Unicode boxes on a terminal

Unicode boxes on a terminal#

Licence CC BY-NC-ND, Thierry Parmentelat

Unicode comes with a few characters that can be used to draw squares or rectangles on the terminal

See e.g. this page for a list

https://en.wikipedia.org/wiki/Box-drawing_character

NOTE these examples may look a little awkward on the notebook, but will look fine when run on a terminal, provided that it uses a fixed-width font, something that any decent terminal does

a first example#

print ("wide box")
print ("\u250f\u2501\u2513")   # 3 odd characters
print ("\u2503 \u2503")        # 2 oddities + 1 space in the middle
print ("\u2517\u2501\u251b")   # 3 odd characters

wide box
┏━┓
┃ ┃
┗━┛

for creating this example, all I had to do was to find the codepoint for each of the characters that I need, and insert them in a Python string using the ‘\unnnn’ notation, where nnnn is the 4-digit hexadecimal codepoint.

# an example with one single character 
"\u250f"

'┏'

adding color#

optionnally, like we’ve seen for the evaluation, we can draw color on the terminal with the colorama library; note that it is useful mostly for Windows terminals (as other devices has standard ways to do color).

from colorama import Fore, Style

def red_text(text):
    return f"{Fore.RED}{text}{Style.RESET_ALL}"

"hello " + red_text("to the") + " world"

'hello \x1b[31mto the\x1b[0m world'

well here again, the output is awkward on the notebook, never mind…

putting it together#

print ("thin box")
print ("\u250c\u2500\u2510")
print ("\u2502 \u2502")
print ("\u2514\u2500\u2518")

thin box
┌─┐
│ │
└─┘

print ("wide connectable box")
print ("\u254b\u2501\u2513")
print ("\u2503 \u2523")
print ("\u2517\u2501\u251b")

wide connectable box
╋━┓
┃ ┣
┗━┛

# of course we could also do this
thin_box = """\u250f\u2501\u2513
\u2503 \u2503
\u2517\u2501\u251b"""
print(thin_box)

┏━┓
┃ ┃
┗━┛

print(red_text(thin_box))

┏━┓
┃ ┃
┗━┛

# or that
double_box = """\u2554\u2566\u2557
\u2560\u256c\u2563
\u255a\u2569\u255d"""
print(double_box)

╔╦╗
╠╬╣
╚╩╝

print(red_text(double_box))

╔╦╗
╠╬╣
╚╩╝

well, you get the picture..

assignment#

v0#

We want to be able to write sentences like this

from boxes import Box0

b0 = Box0(8, 4)
print(b0.box())

┏━━━━━━┓
┃      ┃
┃      ┃
┗━━━━━━┛

v1#

or even better: add style

from boxes import Box1

b11 = Box1(4, 3, style='thin')
print(b11.box())

┌──┐
│  │
└──┘

and then color

b12 = Box1(10, 4, style='thin', color=Fore.BLUE)
print(b12.box())

┌────────┐
│        │
│        │
└────────┘

v2#

or better still

from boxes import Box2

b21 = Box2(4, 3, style='thin')
print(b21)

┌──┐
│  │
└──┘

b22 = Box2(10, 4, color=Fore.BLUE, style='thin')
print(b22)

┌────────┐
│        │
│        │
└────────┘

assignment - if you’re done#

a few suggestions about how to improve

  • accept for the width and height: either an int (like before) or a list of integers so we can build grids instead of boxes

    b = Grid(10, [2, 2])

  • make it reconnectable ? needs some thinking though ;-)

  • etc…

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