changing opacity/transparency of an image

[David McFarlane]

Erin,

See also http://en.wikipedia.org/wiki/Alpha_compositing for 
theoretical background, from which you could derive specific 
programming steps for E-Prime or any other suitable programming platform.

-----
David McFarlane


At 8/7/2012 06:07 AM Tuesday, Larsen, Jeff wrote:
>I don't have access to my computer for a couple weeks, but we did 
>something similar a few years ago. Basically we made a canvas that 
>contained the picture but randomly replaced x% of the picture's 
>pixels with black dots with the setpixel function.
>
>Sent from my iPhone
>
>On Aug 6, 2012, at 6:13 PM, "Erin" 
><erin.siebert at gmail.com<mailto:erin.siebert at gmail.com>> wrote:
>
>I am trying to build an experiment where I incrementally "black out" 
>an image displayed on a black background.  I want to be able to set 
>the image opacity from 0% to 100% in 2% increments.  I will keep the 
>image opacity level constant within a session, but want to be able 
>to change it easily between sessions.  I know I could achieve this 
>in Photoshop by putting a black background behind my image, 
>adjusting the image's opacity, and re-saving the image.  However, I 
>want to be able to draw randomly from a very large bank of images 
>for each stage of the experiment, and it would be prohibitively 
>impractical to adjust all the images manually in Photoshop for each 
>opacity level.
>
>I found a post in this forum on how to fade between two different 
>colors (How to fade from slide1 to slide2 (inline?)), however I 
>haven't been able to find any information on 
>adjusting  opacity/transparency.  Any help would be very 
>appreciated.  Thank you!
>
>Erin

-- 
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To post to this group, send email to e-prime at googlegroups.com.
To unsubscribe from this group, send email to e-prime+unsubscribe at googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.