Converts an RGBA8888 image to an RGBA5551 image with dithering.
- iOS 7.0+
- macOS 10.9+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
A pointer to a vImage buffer structure that contains the source image whose data you want to convert.
A pointer to a vImage buffer data structure. You're responsible for filling out the
rowfields 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, you must deallocate the memory.
A pointer to a region of memory that vImage can use as a scratch space for storing temporary data.
The options to use when performing the operation. If you plan to perform your own tiling or use multithreading, pass
Image Do Not Tile
This function is similar to
v, except the result is dithered instead of rounded to the nearest RGBA5551 value. It should provide more accurate overall color reproduction and less banding in low-frequency regions of the image.
This function supports the following dithering options:
Image Convert _Dither Ordered
Precomputed blue noise is added to the image before the values are rounded to the destination format. The offset into the blue noise is randomized per call to avoid visible artifacts if you do your own tiling or call the function on sequential frames of video.
Image Convert _Dither Ordered Reproducible
Precomputed blue noise is added to the image before the values are rounded to the destination format. The offset into the blue noise is the same for every call to allow users to get reproducible results.
This function can work in place provided the following are true:
For each buffer,
buf, that overlaps with
buf->datais equal to
Bytes >= dest->row Bytes
If an overlapping buffer has a different
kvis also passed in the flags.
Image Do Not Tile