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bit_transpose(input: _typing.ReadableBuffer, output: _typing.WriteableBuffer, width: int = 8) → _typing.WriteableBuffer¶
“Transpose” a buffer by assembling each output byte with bits taken from each of
widthdifferent input bytes.
This can be useful to convert a sequence of pixel values into a single stream of bytes suitable for sending via a parallel conversion method.
The number of bytes in the input buffer must be a multiple of the width, and the width can be any value from 2 to 8. If the width is fewer than 8, then the remaining (less significant) bits of the output are set to zero.
stride = len(input)//width. Then the first byte is made out of the most significant bits of
[input, input[stride], input[2*stride], ...]. The second byte is made out of the second bits, and so on until the 8th output byte which is made of the first bits of
input, input[1+stride, input[2*stride], ...].
The required output buffer size is
len(input) * 8 // width.
Returns the output buffer.