[FIXED] How to give numbers a specific color and show it using PIL?

Issue

I've been working on a tile-based game and I wanted to know if there is a way I could make a map from just a file with numbers. I have a file "map.txt" within which are numbers representing each tile. These numbers(tiles) have different colors depending on the tile.

For Example:

0   0   1   1   1   1   0   1   2   2   2
0   1   2   2   1   1   0   0   0   1   0
0   0   1   1   1   1   0   1   2   2   2

0 - Black

1 - Yellow

2 - Green

I want to use PIL to make a map in which each tile gets represented as a pixel and save it as an image. I've seen it done using pygame but I want it using just PIL.

Thanks for the reply.

Solution

You can achieve that by using an image with mode P, i.e. an image using a palette.

The basic workflow then would be:

• Read text file, extract all numbers a continuous list.
• Determine width and height of map image from number of lines and total count of numbers.
• Create a new Image object with mode P using Image.new.
• Set image data from the obtained list of numbers using Image.putdata.
• Set up a proper palette for the desired number of colors, and apply that palette using Image.putpalette.

That'd be the whole code:

from PIL import Image

# Read map data from text file
with open('map.txt') as f:
    lines = f.readlines()

# Extract numbers from map data to continuous list of integers
imdata = [int(x) for line in lines for x in line if x.isdigit()]

# Get image dimensions
h = len(lines)
w = len(imdata) // h

# Create new image of correct size with mode 'P', set image data
img = Image.new('P', (w, h), 0)
img.putdata(imdata)

# Set up and apply palette data
img.putpalette([  0,   0,   0,          # Black
                255, 255,   0,          # Yellow
                  0, 255,   0])         # Green

# Save image
img.save('map.png')

And, that'd be the output image:

If you're willing to also use NumPy, the code could be shortened:

import numpy as np
from PIL import Image

# Extract numbers from map data to NumPy array
imdata = np.loadtxt('map.txt').astype(np.uint8)

# Create new image from NumPy array with mode 'P'
img = Image.fromarray(imdata, 'P')

# Set upand apply palette data
img.putpalette([  0,   0,   0,          # Black
                255, 255,   0,          # Yellow
                  0, 255,   0])         # Green

# Save image
img.save('map.png')

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System information
----------------------------------------
Platform:      Windows-10-10.0.16299-SP0
Python:        3.9.1
PyCharm:       2021.1.1
NumPy:         1.20.2
Pillow:        8.2.0
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Answered By - HansHirse