The method of converting pictures into ASCII characters

overview

Character painting is a combination of a series of characters. We can regard characters as relatively large pixels. One character can represent one color (let’s understand it this way for now). The more types of characters, the more colors that can be represented. The picture will also be more layered.

Here comes the problem, we want to convert a color picture, so many colors, how to correspond to monochrome characters? Here we will introduce the concept of gray value.

Gray value: refers to the color depth of the midpoint of the black and white image, generally ranging from 0 to 255, white is 255, and black is 0, so black and white images are also called grayscale images

We can map a pixel's RGB value to a grayscale value using the grayscale formula:

gray ＝ 0.2126 * r + 0.7152 * g + 0.0722 * b

Implementation

from PIL import Image
import argparse

# 命令行输入参数处理
parser = argparse.ArgumentParser()

# 输入文件， 输出文件， 输出字符画宽， 输出字符画高
parser.add_argument('file')
parser.add_argument('-o', '--output')
# 不同尺寸的图片转ASCII时，需要根据实际情况调整默认宽与高
parser.add_argument('--width', type=int, default=150)
parser.add_argument('--height', type=int, default=80)

# 获取参数
args = parser.parse_args()

IMG = args.file
WIDTH = args.width
HEIGHT = args.height
OUTPUT = args.output

ascii_char = list("$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"^`'. ")


# 将256灰度映射到70个字符上
def get_char(r, g, b, alpha=256):
    if alpha == 0:
        return ' '
    length = len(ascii_char)
    gray = int(0.2126 * r + 0.7152 * g + 0.0722 * b)

    unit = (256.0 + 1)/length
    return ascii_char[int(gray/unit)]


if __name__ == "__main__":
    im = Image.open(IMG)
    im = im.resize((WIDTH, HEIGHT), Image.NEAREST)

    txt = ''

    for i in range(HEIGHT):
        for j in range(WIDTH):
            txt += get_char(*im.getpixel((j,i)))
        txt += '\n'

    print(txt)

    # 字符画输出到文件
    if OUTPUT:
        with open(OUTPUT, 'w') as f:
            f.write(txt)
    else:
        with open('output.txt', 'w') as f:
            f.write(txt)

Operation example

How to use the script:

# 安装环境
pip install Pillow

# photo.png 是图片文件，建议使用png背景透明的图片
python3 ascii.py photo.png

1. Flying Paddle Logo

output:

                      `..`^.               ."...
                      .cmdd'              .~0qp^
                       wppqO'            `'pqppZ.
                     .'ikZw.              ..abO      .......  .`    ,.."`.'' .^  .Il...^..
            .......  ...'' .   .......   ..  ^.'      .pppppppp.` .+pb . qp`}dm"cmmdpqkp"
            `~qqpI ':mqqpp-"'. . .pppn...qqObq; ..   `......pq'`.'^dk'. :'Zqqqmqm.""^"hq..
          ...bppz .^obkqwOwd  .'.bqdb'. obbpbwbb..        'bp?Cqaqk*.^   ^":dqm..bqq.bbq'.
          .'Ydpd,  '.' ."Xmpq .'pdpp  ''`''.^kpqa.        mqd}mmQ\'`"....<aZkqm.' Cabb).'
          .<qdw>'       .'qqq` .pwp^.       ..dqw`        dq.okk'..   ..iwb.?hwmdqh0I` .
''   ..  . qbpJ' ..   ... pdZ..dppk ..   .. .^dpq.     '.kZ_. oph ... ^' '...  bdn....'''.
'.''''''''hbdb'  ......:cqdqQ.wppp"'.......`bmppx^      Op0^  .>aqw01>. ?qwwwqqdqkppqqpq..
'npqqqqqqqqpw..pqqqqqqqqqdb].-mqd,^pqqqqqqqpqmq!.    '.+wq^^  ...'mhdq^..' 'rnnbpnxv<.
^bkkkkkhbpppm"obakkkkkkkZ!:^'pddu`QbkkkkkkkhQ^^".      ZmY''...  '..'. ..'`Jqp'bpn.db)''.
`.   ...kbq#`'...  ...... '.0ppd'........    '.       'qpbdpwwqqqwwwww^.[pbq]``bpu.'Xqdw.
       Jdpw..              ?mpq>'                     ..":!!!!lll!!iii^^!!^.. .L0f..  '>..
     ..obq..             .:wpw[                        '...............'`.. '  .^   ...'
    .'pbpb.'            ^`pdpw'                       .
  ..'wdbb..             'xdpm.'                      ..                                  .
  '.fqwp`.             .;qpq)                        ..                                  .
  ',{}}? .            ..)})1".                       '' .  ..      ...`'        . ..

2. TF
   

output:

                     ;/\  \\+'
                 ,(\  \\||||>
             i/tt//\  \\|||||(((_.
         `]fffttt//\  \\|||||(((()){:
     .;jjfffffttt//\  \\|||||(((())))))i'
  "(jjjjjfffffttt//\  \\|||||(((())))))111{I
  }jjjjjjfffffttt//\  \\|||||(((())))))1111{
$ }jjjjjjfffff}{t//\  \\|||||((>)))))))1111{
$ }jjjjjjft:   {t//\  \\|||||((   .})))1111{
$ }jjjj['      {t//\  \\|||||((       l1111{
$ 1t"          {t//\  \\|||||(((<        .?{
$              {t//\  \\|||||(((())]"
               {t//\  \\|||||(((())))
               {t//\  \\|||||(((())))
               {t//\  \\|||||(((())))
               {t//\  \\|||||((  :[))
               {t//\  \\|||||((
               {t//\  \\|||||((
               {t//\  \\|||||((
               {t//\  \\|||||((
               {t//\  \\|||||((
               ;)//\  \\|||||)<
                   .[//\  \\|)^
                       ;  ~'

output:

CLLLLLLL1                                 CLLLLLL 0{
0OOOOOOO(                                 0OOOOOO O{
   _O                                     0O      O{
   _O   >OOO   OiOOO`  QOOO   ,OOO)  OOOO 0O      O{  xOOO  OO  LO  1O
   _O  "OL;OO  OO}+OO nO:^OO .OO;JO` OOOQ 0O      O{ JOrIOO CO  OO  OO
   _O  OO   O` Or  OO OO  i> OO   OO OO   0OOOOO  O{ OO   O] O  OO/ O0
   _O  OOXXXO{ Oj  OO :OOr   OO   0O OO   0Ovvvv  O{ O1   OO O-+OCO O`
   _O  OOQQQQ) Oj  OO  'QOO0 OO   LO OO   0O      O{ O_   OO OOOU O'O
   _O  OO      Oj  OO 1?  CO OO   OO OO   0O      O{ OO   O1 nOO  OQO
   _O  uOx  O  Oj  OO OO  OO >Ox IO? OO   0O      O{ OO' CO   OO  OOO
   _O   COOOQ  Oj  OO  OOOO<  cOOOO  OO   0O      O{  OOOO:   OO  ,O.