How to draw outline on the font(Pygame)

Question

How can I draw an outline on the font?
I want to use black font, but the background has to be blackish so it's hard to see the font.

I assume myfont.render doesn't support drawing outline on the font.

Is there other way?

Answer 1

Pygame doesn't support this out of the box, but one way to do it is render the text in the outline color and blit it to the result surface shifted multiple times, then render the text in the desired color on top of it.

pgzero uses this technique; a trimmed down version of its code is shown below:

import pygame

_circle_cache = {}
def _circlepoints(r):
    r = int(round(r))
    if r in _circle_cache:
        return _circle_cache[r]
    x, y, e = r, 0, 1 - r
    _circle_cache[r] = points = []
    while x >= y:
        points.append((x, y))
        y += 1
        if e < 0:
            e += 2 * y - 1
        else:
            x -= 1
            e += 2 * (y - x) - 1
    points += [(y, x) for x, y in points if x > y]
    points += [(-x, y) for x, y in points if x]
    points += [(x, -y) for x, y in points if y]
    points.sort()
    return points

def render(text, font, gfcolor=pygame.Color('dodgerblue'), ocolor=(255, 255, 255), opx=2):
    textsurface = font.render(text, True, gfcolor).convert_alpha()
    w = textsurface.get_width() + 2 * opx
    h = font.get_height()

    osurf = pygame.Surface((w, h + 2 * opx)).convert_alpha()
    osurf.fill((0, 0, 0, 0))

    surf = osurf.copy()

    osurf.blit(font.render(text, True, ocolor).convert_alpha(), (0, 0))

    for dx, dy in _circlepoints(opx):
        surf.blit(osurf, (dx + opx, dy + opx))

    surf.blit(textsurface, (opx, opx))
    return surf

def main():
    pygame.init()

    font = pygame.font.SysFont(None, 64)

    screen = pygame.display.set_mode((350, 100))
    clock = pygame.time.Clock()

    while True:
        events = pygame.event.get()
        for e in events:
            if e.type == pygame.QUIT:
                return
        screen.fill((30, 30, 30))

        screen.blit(render('Hello World', font), (20, 20))

        pygame.display.update()
        clock.tick(60)

if __name__ == '__main__':
    main()