Draw glyphs on a pygame surface using fonttools and SVG.

font_svg_pygame.py

from collections import defaultdict
import io
import sys

import numpy as np
from scipy.special import comb
import pygame

from fontTools.pens.svgPathPen import (SVGPathPen, )
from fontTools.pens.basePen import (BasePen, )
from fontTools.ttLib import TTFont


class PGMFont:
    WIDTH = 1280
    HEIGHT = 600
    def __init__(self, font):
        self.font = font
        self.units_per_em = self.font['head'].unitsPerEm
        self.ascent = self.font["hhea"].ascent
        self.descent = self.font["hhea"].descent
        self.cmap = self.font['cmap'].getBestCmap()
        self.glyph_set = self.font.getGlyphSet()
        self.kerning_pairs = self.prepare_kerning(self.font)

    def prepare_kerning(self, font: TTFont) -> dict:
        pairs = defaultdict(int)
        if not "kern" in self.font:
            return pairs
        for kern_table in self.font['kern'].kernTables:
            assert kern_table.version == 0, "kern table version other than 0 not supported"
            pairs.update(kern_table.kernTable)
        return pairs

    def prepare_window(self):
        self.screen = pygame.display.set_mode((self.WIDTH, self.HEIGHT))
        self.screen.fill((0, 0, 255))

    def create_svg_pair(self, text):
        """
        Create 2 SVG files, one for stroke, one for fill.
        """
        cmds_stroke = []
        cmds_fill = []

        pen = SVGPathPen(self.font.getGlyphSet())
        x0 = 0

        last_glyph = None
        for unicode in text:
            glyph_name = self.cmap.get(ord(unicode))
            if not glyph_name:
                glyph_name = ".notdef"

            glyph = self.glyph_set[glyph_name]
            pen = SVGPathPen(self.glyph_set)
            glyph.draw(pen)
            commands = pen.getCommands()

            x0 += self.kerning_pairs[(last_glyph, glyph_name)]
            s = '<g transform="translate(%d %d) scale(1 -1)"><path d="%s" %%s /></g>\n' % (
                x0,
                self.ascent,
                commands,
            )
            x0 += glyph.width
            cmds_stroke.append(s % 'stroke="#FFF" fill="none" stroke-width="50"')
            cmds_fill.append(s % 'stroke="none" fill="#F00"')

            last_glyph = glyph_name

        svg_stroke = "\n".join([
            """<?xml version="1.0" encoding="UTF-8"?>""",
            """<svg width="%d" height="%d" xmlns="http://www.w3.org/2000/svg">""" % (x0, self.ascent - self.descent),
            "\n".join(cmds_stroke) + "</svg>",
        ])
        svg_fill = "\n".join([
            """<?xml version="1.0" encoding="UTF-8"?>""",
            """<svg width="%d" height="%d" xmlns="http://www.w3.org/2000/svg">""" % (x0, self.ascent - self.descent),
            "\n".join(cmds_fill) + "</svg>",
        ])
        return (svg_stroke, svg_fill)

    def draw_text(self, surface, text):
        (svg_stroke, svg_fill) = self.create_svg_pair(text)
        img = pygame.image.load(io.BytesIO(svg_stroke.encode("utf-8")))
        surface.blit(img, (0, 0))
        img = pygame.image.load(io.BytesIO(svg_fill.encode("utf-8")))
        surface.blit(img, (0, 0))

    def draw_something(self):
        surface = pygame.Surface((self.units_per_em * 10, self.units_per_em * 2))
        surface.fill((0, 0, 0))
        self.draw_text(surface, "VADoO0-")
        scale = min((self.HEIGHT / surface.get_height(), self.WIDTH / surface.get_width()))
        surface = pygame.transform.smoothscale(
            surface,
            (int(surface.get_width() * scale), int(surface.get_height() * scale)),
        )
        self.screen.blit(surface, (0, 0))

    def run(self):
        clock = pygame.time.Clock()
        do_run = True
        while do_run:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    do_run = False
                    break
            self.draw_something()
            pygame.display.flip()


if "__main__" == __name__:
    f = TTFont("/usr/share/fonts/truetype/liberation2/LiberationSans-Regular.ttf")
    pygame.init()
    pgm = PGMFont(f)
    pgm.prepare_window()
    pgm.run()
    pygame.quit()