_image: &MPSImage, weights_image: Option<&MPSImage>, ) -> Retained<Self>
MPSNeuralNetwork and MPSImage only.Set labels (aka targets, ground truth) and weights for the MPSCNNLossLabels object. Weights are optional.
The labels and weights images are retained - it is the users responsibility to make sure that they contain the right data when the loss filter is run on the device.
Parameter device: Device the state resources will be created on.
Parameter lossImageSize: The size of the resulting loss image: { width, height, featureChannels }.
The computed loss can either be a scalar value (in batch mode, a single
value per image in a batch) or it can be one value per feature channel.
Thus, the size of the loss image must either match the size of the input
source image or be {1, 1, 1}, which results in a scalar value.
Parameter labelsImage: Describes the labels data.
Parameter weightsImage: Describes the weights data.
This parameter is optional. If you are using a single weight, please use the
weight property of the MPSCNNLossDescriptor object.
Sourcepub unsafe fn lossImage(&self) -> Retained<MPSImage>
Available on crate features MPSNeuralNetwork and MPSImage only.
pub unsafe fn lossImage(&self) -> Retained<MPSImage>
MPSNeuralNetwork and MPSImage only.Loss image accessor method.
Returns: An autoreleased MPSImage object, containing the loss data. The loss data is populated in the -encode call, thus the contents are undefined until you -encode the filter.
In order to guarantee that the image is correctly synchronized for CPU side access, it is the application’s responsibility to call the [gradientState synchronizeOnCommandBuffer:] method before accessing the data in the image.
Sourcepub unsafe fn labelsImage(&self) -> Retained<MPSImage>
Available on crate features MPSNeuralNetwork and MPSImage only.
pub unsafe fn labelsImage(&self) -> Retained<MPSImage>
MPSNeuralNetwork and MPSImage only.Labels image accessor method.
Returns: An autoreleased MPSImage object, containing the labels data. The labels data is populated in the -initWithDevice call.
In order to guarantee that the image is correctly synchronized for CPU side access, it is the application’s responsibility to call the [gradientState synchronizeOnCommandBuffer:] method before accessing the data in the image.
Sourcepub unsafe fn weightsImage(&self) -> Retained<MPSImage>
Available on crate features MPSNeuralNetwork and MPSImage only.
pub unsafe fn weightsImage(&self) -> Retained<MPSImage>
MPSNeuralNetwork and MPSImage only.Weights image accessor method.
Returns: An autoreleased MPSImage object, containing the weights data. The weights data is populated in the -initWithDevice call.
In order to guarantee that the image is correctly synchronized for CPU side access, it is the application’s responsibility to call the [gradientState synchronizeOnCommandBuffer:] method before accessing the data in the image.
Source§impl MPSCNNLossLabels
Methods declared on superclass MPSState.
impl MPSCNNLossLabels
Methods declared on superclass MPSState.
Sourcepub unsafe fn temporaryStateWithCommandBuffer_bufferSize(
cmd_buf: &ProtocolObject<dyn MTLCommandBuffer>,
buffer_size: usize,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn temporaryStateWithCommandBuffer_bufferSize( cmd_buf: &ProtocolObject<dyn MTLCommandBuffer>, buffer_size: usize, ) -> Retained<Self>
MPSNeuralNetwork only.Create a MPSState holding a temporary MTLBuffer
Parameter cmdBuf: The command buffer against which the temporary resource is allocated
Parameter bufferSize: The size of the buffer in bytes
Sourcepub unsafe fn temporaryStateWithCommandBuffer_textureDescriptor(
cmd_buf: &ProtocolObject<dyn MTLCommandBuffer>,
descriptor: &MTLTextureDescriptor,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn temporaryStateWithCommandBuffer_textureDescriptor( cmd_buf: &ProtocolObject<dyn MTLCommandBuffer>, descriptor: &MTLTextureDescriptor, ) -> Retained<Self>
MPSNeuralNetwork only.Create a MPSState holding a temporary MTLTexture
Parameter cmdBuf: The command buffer against which the temporary resource is allocated
Parameter descriptor: A descriptor for the new temporary texture
Sourcepub unsafe fn temporaryStateWithCommandBuffer(
cmd_buf: &ProtocolObject<dyn MTLCommandBuffer>,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn temporaryStateWithCommandBuffer( cmd_buf: &ProtocolObject<dyn MTLCommandBuffer>, ) -> Retained<Self>
MPSNeuralNetwork only.Create a new autoreleased temporary state object without underlying resource
Parameter cmdBuf: The command buffer with which the temporary resource is associated
pub unsafe fn initWithDevice_bufferSize( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, buffer_size: usize, ) -> Retained<Self>
MPSNeuralNetwork only.pub unsafe fn initWithDevice_textureDescriptor( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, descriptor: &MTLTextureDescriptor, ) -> Retained<Self>
MPSNeuralNetwork only.Sourcepub unsafe fn initWithResource(
this: Allocated<Self>,
resource: Option<&ProtocolObject<dyn MTLResource>>,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn initWithResource( this: Allocated<Self>, resource: Option<&ProtocolObject<dyn MTLResource>>, ) -> Retained<Self>
MPSNeuralNetwork only.Create a MPSState with a non-temporary MTLResource
Parameter resource: A MTLBuffer or MTLTexture. May be nil.
§Safety
resourcemay need to be synchronized.resourcemay be unretained, you must ensure it is kept alive while in use.
Sourcepub unsafe fn initWithDevice_resourceList(
this: Allocated<Self>,
device: &ProtocolObject<dyn MTLDevice>,
resource_list: &MPSStateResourceList,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn initWithDevice_resourceList( this: Allocated<Self>, device: &ProtocolObject<dyn MTLDevice>, resource_list: &MPSStateResourceList, ) -> Retained<Self>
MPSNeuralNetwork only.Initialize a non-temporary state to hold a number of textures and buffers
The allocation of each resource will be deferred until it is needed. This occurs when -resource or -resourceAtIndex: is called.
Parameter resourceList: The list of resources to create.
Sourcepub unsafe fn temporaryStateWithCommandBuffer_resourceList(
command_buffer: &ProtocolObject<dyn MTLCommandBuffer>,
resource_list: &MPSStateResourceList,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn temporaryStateWithCommandBuffer_resourceList( command_buffer: &ProtocolObject<dyn MTLCommandBuffer>, resource_list: &MPSStateResourceList, ) -> Retained<Self>
MPSNeuralNetwork only.Initialize a temporary state to hold a number of textures and buffers
The textures occur first in sequence
Sourcepub unsafe fn initWithResources(
this: Allocated<Self>,
resources: Option<&NSArray<ProtocolObject<dyn MTLResource>>>,
) -> Retained<Self>
Available on crate feature MPSNeuralNetwork only.
pub unsafe fn initWithResources( this: Allocated<Self>, resources: Option<&NSArray<ProtocolObject<dyn MTLResource>>>, ) -> Retained<Self>
MPSNeuralNetwork only.Create a state object with a list of MTLResources
Because MPS prefers deferred allocation of resources your application should use -initWithTextures:bufferSizes:bufferCount: whenever possible. This method is useful for cases when the MTLResources must be initialized by the CPU.
§Safety
resourcesgeneric may need to be synchronized.resourcesgeneric may be unretained, you must ensure it is kept alive while in use.
Methods from Deref<Target = MPSState>§
Sourcepub unsafe fn resourceCount(&self) -> NSUInteger
pub unsafe fn resourceCount(&self) -> NSUInteger
Return the number of MTLResource objects held by the state
Sourcepub unsafe fn resourceAtIndex_allocateMemory(
&self,
index: NSUInteger,
allocate_memory: bool,
) -> Option<Retained<ProtocolObject<dyn MTLResource>>>
pub unsafe fn resourceAtIndex_allocateMemory( &self, index: NSUInteger, allocate_memory: bool, ) -> Option<Retained<ProtocolObject<dyn MTLResource>>>
Get the MTLResource at the indicated index
By convention, except where otherwise documented, the MTLResources held by the MPSState are private to the MPSState object, owned by the MPSState subclass author. If the MPSState subclass author is MPS, then the identity (e.g. texture vs. buffer) and information contained in the resource should be considered implementation dependent. It may change by operating system version or device. If you are the author of the subclass then it is for your own use, and MPS will not look at it, except perhaps so as to pass it to a custom kernel. Otherwise, the method is made available to facilitate debugging and to allow you to write your own state objects. Provide accessors to read this information in a defined format.
Parameter index: The index of the MTLResource to retrieve
Parameter allocateMemory: It is very important to avoid allocating memory to hold
MTLResources until it is absolutely necessary, especially when working
with temporary MPSStates. When allocateMemory is set to NO and the
resource has not yet been allocated, nil will be returned instead.
If you just need information about the resource such as buffer size
or MTLTexture properties, but not the resource itself, please use
-bufferSizeAtIndex: or -textureInfoAtIndex: instead, as these will
not force the creation of the MTLResource.
pub unsafe fn readCount(&self) -> NSUInteger
Sourcepub unsafe fn setReadCount(&self, read_count: NSUInteger)
pub unsafe fn setReadCount(&self, read_count: NSUInteger)
Setter for readCount.
pub unsafe fn isTemporary(&self) -> bool
Sourcepub unsafe fn label(&self) -> Option<Retained<NSString>>
pub unsafe fn label(&self) -> Option<Retained<NSString>>
A string to help identify this object.
Sourcepub unsafe fn bufferSizeAtIndex(&self, index: NSUInteger) -> NSUInteger
pub unsafe fn bufferSizeAtIndex(&self, index: NSUInteger) -> NSUInteger
Return the buffer size of the MTLBuffer at index or 0 if it is not a MTLBuffer
Does not force allocation of the MTLResource
Sourcepub unsafe fn textureInfoAtIndex(
&self,
index: NSUInteger,
) -> MPSStateTextureInfo
pub unsafe fn textureInfoAtIndex( &self, index: NSUInteger, ) -> MPSStateTextureInfo
Return the texture size {width,height,depth} or {0,0,0} if it is not a MTLTexture
Does not force allocation of the MTLResource
Sourcepub unsafe fn resourceTypeAtIndex(
&self,
index: NSUInteger,
) -> MPSStateResourceType
pub unsafe fn resourceTypeAtIndex( &self, index: NSUInteger, ) -> MPSStateResourceType
Return YES if the resource at index is a buffer
Does not force allocation of the MTLResource
Sourcepub unsafe fn synchronizeOnCommandBuffer(
&self,
command_buffer: &ProtocolObject<dyn MTLCommandBuffer>,
)
pub unsafe fn synchronizeOnCommandBuffer( &self, command_buffer: &ProtocolObject<dyn MTLCommandBuffer>, )
Flush any copy of MTLResources held by the state from the device’s caches, and invalidate any CPU caches if needed.
This will call [id <MTLBlitEncoder
synchronizeResource: ] on the state’s MTLResources. This is necessary for all MTLStorageModeManaged resources. For other resources, including temporary resources (these are all MTLStorageModePrivate), nothing is done.
Parameter commandBuffer: The commandbuffer on which to synchronize
Sourcepub unsafe fn resourceSize(&self) -> NSUInteger
pub unsafe fn resourceSize(&self) -> NSUInteger
Get the number of bytes used to allocate underyling MTLResources
This is the size of the backing store of underlying MTLResources. It does not include all storage used by the object, for example the storage used to hold the MPSState instantiation and MTLTexture or MTLBuffer is not included. It only measures the size of the allocation used to hold the texels in the texture or bytes in the buffer. This value is subject to change between different devices and operating systems.
Except when -initWithResource: is used, most MPSStates are allocated without a backing store. The backing store is allocated lazily when it is needed, typically when the .texture property is called. Consequently, in most cases, it should be inexpensive to make a MPSImage to see how much memory it will need, and release it if it is too large.
This method may fail in certain circumstances, such as when the MPSImage is created with -initWithTexture:featureChannels:, in which case 0 will be returned.
Sourcepub unsafe fn destinationImageDescriptorForSourceImages_sourceStates_forKernel_suggestedDescriptor(
&self,
source_images: &NSArray<MPSImage>,
source_states: Option<&NSArray<MPSState>>,
kernel: &MPSKernel,
in_descriptor: &MPSImageDescriptor,
) -> Retained<MPSImageDescriptor>
Available on crate features MPSImage and MPSKernel only.
pub unsafe fn destinationImageDescriptorForSourceImages_sourceStates_forKernel_suggestedDescriptor( &self, source_images: &NSArray<MPSImage>, source_states: Option<&NSArray<MPSState>>, kernel: &MPSKernel, in_descriptor: &MPSImageDescriptor, ) -> Retained<MPSImageDescriptor>
MPSImage and MPSKernel only.Determine padding and sizing of result images
A MPSState has the opportunity to reconfigure the MPSImageDescriptor used to create the filter result state and set the MPSKernel.offset to the correct value. By default, the MPSState does not modify the descriptor.
There is a order of operations defined for who may update the descriptor:
- Default padding code runs based on the MPSNNPaddingMethod in the MPSCNNKernel.padding. This creates the descriptor and picks a starting value for the MPSCNNKernel.offset.
- MPSStates are called in order to apply this function and update the offset.
- The MPSNNPadding custom padding method of the same name is called.
Some code that may prove helpful:
const int centeringPolicy = 0; // When kernelSize is even: 0 pad bottom right. 1 pad top left. Centers the kernel for even sized kernels.
typedef enum Style{
StyleValidOnly = -1,
StyleSame = 0,
StyleFull = 1
}Style;
// Typical destination size in one dimension for forward filters (most filters)
static int DestSize( int sourceSize, int stride, int filterWindowSize, Style style ){
sourceSize += style * (filterWindowSize - 1); // adjust how many pixels we are allowed to read
return (sourceSize + stride - 1) / stride; // sourceSize / stride, round up
}
// Typical destination size in one dimension for reverse filters (e.g. convolution transpose)
static int DestSizeReverse( int sourceSize, int stride, int filterWindowSize, Style style ){
return (sourceSize-1) * stride + // center tap for the last N-1 results. Take stride into account
1 + // center tap for the first result
style * (filterWindowSize-1); // add or subtract (or ignore) the filter extent
}
// Find the MPSOffset in one dimension
static int Offset( int sourceSize, int stride, int filterWindowSize, Style style ){
// The correction needed to adjust from position of left edge to center per MPSOffset definition
int correction = filterWindowSize / 2;
// exit if all we want is to start consuming pixels at the left edge of the image.
if( 0 )
return correction;
// Center the area consumed in the source image:
// Calculate the size of the destination image
int destSize = DestSize( sourceSize, stride, filterWindowSize, style ); // use DestSizeReverse here instead as appropriate
// calculate extent of pixels we need to read in source to populate the destination
int readSize = (destSize-1) * stride + filterWindowSize;
// calculate number of missing pixels in source
int extraSize = readSize - sourceSize;
// number of missing pixels on left side
int leftExtraPixels = (extraSize + centeringPolicy) / 2;
// account for the fact that the offset is based on the center pixel, not the left edge
return correction - leftExtraPixels;
}Parameter sourceImages: The list of source images to be used
Parameter sourceStates: The list of source states to be used
Parameter kernel: The MPSKernel the padding method will be applied to. Set the kernel.offset
Parameter inDescriptor: MPS will prepare a starting guess based on the padding policy (exclusive of
MPSNNPaddingMethodCustom) set for the object. You should adjust the offset
and image size accordingly. It is on an autoreleasepool.
Returns: The MPSImageDescriptor to use to make a MPSImage to capture the results from the filter. The MPSImageDescriptor is assumed to be on an autoreleasepool. Your method must also set the kernel.offset property.
Sourcepub unsafe fn resource(
&self,
) -> Option<Retained<ProtocolObject<dyn MTLResource>>>
👎Deprecated
pub unsafe fn resource( &self, ) -> Option<Retained<ProtocolObject<dyn MTLResource>>>
Get the private MTLResource underlying the MPSState
When the state is not directly initialized with a MTLResource, the actuall MTLResource creation is deferred. Especially with temporary resources, it is important to delay this creation as late as possible to avoid increasing the memory footprint. The memory is returned for reuse when the readCount = 0. Calling the -resource method will force the resource to be allocated, so you should not use it lightly, for purposes such as finding the MTLPixelFormat of a texture in the state.
By convention, except where otherwise documented, the MTLResources held by the MPSState are private to the MPSState object, owned by the MPSState subclass author. If the MPSState subclass author is MPS, then the identity (e.g. texture vs. buffer) and information contained in the resource should be considered implementation dependent. It may change by operating system version or device. If you are the author of the subclass then it is for your own use, and MPS will not look at it, except perhaps so as to pass it to a custom kernel. Otherwise, the method is made available to facilitate debugging and to allow you to write your own state objects.
Methods from Deref<Target = NSObject>§
Sourcepub fn doesNotRecognizeSelector(&self, sel: Sel) -> !
pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !
Handle messages the object doesn’t recognize.
See Apple’s documentation for details.
Methods from Deref<Target = AnyObject>§
Sourcepub fn class(&self) -> &'static AnyClass
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());Sourcepub unsafe fn get_ivar<T>(&self, name: &str) -> &Twhere
T: Encode,
👎Deprecated: this is difficult to use correctly, use Ivar::load instead.
pub unsafe fn get_ivar<T>(&self, name: &str) -> &Twhere
T: Encode,
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.
Sourcepub fn downcast_ref<T>(&self) -> Option<&T>where
T: DowncastTarget,
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`
}
}Trait Implementations§
Source§impl AsRef<AnyObject> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl AsRef<AnyObject> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl AsRef<MPSCNNLossLabels> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl AsRef<MPSCNNLossLabels> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl AsRef<MPSState> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl AsRef<MPSState> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl AsRef<NSObject> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl AsRef<NSObject> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl Borrow<AnyObject> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Borrow<AnyObject> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl Borrow<MPSState> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Borrow<MPSState> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl Borrow<NSObject> for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Borrow<NSObject> for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl ClassType for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl ClassType for MPSCNNLossLabels
MPSNeuralNetwork only.Source§const NAME: &'static str = "MPSCNNLossLabels"
const NAME: &'static str = "MPSCNNLossLabels"
Source§type ThreadKind = <<MPSCNNLossLabels as ClassType>::Super as ClassType>::ThreadKind
type ThreadKind = <<MPSCNNLossLabels as ClassType>::Super as ClassType>::ThreadKind
Source§impl Debug for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Debug for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl Deref for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Deref for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl Hash for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Hash for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl Message for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl Message for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl NSObjectProtocol for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl NSObjectProtocol for MPSCNNLossLabels
MPSNeuralNetwork only.Source§fn isEqual(&self, other: Option<&AnyObject>) -> bool
fn isEqual(&self, other: Option<&AnyObject>) -> bool
Source§fn hash(&self) -> usize
fn hash(&self) -> usize
Source§fn isKindOfClass(&self, cls: &AnyClass) -> bool
fn isKindOfClass(&self, cls: &AnyClass) -> bool
Source§fn is_kind_of<T>(&self) -> bool
fn is_kind_of<T>(&self) -> bool
isKindOfClass directly, or cast your objects with AnyObject::downcast_refSource§fn isMemberOfClass(&self, cls: &AnyClass) -> bool
fn isMemberOfClass(&self, cls: &AnyClass) -> bool
Source§fn respondsToSelector(&self, aSelector: Sel) -> bool
fn respondsToSelector(&self, aSelector: Sel) -> bool
Source§fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool
fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool
Source§fn debugDescription(&self) -> Retained<NSObject>
fn debugDescription(&self) -> Retained<NSObject>
Source§impl PartialEq for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl PartialEq for MPSCNNLossLabels
MPSNeuralNetwork only.Source§impl RefEncode for MPSCNNLossLabels
Available on crate feature MPSNeuralNetwork only.
impl RefEncode for MPSCNNLossLabels
MPSNeuralNetwork only.Source§const ENCODING_REF: Encoding = <MPSState as ::objc2::RefEncode>::ENCODING_REF
const ENCODING_REF: Encoding = <MPSState as ::objc2::RefEncode>::ENCODING_REF
impl DowncastTarget for MPSCNNLossLabels
MPSNeuralNetwork only.impl Eq for MPSCNNLossLabels
MPSNeuralNetwork only.