Some notes about using ctypes for accessing structured data

notes.py

import ctypes

class rgba(ctypes.Structure):
	_fields_ = (
		('r', ctypes.c_uint8),
		('g', ctypes.c_uint8),
		('b', ctypes.c_uint8),
		('a', ctypes.c_uint8),
	)





width = 3
height = 3

#Skapa 9 pixlar
data = (rgba * 9)(*(rgba(i, i+20, i+50, i+100) for i in range(9)))

data_ptr = ctypes.addressof(data)

print('Pixlarna finns på', hex(data_ptr))


pixels = (rgba*width*height).from_address(data_ptr)



x = 1
y = 2
p = pixels[y][x]
print(p.r, p.g, p.b, p.a)