Add Font.set_linesize() (TTF 2.24.0 feature)

[itzpr3d4t0r]

We've long had the ability to get the line size with get_linesize(), but we've never had the ability to set the spacing between lines when rendering multiline text. Thanks to SDL_TTF 2.24.0 this PR adds the functionality.

[Starbuck5]

@itzpr3d4t0r I believe your tests are failing here because it runs the test suite over font as well as ftfont, and ftfont doesn't support this feature. Some other font tests specifically exclude themselves from running on ftfont.

[damusss]

As much as I don't like set_/get_ methods, get_linesize was already there, so not adding it would be rather weird (we can have just properties with pygame 3, I guess!). And Font.linesize can be added by another PR, too, so this LGTM, thanks for adding it :)

[Starbuck5]

What does SDL_ttf do if this isn't true? Also could be good to specify in the docs that this needs to be a positive number including zero.

[aatle]

When I tried allowing negative sizes, font.render() raised pygame.error for a large negative size (possibly when greater than height).
Documented constraint.

[Starbuck5]

This will be a great feature to get in! Left a few small notes / a question.

Wrote a sample program to test around with:

import pygame

pygame.init()
screen = pygame.display.set_mode((680, 420))
clock = pygame.time.Clock()
running = True

font = pygame.font.SysFont("Arial", 32)

def generate_text():
    return font.render(
        "Hello world\nThis is an example of\nmultiline text\nusing different spacings.",
        True,
        "black",
    )

text = generate_text()

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

        if event.type == pygame.KEYDOWN and event.key == pygame.K_UP:
            font.set_linesize(font.get_linesize() + 5)
            print(font.get_linesize())
            text = generate_text()

        if event.type == pygame.KEYDOWN and event.key == pygame.K_DOWN:
            font.set_linesize(font.get_linesize() - 5)
            print(font.get_linesize())
            text = generate_text()

    screen.fill("purple")

    for i in range(4):
        pygame.draw.rect(
            screen,
            "orangered" if i % 2 else "lightblue",
            [0, i * font.get_linesize(), 300, font.get_linesize()],
        )

    screen.blit(text)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()

[Starbuck5]

Last time I talked to itzpr he was busy IRL and okay with people taking over his PRs.

@aatle I was wondering if you were interested in taking this over, since you’re a member now you can push to itzprs branch. This could be a good first C PR for you, as it just needs some polishing up to get over the finish line.