How to convert image to bmp565 format in Python?

Question

Python

Given:

• Picture. Without loss of generality, we will assume that it is in 24-bit bmp format - this can be exactly set in Paint. Less than 256 colors only
  
• Python 3 (Version 3 due to bytearray )
  
• Pillow (fork PIL)
  
• Method that gives a representation of the picture as bytes
  

What you need: get a bytearray, where each pixel is encoded using 2 bytes (in bmp565 format)

I think it's enough to find a solution for at least one point:

• graphics editor that saves in rgb565
  
• function to convert images byte by byte from any format to rgb565
  
• a way to convert using Pillow to rgb565 or another library capable of this
  

Answer 1

My version:

from PIL import Image
import numpy


def get_rgb565_bytes_from_image(filename):
    rgb888 = numpy.asarray(Image.open(filename))
    # check that image have 3 color components, each of 8 bits
    assert rgb888.shape[-1] == 3 and rgb888.dtype == numpy.uint8
    r5 = (rgb888[..., 0] >> 3 & 0x1f).astype(numpy.uint16)
    g6 = (rgb888[..., 1] >> 2 & 0x3f).astype(numpy.uint16)
    b5 = (rgb888[..., 2] >> 3 & 0x1f).astype(numpy.uint16)
    rgb565 = r5 << 11 | g6 << 5 | b5
    return rgb565.tobytes()