• per-pixel transparency
  • with fill([0,0,0,0])
  • without fill([0,0,0,0])
• full-surface transparency
  • with colorkey([0,0,0])
  • without colorkey([0,0,0])
• PyGame doc

per-pixel transparency

• image can have pixels with different transparences (alpha)
• it uses colors (R,G,B,A) instead of (R,G,B) ( (R,G,B) == (R,G,B,255) )
• it needs surface.convert_alpha()
• surface.fill([0,0,0,0]) gives transparent background (important is only alpha=0)
• it can't use set_alpha() to change transparency

with fill([0,0,0,0])

important is only alpha=0

without fill([0,0,0,0])

full-surface transparency

• it uses set_alpha() to change transparency
• it uses colors (R,G,B) - (R,G,B,A) makes no difference (it is treated as (R,G,B,255))
• surface.set_colorkey([0,0,0]) gives transparent background
  (it can be any color but [0,0,0] is default background color for new surface)

with colorkey([0,0,0])

without colorkey([0,0,0])

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PyGame doc

• pygame.Surface.convert_alpha,
• pygame.Surface.set_colorkey
• pygame.Surface.set_alpha