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-Thu2Jul 13 2017             MPSImageTypes.h(3)


Mac OS X 10.12.6 - Generated Mon Oct 30 18:31:45 CDT 2017