Contents

vImagePremultiplyData_PlanarF(_:_:_:_:)

Transforms a 32-bit planar buffer from nonpremultiplied alpha format to premultiplied alpha format.

Declaration

func vImagePremultiplyData_PlanarF(_ src: UnsafePointer<vImage_Buffer>, _ alpha: UnsafePointer<vImage_Buffer>, _ dest: UnsafePointer<vImage_Buffer>, _ flags: vImage_Flags) -> vImage_Error

Parameters

  • src:

    The source vImage buffer.

  • alpha:

    The vImage buffer that provides the source alpha.

  • dest:

    A pointer to the destination vImage buffer structure. You’re responsible for filling out the Height, Width, and Rowbytes fields of this structure, and for allocating a data buffer of the appropriate size. On return, the data buffer this structure points to contains the destination image data. When you no longer need the data buffer, deallocate the memory to prevent memory leaks.

  • flags:

    The options to use when performing the operation. If your code implements its own tiling or its own multithreading, pass Kvimagedonottile; otherwise, pass Kvimagenoflags.

Return Value

kvImageNoError; otherwise, one of the error codes in Data Types and Constants.

Discussion

This function multiplies color channels by the alpha channel using the following code:

uint8_t destColor = (src * alpha + 127) / 255;

See Also

Related Documentation

Converting from unpremultiplied to premultiplied format