RGB Int to RGB - Python

Question

How can I convert an RGB integer to the corresponding RGB tuple (R,G,B)? Seems simple enough, but I can't find anything on google.

I know that for every RGB (r,g,b) you have the integer n = r256^2 + g256 + b, how can I solve the reverse in Python, IE given an n, I need the r,g,b values.

Answer 1

From a RGB integer:

Blue =  RGBint mod 256
Green = RGBint / 256 mod 256
Red =   RGBint / 256 / 256 mod 256

This can be pretty simply implemented once you know how to get it. :)

Upd: Added python function. Not sure if there's a better way to do it, but this works on Python 3 and 2.4

def rgb_int2tuple(rgbint):
    return (rgbint // 256 // 256 % 256, rgbint // 256 % 256, rgbint % 256)

There's also an excellent solution that uses bitshifting and masking that's no doubt much faster that Nils Pipenbrinck posted.

Answer 2

There's probably a shorter way of doing this:

dec=10490586
hex="%06x" % dec
r=hex[:2]
g=hex[2:4]
b=hex[4:6]
rgb=(r,g,b)

EDIT: this is wrong - gives the answer in Hex, OP wanted int. EDIT2: refined to reduce misery and failure - needed '%06x' to ensure hex is always shown as six digits [thanks to Peter Hansen's comment].

Answer 3

I'm not a Python expert by all means, but as far as I know it has the same operators as C.

If so this should work and it should also be a lot quicker than using modulo and division.

Blue =  RGBint & 255
Green = (RGBint >> 8) & 255
Red =   (RGBint >> 16) & 255

What it does it to mask out the lowest byte in each case (the binary and with 255.. Equals to a 8 one bits). For the green and red component it does the same, but shifts the color-channel into the lowest byte first.

Answer 4

I assume you have a 32-bit integer containing the RGB values (e.g. ARGB). Then you can unpack the binary data using the struct module:

# Create an example value (this represents your 32-bit input integer in this example).
# The following line results in exampleRgbValue = binary 0x00FF77F0 (big endian)
exampleRgbValue = struct.pack(">I", 0x00FF77F0)

# Unpack the value (result is: a = 0, r = 255, g = 119, b = 240)
a, r, g, b = struct.unpack("BBBB", exampleRgbValue)

Answer 5

def unpack2rgb(intcol):
    tmp, blue= divmod(intcol, 256)
    tmp, green= divmod(tmp, 256)
    alpha, red= divmod(tmp, 256)
    return alpha, red, green, blue

If only the divmod(value, (divider1, divider2, divider3…)) suggestion was accepted, it would have simplified various time conversions too.