Kern proof generator with Drawbot and drawbotgrid

kernproof.py

from drawBotGrid import BaselineGrid, columnBaselineGridTextBox
import os
import datetime
import itertools
import unicodedata

# When you add more fonts, it stacks the strings for each
# weight to enable easy comparisons. 
fonts = ('Helvetica Neue Thin', 'Helvetica Neue', 'Helvetica Neue Bold')
#fonts = ('Helvetica Neue Thin', 'Helvetica Neue')
fontnumber = len(fonts)
familyname = 'Helvetica Neue'

# These are the strings fo characters that will be mashed together
# to generate the kerning strings. You do have to take care with
# escaping certain characters.
ucchars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZÆĐÞƠƯ'
lcchars = 'abcdefghijklmnopqrstuvwxyzßďľðơư'
numchars = '0123456789'
punctchars = '.,:;-_¿?¡!\/()[]{}‹›@\'‘’*&§¶°†‡'
ucpunctchars = '¡¿·•\/-(){}[]‹›@'
mathchars = '∕+−×÷=≠><≥≤±≈~¬^%∅∞'
currchars = '€¢¤$₫₴₤₺₱₽₹£₩¥'
topleftclash = 'FĽƠTƯVWYďđfíĭǐîïīĩĵľſťấẩếềểốồổ7'
toprightclash = 'TVWYằàðhĭǐîïìīĩ'
bottomleftclash = 'ĘỊĮQąęịįjļḷțṯỵ'
bottomrightclash = 'ỊJgịjļpţṯ'
# For ligatures you store each combination of letters that
# generates a ligature and then toggle them with OT features 
#ss01right = ('AI', 'AV', 'AW', 'FI', 'FO', 'LA', 'LD', 'LE', 'LI', 'LL', 'LO', 'LR', 'RI', 'FA', 'TE', 'TO', 'UE', 'VE', 'WE', 'WR', 'QU', 'RA', 'RE', 'RO', 'RU')
#ss01left = ('OR', 'OU')

# Template characters to use as context for strings
uc1 = 'H'
uc2 = 'O'
lc1 = 'n'
lc2 = 'o'
num1 = '0'


# This function helps with making the lines of strings
# have a specific amount of *words* per line.
def wrap_by_word(s, n):
    '''returns a string where \\n is inserted between every n words'''
    a = s.split()
    ret = ''
    for i in range(0, len(a), n):
        ret += ' '.join(a[i:i+n]) + '\n'
    return ret


# This function generates the kern strings by mashing up
# groups of characters. If you give it only one list, it
# will mash it up against itself but will avoid repeating
# them, so thge further you progress the fewer combinations
# you will see. If you give it two separate strings to
# mash up, it will do all against all, every
# combination (mathematical product).
def makeKern (section, linelen, *args):
    kernstring = ''
    if len(args) == 1:
        product = itertools.combinations_with_replacement(args[0], 2)
    elif len(args) == 2:
        product = itertools.product(args[0], args[1])
    else:
        print('Too many arguments!')
    for pair in product:
        strpair = ''.join(pair)
        if section == 'UC x LC' or section == 'LC x UC':
            makestr = f'{strpair}{lc1}{lc1}{lc1} '
        elif 'LIGA' in section:
            makestr = f'{uc1}{uc1}{strpair}{uc1}{uc1} '
        elif 'UC' in section:
            makestr = f'{uc1}{strpair}{uc1}{uc1}{strpair[::-1]}{uc1} '
        elif 'LC' in section:
            makestr = f'{lc1}{strpair}{lc1}{lc1}{strpair[::-1]}{lc1} '
        elif 'NUM' in section:
            makestr = f'{num1}{strpair}{num1}{num1}{strpair[::-1]}{num1} '
        elif 'CLASHERS' in section:
            makestr = f'{lc1}{lc1}{strpair}{lc1}{lc1} '
        else:
            makestr = f'{uc1}{strpair}{uc1}{uc1}{strpair[::-1]}{uc1} '
        kernstring += makestr
    kernstring = wrap_by_word(kernstring, linelen)
    return kernstring


# Make a footer per page. This comes from DJR's simple proof script.
def drawFooter(section):
    with savedState():
        folio = FormattedString(str(pageCount()),
            font='Courier',
            fontSize=9,
            lineHeight=9,
            align='right'
        )
        today = datetime.date.today()
        
        # assemble footer text
        footerText = f'{today} | {familyname} | {section}'
        
        # and display formatted string
        footer = FormattedString(footerText,
            font='Courier',
            fontSize=9,
            lineHeight=9
        )
        folio = FormattedString(str(pageCount()),
            font='Courier',
            fontSize=9,
            lineHeight=9,
            align="right"
        )
        textBox(footer, (40, 25, width()-25*2, 9))
        textBox(folio, (40, 25, width()-50*2, 9))


# This is the main function that draws the pages.
# It uses baseline grids and grid text boxes using
# Mathieu Reguer's drawbot grid. That means you can
# very easily switch to a multiple colum layout.
# And when stacking multiple lines, using the same
# baseline grid ensures it's all aligned and evenly linespaced.
# The name of the section is passed to the makeKern function
# Which has a few ifs to assign different control characters.
# The linelen argument is to assign independent linelengths to
# each section. Probably there's a way to automate that.
# args are the groups of character to mash up.
# For now kwargs takes an optional OT feature dict to toggle
# different features on and off.
def drawSection(section, linelen, *args, **kwargs):
    text = makeKern(section, linelen, *args)
    # I keep this print statement here in case I also want to
    # use the strings in a font editor.
    #print(text)
    while text:
        newPage('A4')
        drawFooter(section)
        fill(0)
        fontSize(15)
        lineHeight(20*fontnumber)
        
        # Parse the otfea dict to toggle feature per section
        if 'otfea' in kwargs:
            otfea = kwargs.get('otfea')
            openTypeFeatures(**otfea)
        else:
            openTypeFeatures(liga=False, kern=True)
        hyphenation(False)
        baselines = BaselineGrid.from_margins((0, -40, 0, -40), 5)
        # Uncomment the line below to see the baseline grid.
        #baselines.draw()
        
        # The code below is what draw the text to the page. Because
        # of how the while text loop works, I need to make a copy of
        # the text for each font I want to use, otherwise the text
        # gets used up by the first font, and the next font would use
        # the next line. I also use sa vertical shift to shift the text
        # boxes for each font after the first one.
        vshift = 0
        textprerun = text
        runs = 0
        for fi, f in enumerate(fonts, start=1):
            font(f)
            text = columnBaselineGridTextBox(text, (40, 40 - vshift, width()-80, height()-80), baselines, subdivisions=1, gutter=20, draw_grid=False)
            vshift = vshift + 20
            runs += 1
            if runs == fontnumber:
                continue
            else:
                text = textprerun


# Finally this is where you configure each section. If you
# want to have your own names for the sections, make sure to
# change the parsing logic on the makeKern function as well.
# The number is the amount of *words* per line for each section.
# You can give one or two groups of character to be mashed up.
# The otfea dict is optional and should be used to generate
# kern string involving glyphs that can only be accessed
# through OT features. 
drawSection('UC x UC', 4, ucchars)
drawSection('LC x LC', 4, lcchars)
drawSection('UC x LC', 6, ucchars, lcchars)
drawSection('LC x UC', 6, lcchars, ucchars)
drawSection('PUNCT x UC', 4, punctchars, ucchars)
# Uncomment the line below if you have UC punctuation in
# a case feature.
#drawSection('UCPUNCT x UC', 4, ucpunctchars, ucchars, otfea=dict(liga=False, case=True, kern=True))
drawSection('PUNCT x LC', 5, punctchars, lcchars)
drawSection('NUM x NUM', 6, numchars)
# Old-style numbers
#drawSection('ONUM x ONUM', 6, numchars, otfea=dict(liga=False, onum=True, kern=True))
drawSection('PUNCT x NUM', 5, punctchars, numchars)
#drawSection('PUNCT x ONUM', 5, punctchars, numchars, otfea=dict(liga=False, onum=True, kern=True))
drawSection('MATH x NUM', 5, mathchars, numchars)
#drawSection('MATH x ONUM', 5, mathchars, numchars, otfea=dict(liga=False, onum=True, kern=True))
drawSection('CURR x NUM', 5, currchars, numchars)
#drawSection('CURR x ONUM', 5, currchars, numchars, otfea=dict(liga=False, onum=True, kern=True))

# I made groups of glyphs that can normally clash so
# I can make sure they behave the way I want.
drawSection('TOP CLASHERS', 7, topleftclash, toprightclash)
drawSection('BOTTOM CLASHERS', 7, bottomleftclash, bottomrightclash)
# Examples for testing stylistic set ligatures
#drawSection('SS01LIGA x UC', 5, ss03right, ucchars, otfea=dict(liga=False, ss01=True, kern=True))
#drawSection('UC x SS01LIGA', 5, ucchars, ss03left, otfea=dict(liga=False, ss01=True, kern=True))

saveImage('kern-proof.pdf')

You need to have drawbotgrid installed in Drawbot. Instructions are in that repo.