Create ASCII art from an image

asciiart.py

from PIL import Image, ImageDraw, ImageFont
from colour import Color
import numpy as np

# The function convert an image to ascii art
# f: Input filename
# SC: the horizontal pixel sampling rate. It should be between 0(exclusive) and 1(inclusive). The larger the number, the more details in the output. 
#   If you want the ascii art output be the same size as input, use ~ 1/ font size width. 
# GCF: >0. It's an image tuning factor. If GCF>1, the image will look brighter; if 0<GCF<1, the image will look darker.
# out_f: output filename
# color1, color2, bgcolor: follow W3C color naming https://www.w3.org/TR/css3-color/#svg-color
#
# Copyright 2017, Shanshan Wang, MIT license


def asciiart(in_f, SC, GCF,  out_f, color1='black', color2='blue', bgcolor='white'):

    # The array of ascii symbols from white to black
    chars = np.asarray(list(' .,:irs?@9B&#'))

    # Load the fonts and then get the the height and width of a typical symbol 
    # You can use different fonts here
    font = ImageFont.load_default()
    letter_width = font.getsize("x")[0]
    letter_height = font.getsize("x")[1]

    WCF = letter_height/letter_width

    #open the input file
    img = Image.open(in_f)

    #Based on the desired output image size, calculate how many ascii letters are needed on the width and height
    widthByLetter=round(img.size[0]*SC*WCF)
    heightByLetter = round(img.size[1]*SC)
    S = (widthByLetter, heightByLetter)

    #Resize the image based on the symbol width and height
    img = img.resize(S)
    
    #Get the RGB color values of each sampled pixel point and convert them to graycolor using the average method.
    # Refer to https://www.johndcook.com/blog/2009/08/24/algorithms-convert-color-grayscale/ to know about the algorithm
    img = np.sum(np.asarray(img), axis=2)
    
    # Normalize the results, enhance and reduce the brightness contrast. 
    # Map grayscale values to bins of symbols
    img -= img.min()
    img = (1.0 - img/img.max())**GCF*(chars.size-1)
    
    # Generate the ascii art symbols 
    lines = ("\n".join( ("".join(r) for r in chars[img.astype(int)]) )).split("\n")

    # Create gradient color bins
    nbins = len(lines)
    colorRange =list(Color(color1).range_to(Color(color2), nbins))

    #Create an image object, set its width and height
    newImg_width= letter_width *widthByLetter
    newImg_height = letter_height * heightByLetter
    newImg = Image.new("RGBA", (newImg_width, newImg_height), bgcolor)
    draw = ImageDraw.Draw(newImg)

    # Print symbols to image
    leftpadding=0
    y = 0
    lineIdx=0
    for line in lines:
        color = colorRange[lineIdx]
        lineIdx +=1

        draw.text((leftpadding, y), line, color.hex, font=font)
        y += letter_height

    # Save the image file
    newImg.save(out_f)

# main() 
if __name__=='__main__':

    inputf = "IQaH96.jpeg"  # Input image file name

    SC = 0.1    # pixel sampling rate in width
    GCF= 2      # contrast adjustment

    asciiart(inputf, SC, GCF, "results.png")   #default color, black to blue
    asciiart(inputf, SC, GCF, "results_pink.png","blue","pink")

Sample output

Hi, in new version of Pillow we dont have getsize for symbol instead of we have getbbox but after changing your code is not working correctly of you have a time please update it. thanks

Hello, as @vyacheslavparkhomenko pointed out this no longer works due to Pillow removing FreeTypeFont.getsize(). Moreover, ImageFont's default font is no longer monospaced, and thus deforms the image. I created this fork: https://gist.github.com/geconf/9c44d8de2d37408b08aca9202c041c6a and wrote a fix