On 2009-04-23 13:24, Bert Freudenberg wrote:

On 23.04.2009, at 09:41, Angel Arias wrote:

i'd like to have different images in a project and change their alpha
property dynamically using scripts.

since i can't find the color category of an image in the viewer i
don't know how to access its alpha property.



Using Etoys tiles you can only hide and show an image completely, not  
adjust its transparency.

- Bert -

You can do image adjustments in a very slow way using a turtle to read each pixel and adjust the color and draw it another place :-)
I did a project that does that here:
http://wiki.laptop.org/images/8/8a/ColorReadingAndWriting-17.xo

To add alpha channel would not be hard, but this project is more prof of concept and it is slllllooooowwww

Karl