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@VolkerH
Forked from wshanshan/asciiart.py
Created April 12, 2019 00:09
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Create ASCII art from an image
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")
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