Class: AVCaptureVideoPreviewLayer
Overview
AVCaptureVideoPreviewLayer is a subclass of CALayer that you use to display video as it is being captured by an input device.
Instance Attribute Summary (collapse)
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- connection
readonly
The capture connection describing the AVCaptureInputPort to which the preview layer is connected.
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- session
The capture session instance being previewed.
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- videoGravity
Indicates how the video is displayed within a player layer’s bounds rect.
Attributes inherited from CALayer
#actions, #anchorPoint, #anchorPointZ, #backgroundColor, #backgroundFilters, #borderColor, #borderWidth, #bounds, #compositingFilter, #contents, #contentsCenter, #contentsGravity, #contentsRect, #contentsScale, #cornerRadius, #delegate, #doubleSided, #drawsAsynchronously, #edgeAntialiasingMask, #filters, #frame, #geometryFlipped, #hidden, #magnificationFilter, #mask, #masksToBounds, #minificationFilter, #minificationFilterBias, #name, #needsDisplayOnBoundsChange, #opacity, #opaque, #position, #rasterizationScale, #shadowColor, #shadowOffset, #shadowOpacity, #shadowPath, #shadowRadius, #shouldRasterize, #style, #sublayerTransform, #sublayers, #superlayer, #transform, #visibleRect, #zPosition
Class Method Summary (collapse)
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+ layerWithSession:
Returns a preview layer initialized with a given capture session.
Instance Method Summary (collapse)
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- captureDevicePointOfInterestForPoint:
Converts a point from layer coordinates to the coordinate space of the capture device.
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- initWithSession:
Initializes a preview layer with a given capture session.
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- pointForCaptureDevicePointOfInterest:
Converts a point from the coordinate space of the capture device to the coordinate space of the layer.
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- transformedMetadataObjectForMetadataObject:
Converts a metadata object’s visual properties to layer coordinates.
Methods inherited from CALayer
#actionForKey:, #addAnimation:forKey:, #addSublayer:, #affineTransform, #animationForKey:, #animationKeys, #containsPoint:, #contentsAreFlipped, #convertPoint:fromLayer:, #convertPoint:toLayer:, #convertRect:fromLayer:, #convertRect:toLayer:, #convertTime:fromLayer:, #convertTime:toLayer:, defaultActionForKey:, defaultValueForKey:, #display, #displayIfNeeded, #drawInContext:, #hitTest:, #init, #initWithLayer:, #insertSublayer:above:, #insertSublayer:atIndex:, #insertSublayer:below:, layer, #layoutIfNeeded, #layoutSublayers, #modelLayer, #needsDisplay, needsDisplayForKey:, #needsLayout, #preferredFrameSize, #presentationLayer, #removeAllAnimations, #removeAnimationForKey:, #removeFromSuperlayer, #renderInContext:, #replaceSublayer:with:, #scrollPoint:, #scrollRectToVisible:, #setAffineTransform:, #setNeedsDisplay, #setNeedsDisplayInRect:, #setNeedsLayout, #shouldArchiveValueForKey:
Methods inherited from NSObject
#!, #!=, #!~, #, #==, #===, #=~, #Rational, #__callee__, #__method__, #__send__, #__type__, `, alloc, allocWithZone:, #autoContentAccessingProxy, autoload, autoload?, autorelease_pool, #awakeAfterUsingCoder:, binding, block_given?, caller, cancelPreviousPerformRequestsWithTarget:, cancelPreviousPerformRequestsWithTarget:selector:object:, catch, class, classFallbacksForKeyedArchiver, #classForCoder, #classForKeyedArchiver, classForKeyedUnarchiver, #clone, conformsToProtocol:, #copy, copyWithZone:, #dealloc, #define_singleton_method, description, display, #doesNotRecognizeSelector:, #dup, #enum_for, #eql?, #equal?, #extend, fail, #finalize, format, #forwardInvocation:, #forwardingTargetForSelector:, framework, #freeze, #frozen?, getpass, gets, global_variables, #init, initialize, #initialize_clone, #initialize_copy, #initialize_dup, #inspect, instanceMethodForSelector:, instanceMethodSignatureForSelector:, #instance_eval, #instance_exec, #instance_of?, #instance_variable_defined?, #instance_variable_get, #instance_variable_set, #instance_variables, instancesRespondToSelector:, isSubclassOfClass:, #is_a?, iterator?, #kind_of?, lambda, load, load_bridge_support_file, load_plist, local_variables, loop, #method, #methodForSelector:, #methodSignatureForSelector:, #methods, #mutableCopy, mutableCopyWithZone:, new, #nil?, open, p, #performSelector:onThread:withObject:waitUntilDone:, #performSelector:onThread:withObject:waitUntilDone:modes:, #performSelector:withObject:afterDelay:, #performSelector:withObject:afterDelay:inModes:, #performSelectorInBackground:withObject:, #performSelectorOnMainThread:withObject:waitUntilDone:, #performSelectorOnMainThread:withObject:waitUntilDone:modes:, print, printf, #private_methods, proc, #protected_methods, #public_method, #public_methods, #public_send, putc, puts, raise, rand, readline, readlines, #replacementObjectForCoder:, #replacementObjectForKeyedArchiver:, require, resolveClassMethod:, resolveInstanceMethod:, #respond_to?, #respond_to_missing?, select, #send, setVersion:, #singleton_methods, sprintf, srand, superclass, #taint, #tainted?, #tap, test, throw, #to_plist, #to_s, trace_var, trap, #trust, #untaint, untrace_var, #untrust, #untrusted?, version
Constructor Details
This class inherits a constructor from NSObject
Dynamic Method Handling
This class handles dynamic methods through the method_missing method in the class NSObject
Instance Attribute Details
- (AVCaptureConnection) connection (readonly)
The capture connection describing the AVCaptureInputPort to which the preview layer is connected. (read-only) If you invoke initWithSession:, layerWithSession:, or setSession: (see session) with a valid AVCaptureSession instance, a connection is formed to the first eligible video AVCaptureInput object. If the preview layer is detached from a session, the connection property becomes nil.
- (AVCaptureSession) session
The capture session instance being previewed.
- (String) videoGravity
Indicates how the video is displayed within a player layer’s bounds rect. Options are AVLayerVideoGravityResizeAspect, AVLayerVideoGravityResizeAspectFill and AVLayerVideoGravityResize. The default is AVLayerVideoGravityResizeAspect.This property is animatable.
Class Method Details
+ (Object) layerWithSession(session)
Returns a preview layer initialized with a given capture session.
Instance Method Details
- (CGPoint) captureDevicePointOfInterestForPoint(pointInLayer)
Converts a point from layer coordinates to the coordinate space of the capture device. The coordinates in the point structure returned by this method are in the range 0.0 to 1.0. The point (0.0, 0.0) corresponds to the top left corner of the unrotated picture and the point (1.0, 1.0) represents the bottom right corner of the unrotated picture. The conversion performed by this method takes the layer’s frame size and the receiver’s videoGravity property into consideration.
- (Object) initWithSession(session)
Initializes a preview layer with a given capture session.
- (CGPoint) pointForCaptureDevicePointOfInterest(captureDevicePointOfInterest)
Converts a point from the coordinate space of the capture device to the coordinate space of the layer. The conversion performed by this method takes the layer’s frame size and the receiver’s videoGravity property into consideration.
- (AVMetadataObject) transformedMetadataObjectForMetadataObject(metadataObject)
Converts a metadata object’s visual properties to layer coordinates. An AVMetadataObject’s bounds may be expressed as a rect, where an origin point of (0.0, 0.0) represents the top-left corner of an unrotated picture and (1.0, 1.0) represents the bottom-right corner of an unrotated picture. Face metadata objects also express a yaw and roll angle with respect to an unrotated picture. This method converts all of the metadata object’s visual properties to the coordinate space of the receiver, taking into account orientation, mirroring, layer bounds and videoGravity.