Package apple.metalperformanceshaders

Class MPSImageConvolution

  • All Implemented Interfaces:
    NSCoding, NSCopying, NSSecureCoding, NSObject
    public class MPSImageConvolution
extends MPSUnaryImageKernel
    MPSImageConvolution The MPSImageConvolution convolves an image with given filter of odd width and height. The center of the kernel aligns with the MPSImageConvolution.offset. That is, the position of the top left corner of the area covered by the kernel is given by MPSImageConvolution.offset - {kernel_width>>1, kernel_height>>1, 0} Optimized cases include 3x3,5x5,7x7,9x9,11x11, 1xN and Nx1. If a convolution kernel does not fall into one of these cases but is a rank-1 matrix (a.k.a. separable) then it will fall on an optimzied separable path. Other convolutions will execute with full MxN complexity. If there are multiple channels in the source image, each channel is processed independently. [@performance] Separable convolution filters may perform better when done in two passes. A convolution filter is separable if the ratio of filter values between all rows is constant over the whole row. For example, this edge detection filter: [@code] -1 0 1 -2 0 2 -1 0 1 [@endcode] can be separated into the product of two vectors: [@code] 1 2 x [-1 0 1] 1 [@endcode] and consequently can be done as two, one-dimensional convolution passes back to back on the same image. In this way, the number of multiplies (ignoring the fact that we could skip zeros here) is reduced from 3*3=9 to 3+3 = 6. There are similar savings for addition. For large filters, the savings can be profound.

    • Constructor Detail

      • MPSImageConvolution

        protected MPSImageConvolution​(org.moe.natj.general.Pointer peer)

    • Method Detail

      • accessInstanceVariablesDirectly

        public static boolean accessInstanceVariablesDirectly()

      • allocWithZone

        public static java.lang.Object allocWithZone​(org.moe.natj.general.ptr.VoidPtr zone)

      • automaticallyNotifiesObserversForKey

        public static boolean automaticallyNotifiesObserversForKey​(java.lang.String key)

      • cancelPreviousPerformRequestsWithTarget

        public static void cancelPreviousPerformRequestsWithTarget​(java.lang.Object aTarget)

      • cancelPreviousPerformRequestsWithTargetSelectorObject

        public static void cancelPreviousPerformRequestsWithTargetSelectorObject​(java.lang.Object aTarget,
                                                                         org.moe.natj.objc.SEL aSelector,
                                                                         java.lang.Object anArgument)

      • classFallbacksForKeyedArchiver

        public static NSArray<java.lang.String> classFallbacksForKeyedArchiver()

      • classForKeyedUnarchiver

        public static org.moe.natj.objc.Class classForKeyedUnarchiver()

      • debugDescription_static

        public static java.lang.String debugDescription_static()

      • description_static

        public static java.lang.String description_static()

      • hash_static

        public static long hash_static()

      • instanceMethodSignatureForSelector

        public static NSMethodSignature instanceMethodSignatureForSelector​(org.moe.natj.objc.SEL aSelector)

      • instancesRespondToSelector

        public static boolean instancesRespondToSelector​(org.moe.natj.objc.SEL aSelector)

      • isSubclassOfClass

        public static boolean isSubclassOfClass​(org.moe.natj.objc.Class aClass)

      • keyPathsForValuesAffectingValueForKey

        public static NSSet<java.lang.String> keyPathsForValuesAffectingValueForKey​(java.lang.String key)

      • new_objc

        public static java.lang.Object new_objc()

      • resolveClassMethod

        public static boolean resolveClassMethod​(org.moe.natj.objc.SEL sel)

      • resolveInstanceMethod

        public static boolean resolveInstanceMethod​(org.moe.natj.objc.SEL sel)

      • setVersion_static

        public static void setVersion_static​(long aVersion)

      • superclass_static

        public static org.moe.natj.objc.Class superclass_static()

      • version_static

        public static long version_static()

      • bias

        public float bias()
        [@property] bias The bias is a value to be added to convolved pixel before it is converted back to the storage format. It can be used to convert negative values into a representable range for a unsigned MTLPixelFormat. For example, many edge detection filters produce results in the range [-k,k]. By scaling the filter weights by 0.5/k and adding 0.5, the results will be in range [0,1] suitable for use with unorm formats. It can be used in combination with renormalization of the filter weights to do video ranging as part of the convolution effect. It can also just be used to increase the brightness of the image. Default value is 0.0f.

      • initWithDevice

        public MPSImageConvolution initWithDevice​(java.lang.Object device)
        Description copied from class: MPSUnaryImageKernel
        Standard init with default properties per filter type
        Overrides:
        initWithDevice in class MPSUnaryImageKernel
        Parameters:
        device - The device that the filter will be used on. May not be NULL.
        Returns:
        a pointer to the newly initialized object. This will fail, returning nil if the device is not supported. Devices must be MTLFeatureSet_iOS_GPUFamily2_v1 or later.

      • initWithDeviceKernelWidthKernelHeightWeights

        public MPSImageConvolution initWithDeviceKernelWidthKernelHeightWeights​(MTLDevice device,
                                                                        long kernelWidth,
                                                                        long kernelHeight,
                                                                        org.moe.natj.general.ptr.ConstFloatPtr kernelWeights)
        Initialize a convolution filter
        Parameters:
        device - The device the filter will run on
        kernelWidth - the width of the kernel
        kernelHeight - the height of the kernel
        kernelWeights - A pointer to an array of kernelWidth * kernelHeight values to be used as the kernel. These are in row major order.
        Returns:
        A valid MPSImageConvolution object or nil, if failure.

      • kernelHeight

        public long kernelHeight()
        [@property] kernelHeight The height of the filter window. Must be an odd number.

      • kernelWidth

        public long kernelWidth()
        [@property] kernelWidth The width of the filter window. Must be an odd number.

      • setBias

        public void setBias​(float value)
        [@property] bias The bias is a value to be added to convolved pixel before it is converted back to the storage format. It can be used to convert negative values into a representable range for a unsigned MTLPixelFormat. For example, many edge detection filters produce results in the range [-k,k]. By scaling the filter weights by 0.5/k and adding 0.5, the results will be in range [0,1] suitable for use with unorm formats. It can be used in combination with renormalization of the filter weights to do video ranging as part of the convolution effect. It can also just be used to increase the brightness of the image. Default value is 0.0f.

      • initWithCoderDevice

        public MPSImageConvolution initWithCoderDevice​(NSCoder aDecoder,
                                               java.lang.Object device)
        NSSecureCoding compatability While the standard NSSecureCoding/NSCoding method -initWithCoder: should work, since the file can't know which device your data is allocated on, we have to guess and may guess incorrectly. To avoid that problem, use initWithCoder:device instead.
        Overrides:
        initWithCoderDevice in class MPSUnaryImageKernel
        Parameters:
        aDecoder - The NSCoder subclass with your serialized MPSKernel
        device - The MTLDevice on which to make the MPSKernel
        Returns:
        A new MPSKernel object, or nil if failure.

      • supportsSecureCoding

        public static boolean supportsSecureCoding()

      • _supportsSecureCoding

        public boolean _supportsSecureCoding()
        Description copied from interface: NSSecureCoding
        This property must return YES on all classes that allow secure coding. Subclasses of classes that adopt NSSecureCoding and override initWithCoder: must also override this method and return YES. The Secure Coding Guide should be consulted when writing methods that decode data.
        Specified by:
        _supportsSecureCoding in interface NSSecureCoding
        Overrides:
        _supportsSecureCoding in class MPSUnaryImageKernel