"""

Adapted from "https://github.com/adafruit/Adafruit_CircuitPython_BitmapSaver.git"

"""

import gc

import struct

from abstract_plotter import AbstractPlotter

def _write_bmp_header(output_file, filesize):

output_file.write(bytes("BM", "ascii"))

output_file.write(struct.pack("<I", filesize))

output_file.write(b"\00\x00")

output_file.write(b"\00\x00")

output_file.write(struct.pack("<I", 54))

def _write_dib_header(output_file, width, height):

output_file.write(struct.pack("<I", 40))

output_file.write(struct.pack("<I", width))

output_file.write(struct.pack("<I", height))

output_file.write(struct.pack("<H", 1))

output_file.write(struct.pack("<H", 24))

for _ in range(24):

output_file.write(b"\x00")

def _bytes_per_row(source_width):

pixel_bytes = 3 * source_width

padding_bytes = (4 - (pixel_bytes % 4)) % 4

return pixel_bytes + padding_bytes

def rgb565_to_bgr_tuple(pixel565):

pass

def _write_pixels(output_file, plotter: AbstractPlotter):

width = plotter.width()

height = plotter.height()

row_buffer = bytearray(_bytes_per_row(width))

for y in range(height, 0, -1):

buffer_index = 0

for i in range(width):

try:

pixel = plotter.get_pixel(i, y-1)

except Exception as e:

print(i, y)

raise e

for b in reversed(pixel):

row_buffer[buffer_index] = b & 0xFF

buffer_index += 1

output_file.write(row_buffer)

gc.collect()

def save_pixels(filename, plotter: AbstractPlotter):

"""Save pixels to a 24 bit per pixel BMP file.

:param filename: the file name to save to

:param plotter: plotter that created the image to save

"""

width = plotter.width()

height = plotter.height()

filesize = 54 + height * _bytes_per_row(width)

with open(filename, "wb") as output_file:

_write_bmp_header(output_file, filesize)

_write_dib_header(output_file, width, height)

_write_pixels(output_file, plotter)