I am using pygame.font.Font.render()
to render some text. I’d like the text to be translucent, ie have an alpha value other than 255, so I tried passing a color argument with an alpha value (eg (255, 0, 0, 150)
) as the color argument for pygame.font.Font.render()
but it didn’t have any effect. I also tried using pygame.Surface.convert_alpha()
on the resulting Surface object, but that didn’t do anything either. Any ideas?
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Answer
When using the pygame.font
module, the alpha channel of the text color is not taken into account when rendering a text, but see pygame.font.Font.render
:
Antialiased images are rendered to 24-bit RGB images. If the background is transparent a pixel alpha will be included.
Changed in pygame 2.0: per-surface alpha can be combined with per-pixel alpha.
Hence it is completely sufficient to set the transparency after rendering the text with set_alpha
. This even works for anti-aliased text:
font = pygame.font.SysFont(None, 150) text_surf = font.render('test text', True, (255, 0, 0)) text_surf.set_alpha(127) window.blit(text_surf, (x, y))
Minimal example: repl.it/@Rabbid76/PyGame-TransparentText
import pygame pygame.init() window = pygame.display.set_mode((500, 300)) clock = pygame.time.Clock() font = pygame.font.SysFont(None, 150) text_surf = font.render('test text', True, (255, 0, 0)) text_surf.set_alpha(127) background = pygame.Surface(window.get_size()) ts, w, h, c1, c2 = 50, *window.get_size(), (128, 128, 128), (64, 64, 64) tiles = [((x*ts, y*ts, ts, ts), c1 if (x+y) % 2 == 0 else c2) for x in range((w+ts-1)//ts) for y in range((h+ts-1)//ts)] for rect, color in tiles: pygame.draw.rect(background, color, rect) run = True while run: clock.tick(60) for event in pygame.event.get(): if event.type == pygame.QUIT: run = False window.blit(background, (0, 0)) window.blit(text_surf, text_surf.get_rect(center = window.get_rect().center)) pygame.display.flip() pygame.quit() exit()
By using the pygame.freetype
module, you can use a transparent color directly when creating a text surface:
ft_font = pygame.freetype.SysFont('Times New Roman', 150) text_surf2, text_rect2 = ft_font.render('test text', (255, 0, 0, 128)) window.blit(text_surf2, (x, y))
Or if you are rendering the text directly onto a surface:
ft_font = pygame.freetype.SysFont('Times New Roman', 150) ft_font.render_to(window, (x, y), 'test text', (255, 0, 0, 128))
Minimal example: repl.it/@Rabbid76/PyGame-TransparentFreeTypeText
import pygame import pygame.freetype pygame.init() window = pygame.display.set_mode((500, 300)) clock = pygame.time.Clock() ft_font = pygame.freetype.SysFont('Times New Roman', 150) text_surf2, text_rect2 = ft_font.render('test text', (255, 0, 0, 128)) background = pygame.Surface(window.get_size()) ts, w, h, c1, c2 = 50, *window.get_size(), (128, 128, 128), (64, 64, 64) tiles = [((x*ts, y*ts, ts, ts), c1 if (x+y) % 2 == 0 else c2) for x in range((w+ts-1)//ts) for y in range((h+ts-1)//ts)] for rect, color in tiles: pygame.draw.rect(background, color, rect) run = True while run: clock.tick(60) for event in pygame.event.get(): if event.type == pygame.QUIT: run = False window.blit(background, (0, 0)) text_rect = ft_font.get_rect('test text') text_rect.center = (window.get_width() // 2, window.get_height() // 2 - 70) ft_font.render_to(window, text_rect.topleft, 'test text', (255, 0, 0, 128)) text_rect2.center = (window.get_width() // 2, window.get_height() // 2 + 70) window.blit(text_surf2, text_rect2) pygame.display.flip() pygame.quit() exit()
See also Text and font