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November 24th, 2003, 03:03 PM

jpjp

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pil and alpha

hi, ive got a string in "L" i convert to RGB, how do i add an alpha channel with an alpha based on the L value

November 25th, 2003, 01:17 AM

Igor Pechersky

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Trivial:

PHP Code:


		
			
 im1=im.convert("RGBA")

im1.putalpha(msk)

What's the problem?

November 25th, 2003, 08:28 AM

jpjp

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thanks, how do i display it now? im still getting the same alpha over the whole image. should i be using glBlendFunc(GL_SRC_ALPHA,GL_DST_ALPHA)

November 25th, 2003, 08:30 AM

jpjp

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also, should the alpha mask be from 0-255 ot 0.0-1.0?

November 25th, 2003, 09:29 AM

Igor Pechersky

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Quote:

how do i display it now? im still getting the same alpha over the whole image

I haven't got your point. Are you asking about PIL or about OpenGL?

Quote:

should the alpha mask be from 0-255 ot 0.0-1.0?

Any of them - either mode "L" or "1", in PIL jargon. Alpha mask is full-blown PIL image, just single-banded one

November 25th, 2003, 09:45 AM

jpjp

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sorry about the confusion, im having troubles varying the alpha in OpenGL. I can change the overall Alpha value using glColor4f but I see no varying alpha on the texture.

im assuming the alpha channel is int's 0-255 since the RGB channels are. the putalpha method comes up with no errors but i cant get getpixel(xy) to work. ive tried
im.getpixel([x,y])
im.getpixel(x,y)

temp=x*y
im.getpixel(temp)

November 25th, 2003, 04:07 PM

Igor Pechersky

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you've almost caught it

Code:

im.getpixel((x, y))

will return 4-tuple (if your image is really RGBA) of integers in 1..255 , like

Code:

(106, 106, 106, 196)

November 25th, 2003, 11:27 PM

jpjp

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thanks man

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