mpsimagetypes.h(3) [mojave man page]

MPSImageTypes.h(3)					 MetalPerformanceShaders.framework					MPSImageTypes.h(3)

NAME

       MPSImageTypes.h

SYNOPSIS

       #import <MPSCore/MPSCoreTypes.h>

   Typedefs
       typedef enum MPSAlphaType MPSAlphaType

   Enumerations
       enum MPSAlphaType { MPSAlphaTypeNonPremultiplied, MPSAlphaTypeAlphaIsOne, MPSAlphaTypePremultiplied }

Typedef Documentation
   typedef enum MPSAlphaType
	    MPSAlphaType"

Enumeration Type Documentation
   enum MPSAlphaType
       Premultiplication description for the color channels of a texture  Some image data is premultiplied. That is to say that the color channels
       are stored instead as color * alpha. This is an optimization for image compositing (alpha blending), but it can get in the way of most
       other image filters, especially those that apply non-linear affects like the MPSImageParametricCurveTransform multidimensional lookup
       tables, and functions like convolution or resampling filters that look at adjacent pixels, where the alpha may not be the same.

       Some basic conversion cases:
	   source			       destination			   operation
	   ------			       -----------			   ---------
	   MPSAlphaTypeNonPremultiplied        MPSAlphaTypeNonPremultiplied	   <none>
	   MPSAlphaTypeNonPremultiplied        MPSAlphaTypeAlphaIsOne		   composite with opaque background color
	   MPSAlphaTypeNonPremultiplied        MPSAlphaTypePremultiplied	   multiply color channels by alpha
	   MPSAlphaTypeAlphaIsOne	       MPSAlphaTypeNonPremultiplied	   set alpha to 1
	   MPSAlphaTypeAlphaIsOne	       MPSAlphaTypeAlphaIsOne		   set alpha to 1
	   MPSAlphaTypeAlphaIsOne	       MPSAlphaTypePremultiplied	   set alpha to 1
	   MPSAlphaTypePremultiplied	       MPSAlphaTypeNonPremultiplied	   divide color channels by alpha
	   MPSAlphaTypePremultiplied	       MPSAlphaTypeAlphaIsOne		   composite with opaque background color
	   MPSAlphaTypePremultiplied	       MPSAlphaTypePremultiplied	   <none>

	       Color space conversion operations require the format to be either MPSPixelAlpha_NonPremultiplied or
	       MPSPixelAlpha_AlphaIsOne to work correctly. A number of MPSKernels have similar requirements. If
	       premultiplied data is provided or requested, extra operations will be added to the conversion to
	       ensure correct operation. Fully opaque images should use MPSAlphaTypeAlphaIsOne.

       MPSAlphaTypeNonPremultiplied Image is not premultiplied by alpha. Alpha is not guaranteed to be 1. (kCGImageAlphaFirst/Last)
       MPSAlphaTypeAlphaIsOne Alpha is guaranteed to be 1, even if it is not encoded as 1 or not encoded at all. (kCGImageAlphaNoneSkipFirst/Last,
       kCGImageAlphaNone)  MPSAlphaTypePremultiplied Image is premultiplied by alpha. Alpha is not guaranteed to be 1.
       (kCGImageAlphaPremultipliedFirst/Last)

       Enumerator

       MPSAlphaTypeNonPremultiplied

       MPSAlphaTypeAlphaIsOne

       MPSAlphaTypePremultiplied

Author
       Generated automatically by Doxygen for MetalPerformanceShaders.framework from the source code.

Version MetalPerformanceShaders-100				  Thu Feb 8 2018						MPSImageTypes.h(3)

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MPSImageConversion(3)					 MetalPerformanceShaders.framework				     MPSImageConversion(3)

NAME

       MPSImageConversion

SYNOPSIS

       #import <MPSImageConversion.h>

       Inherits MPSUnaryImageKernel.

   Instance Methods
       (nonnull instancetype) - initWithDevice:srcAlpha:destAlpha:backgroundColor:conversionInfo:

   Properties
       MPSAlphaType sourceAlpha
       MPSAlphaType destinationAlpha

   Additional Inherited Members
Detailed Description
       MPSImageConversions.h  MetalPerformanceShaders.framework

       Copyright:
	   Copyright (c) 2015 Apple Inc. All rights reserved.  MetalPerformanceShaders conversion filters  MPS_CLASS_AVAILABLE_STARTING

       The MPSImageConversion filter performs a conversion from source to destination

Method Documentation
   - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >) device(MPSAlphaType) srcAlpha(MPSAlphaType) destAlpha(nullable CGFloat *)
       backgroundColor(nullable CGColorConversionInfoRef) conversionInfo
       Create a converter that can convert texture colorspace, alpha and texture format  Create a converter that can convert texture colorspace,
       alpha and MTLPixelFormat. Optimized cases exist for NULL color space converter and no alpha conversion.

       Parameters:
	   device The device the filter will run on
	   srcAlpha The alpha encoding for the source texture
	   destAlpha The alpha encoding for the destination texture
	   backgroundColor An array of CGFloats giving the background color to use when flattening an image. The color is in the source
	   colorspace. The length of the array is the number of color channels in the src colorspace. If NULL, use {0}.
	   conversionInfo The colorspace conversion to use. May be NULL, indicating no color space conversions need to be done.

       Returns:
	   An initialized MPSImageConversion object.

Property Documentation
   - destinationAlpha [read],  [nonatomic],  [assign]
       Premultiplication description for the destinationAlpha texture  Colorspace conversion operations produce non-premultiplied data. Use this
       property to tag cases where premultiplied results are required. If MPSPixelAlpha_AlphaIsOne is used, the alpha channel will be set to 1.
       Default: MPSPixelAlpha_AlphaIsOne

   - sourceAlpha [read],  [nonatomic],	[assign]
       Premultiplication description for the source texture  Most colorspace conversion operations can not work directly on premultiplied data.
       Use this property to tag premultiplied data so that the source texture can be unpremultiplied prior to application of these transforms.
       Default: MPSPixelAlpha_AlphaIsOne

Author
       Generated automatically by Doxygen for MetalPerformanceShaders.framework from the source code.

Version MetalPerformanceShaders-100				  Thu Feb 8 2018					     MPSImageConversion(3)

Linux and UNIX Man Pages

mpsimagetypes.h(3) [mojave man page]

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