Adafruit_CircuitPython_Bitm.../adafruit_bitmapsaver.py
2019-07-25 14:09:07 -04:00

111 lines
3.9 KiB
Python

# The MIT License (MIT)
#
# Copyright (c) 2019 Dave Astels for Adafruit Industries
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
"""
`adafruit_bitmapsaver`
================================================================================
Save a displayio.Bitmap (and associated displayio.Palette) into a BMP file.
* Author(s): Dave Astels
Implementation Notes
--------------------
**Hardware:**
**Software and Dependencies:**
* Adafruit CircuitPython firmware for the supported boards:
https://github.com/adafruit/circuitpython/releases
"""
# imports
import struct
from displayio import Bitmap, Palette
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BitmapSaver.git"
#pylint:disable=line-too-long,broad-except,redefined-outer-name
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, bitmap):
output_file.write(struct.pack('<I', 40))
output_file.write(struct.pack('<I', bitmap.width))
output_file.write(struct.pack('<I', bitmap.height))
output_file.write(struct.pack('<H', 1))
output_file.write(struct.pack('<H', 24))
output_file.write(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
def _bytes_per_row(bitmap):
pixel_bytes = 3 * bitmap.width
padding_bytes = (4 - (pixel_bytes % 4)) % 4
return pixel_bytes + padding_bytes
def _write_pixels(output_file, bitmap, palette):
row_buffer = bytearray(_bytes_per_row(bitmap))
for y in range(bitmap.height, 0, -1):
buffer_index = 0
for x in range(bitmap.width):
pixel = bitmap[x, y-1]
color = palette[pixel]
for _ in range(3):
row_buffer[buffer_index] = color & 0xFF
color >>= 8
buffer_index += 1
output_file.write(row_buffer)
def save_bitmap(bitmap, palette, file_or_filename):
"""Save a bitmap (using an associated palette) to a 24 bit per pixel BMP file.
:param bitmap: the displayio.Bitmap to save
:param palette: the displayio.Palette to use for looking up colors in the bitmap
"""
if not isinstance(bitmap, Bitmap):
raise ValueError('bitmap')
if not isinstance(palette, Palette):
raise ValueError('palette')
try:
if isinstance(file_or_filename, str):
output_file = open(file_or_filename, 'wb')
else:
output_file = file_or_filename
filesize = 54 + bitmap.height * _bytes_per_row(bitmap)
_write_bmp_header(output_file, filesize)
_write_dib_header(output_file, bitmap)
_write_pixels(output_file, bitmap, palette)
except Exception:
raise
else:
output_file.close()