Re: [pygame] font alpha

[Mike Lawrence <Mike.Lawrence@xxxxxx>]

Got it. You need to blit the rendered text to a new surface then  
change the alpha value of that new surface before blitting it to screen.

import pygame
pygame.init()
screen = pygame.display.set_mode((640,480), pygame.SRCALPHA)
screen.fill((0,0,0))

myFont = pygame.font.Font(None, 30)

nonTransparent = myFont.render("This text should be fully opaque", 1,  
(255,255,255))
screen.blit(nonTransparent, (0,0))

myText = 'This text should be somewhat transparent'
semiTransparent = myFont.render(myText, 1, (255,255,255))
newSurf = pygame.Surface(myFont.size(myText))
newSurf.blit(semiTransparent,(0,0))
newSurf.set_alpha(100)
screen.blit(newSurf, (0,100))

pygame.display.flip()



On 5-Sep-07, at 9:47 PM, Mike Lawrence wrote:

> Good call Luke. Removing antialiasing did indeed result in a  
> surface with a usable set_alpha component.
>
> However, I'd really like to have antialiased text. Inserting  
> 'semiTransparent.convert_alpha()' between lines 9 and 10 didn't  
> seem to help either.
>
> On 5-Sep-07, at 9:18 PM, Luke Paireepinart wrote:
>
> > Mike Lawrence wrote:
> > > Hi all,
> > >
> > > Apologies for the seemingly newb help request but I can't seem to  
> > > figure out how to vary the alpha value of rendered font surfaces.  
> > > Here are my attempts thusfar:
> > >
> > > import pygame
> > > pygame.init()
> > > screen = pygame.display.set_mode((640,480), pygame.SRCALPHA)
> > > screen.fill((0,0,0))
> > >
> > > myFont = pygame.font.Font(None, 30)
> > > nonTransparent = myFont.render("This text should be fully  
> > > opaque", 1, (255,255,255))
> > > screen.blit(nonTransparent, (0,0))
> > > semiTransparent = myFont.render("This text should be somewhat  
> > > transparent", 1, (255,255,255))
> > > semiTransparent.set_alpha(100)
> > > screen.blit(semiTransparent, (0,100))
> > >
> > > pygame.display.flip()
> > > #When I flip, both messages are the same color, indicating that  
> > > the transparency on the second failed
> > I don't think that fonts are rendered with surface alpha to start.
> > does set_alpha apply surface alpha if they don't have it already?
> > Maybe try convert_alpha first?
> > It's possible that since you're aliasing the fonts they might be  
> > using per-pixel alpha which might conflict with surface alpha.
> > Just some suggestions, I've never tried this.
> > -Luke
> > > --
> > > Mike Lawrence
> > > Graduate Student, Department of Psychology, Dalhousie University
> > >
> > > Website: http://memetic.ca
> > >
> > > Public calendar: http://icalx.com/public/informavore/Public
> > >
> > > "The road to wisdom? Well, it's plain and simple to express:
> > > Err and err and err again, but less and less and less."
> > >     - Piet Hein
>
> --
> Mike Lawrence
> Graduate Student, Department of Psychology, Dalhousie University
>
> Website: http://memetic.ca
>
> Public calendar: http://icalx.com/public/informavore/Public
>
> "The road to wisdom? Well, it's plain and simple to express:
> Err and err and err again, but less and less and less."
> 	- Piet Hein

--
Mike Lawrence
Graduate Student, Department of Psychology, Dalhousie University

Website: http://memetic.ca

Public calendar: http://icalx.com/public/informavore/Public

"The road to wisdom? Well, it's plain and simple to express:
Err and err and err again, but less and less and less."
	- Piet Hein