| m.bmp |
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image-processing.py
# Translate list of bytes to number
def bytes_to_number(L):
x = 0
for b in reversed(L):
x = x * 256 + b
return x
# Read Image
def read_image(file_name):
with open(file_name, 'rb') as f:
code = list(f.read()) # list of file bytes
offset = bytes_to_number(code[10:14]) # where colors data begins
w = bytes_to_number(code[18:22]) # decode width
h = bytes_to_number(code[22:26]) # decode height
line_size = (3 * w + 3) // 4 * 4 # line size in bytes, must be aligned by 4 bytes
return (code, w, h, line_size, offset)
# Put one new color in image bytes
# color is in (b, g, r) format
def put_pixel(image, x, y, color):
offset = image[4] + image[3] * (image[2] - 1 - y) + x * 3
image[0][offset:offset + 3] = color
# Get color of a pixel with (x, y) coordinates
# color is in (b, g, r) format
def get_pixel(image, x, y):
offset = image[4] + image[3] * (image[2] - 1 - y) + x * 3
return image[0][offset:offset + 3]
im = read_image('sample.bmp')
w = im[1]
h = im[2]
# Image processing
for y in range(h):
for x in range(w):
c = get_pixel(im, x, y)
# ... doing something with color 'c'
put_pixel(im, x, y, new_color)
# Save result
with open('result.bmp', 'wb') as f:
f.write(bytes(im[0]))
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