Processing 1.0 - Processing Discourse - alpha channel lost after pixel copying

We closed this forum 18 June 2010. It has served us well since 2005 as the ALPHA forum did before it from 2002 to 2005. New discussions are ongoing at the new URL http://forum.processing.org. You'll need to sign up and get a new user account. We're sorry about that inconvenience, but we think it's better in the long run. The content on this forum will remain online.

Index › Suggestions & Bugs › Software Bugs › alpha channel lost after pixel copying

‹ Previous Topic | Next Topic ›

Pages: 1

alpha channel lost after pixel copying (Read 1138 times)

william

alpha channel lost after pixel copying
Sep 28^th, 2006, 10:33am

I loaded a png image with transparent background, then copy its pixels to a new PImage. The alpha channel was lost - transparent pixels rendered as white.

I tried to use the copy() method, which displayed a different result - transparent pixels rendered as gray.

See result here: http://www.metaphorical.net/temp/image_test.gif

Code here: http://www.metaphorical.net/temp/image_test.pde

PNG image used: http://www.metaphorical.net/temp/test.png

Daniel Shiffman

Re: alpha channel lost after pixel copying
Reply #1 - Sep 28^th, 2006, 4:02pm

You might consider using a mask to apply an alpha channel. This way you can load the original image, copy it multiple times, and then apply an alpha mask to all of the copies:

http://processing.org/reference/PImage_mask_.html

For your mask, all you'll need is that same circle colored white (fully opaque) with a black background (fully transparent.)

http://www.learningprocessing.com | http://www.shiffman.net | http://itp.nyu.edu

william YaBB Newbies Offline Posts: 12	Re: alpha channel lost after pixel copying Reply #2 - Oct 1^st, 2006, 11:46am Thanks shiffman. That's indeed the workaround I'm using right now... but it's a bit more difficult since the images are doing rotations and scaling.

william YaBB Newbies Offline Posts: 12	Re: alpha channel lost after pixel copying Reply #3 - Oct 1^st, 2006, 11:50am Downloaded 0117. The bug was fixed -- hurray!

Pages: 1

‹ Previous Topic | Next Topic ›