• Adobe After Effects Expressions

  How do I control the opacity of individual pixels?

  Posted by Dawood Al-kiyumi on August 11, 2012 at 2:21 am

  Hello everyone,

  I searched on the internet but found nothing.

  I want to control each pixel’s opacity depending on another pixel’s color on another layer.

  For example: if a pixel in a layer 1 has the same color (hsla) as the pixel in layer 2, the pixel opacity of layer 1 becomes 0. Otherwise the opacity is 100.

  I don’t know if this is actually possible.

  Thanks a lot in advance,
  Dawood

  Xavier Gomez replied 14 years ago 3 Members · 5 Replies
• 5 Replies

• 

  Dan Ebberts

  August 11, 2012 at 3:41 am

  I think you’d need to create a plugin to do that.

  Dan
• 

  Dawood Al-kiyumi

  August 11, 2012 at 11:47 am

  Hi Dan, Thanks.

  Do you know any good website or tutorial that you can suggest to me on how to create a plugin?

  I know it’s not that easy. But I’m kind of desperate to have this kind of control.
• 

  Dan Ebberts

  August 11, 2012 at 4:47 pm

  The best tutorial I know of is the SDK documentation itself. It sort of takes you through what you need to do to convert one of the example plugins to be your own. That part’s not too tough. However, there’s a pretty steep learning curve on figuring out how to make it do something different (like in your case–adding a layer control, checking out that layer, and getting pixels from it).

  It’s actually quite a bit of fun figuring it all out and getting a new plugin to work, it’s just that first one will take quite a while.

  Dan
• 

  Dawood Al-kiyumi

  August 11, 2012 at 6:23 pm

  Thank you very much, Dan.
  You are always helpful to us. ;D

  I’ll try my best and see what I can get.

  Chears,
  Dawood
• 

  Xavier Gomez

  August 11, 2012 at 9:20 pm

  I confirm, steep is the slope….

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