illustration.py

"""
MINERAL ILLUSTRATOR
A tool to reduce the colors of a photo to a given colorpalette.

Please provide the following inputs in your directory:

1) A photo named input.png. It is recommended to scale it down to a low resolution e.g. 300x200

2) A csv-table colors.csb where you list the desired colors. The following convention is used:

#ff444b cherry_red - f
#40cc9a darkgreen HB f
#389075 darkgreen 4H f

So the scheme is:
[html-color] [crayon] [pencil] [comment]#
[crayon]: freely chosen name of the colored pencil
[pencil]: the values -,4H, H, B, 4B are accepted, where "-" means that the crayon wasnt shaded by a pencil.
[comment]: you may add anything. I used it to distinguish between how firmly i applied pressure with the crayon.
"""

import numpy as np
import matplotlib.pyplot as plt
import csv
from PIL import Image

def html_to_rgb(html_colors):
    """
    Turns the list of html strings into a list of tuple with 3 integers
    """
    rgb_list = []
    for color in html_colors:
        color = color.lstrip('#')
        rgb = (int(color[0:2], 16),int(color[2:4], 16),int(color[4:6], 16))        
        rgb_colors.append(rgb)
    
    return rgb_list


#-----READING THE PALETTE-----
raw=[] #In this list, the entire row will be stored
html_colors=[] #In this list, only the color will be stored

with open("colors.csv", 'r') as file:
    reader = csv.reader(file, delimiter=' ')

    for row in reader:
        raw.append(row)
        html_colors.append(row[0])

RGB_palette = html_to_rgb(html_colors)

R,G,B=[],[],[]
for c in palette_RGB:
    R.append(c[0])
    G.append(c[1])
    B.append(c[2])


#-----READING THE IMAGE-----
image = Image.open('input.png')
photo = image.convert('RGB')
photo = np.array(photo)
#print("Image shape:", photo.shape)


#-----POSTERIZE-----
#Initialize the arrays:
painting = np.zeros(photo.shape,dtype=int) #output image
hue = np.zeros(photo.shape,dtype=int) #crayons-only decomposition
pencil = np.zeros((len(photo),len(photo[0])),dtype=int)  #pencil-only decomposition
numbers=np.zeros((len(photo),len(photo[0])),dtype=int) #the "primary keys" like in paint by numbers
used_colors=[] #To generate a list of the colors needed for the painting

for i in range(len(photo)):
    for j in range(len(photo[0])):
        (R_real,G_real,B_real)=photo[i][j]
        #find the best match
        k=0
        k_ideal=0
        delta=999999999
        while k<len(raw):
            if ((R[k]-R_real)**2)+((G[k]-G_real)**2)+((B[k]-B_real)**2)<delta:
               delta=((R[k]-R_real)**2)+((G[k]-G_real)**2)+((B[k]-B_real)**2)
               k_ideal=k
            k+=1
        painting[i][j][0]=int(R[k_ideal])
        painting[i][j][1]=int(G[k_ideal])
        painting[i][j][2]=int(B[k_ideal])

        #find k_hue,which is the index of the color we get when stripping the pencil shading from the best matching color
        for n in range(max(0,k_ideal-10),min(len(raw),k_ideal+10)):
            if raw[n][1]==raw[k_ideal][1] and raw[n][2]=="-" and raw[n][3]==raw[k_ideal][3]:
                k_hue=n
        hue[i][j][0]=int(R[k_hue])
        hue[i][j][1]=int(G[k_hue])
        hue[i][j][2]=int(B[k_hue])
        
        pencil[i][j]={"-":0,"4H":1,"H":2,"B":3,"4B":4}[raw[k_ideal][2]] #<--if other pencil hardnesses desired, change here
        numbers[i][j]=k_ideal
        used_colors.append(k_ideal)
        #print(i,j)

#remove redundancies and sort
used_colors=set(used_colors) 
used_colors=list(used_colors)
used_colors=sorted(used_colors)

#----OUTPUT----
#Display list of needed colors
for k in used_colors:
    print(k,"...\t",raw[k][1],raw[k][3])

#Display results
plt.figure()
plt.imshow(pencil,cmap="binary")
plt.figure()
plt.imshow(hue)
plt.imshow(numbers, alpha=0)
plt.figure()
plt.imshow(painting)
plt.show()