On 25 March 2011 04:54, Bill van Melle <[email protected]> wrote:

> I have an app in which I sometimes want to grey out images that are not the
> current images "of interest".  So I'm using a GrayscaleDecorator, which
> works fine for solid images.  But if the images have transparent parts, I
> want the decorator to leave them unaffected, so that the background shows
> through, rather than turning those pixels black.  Is there any way to do
> that?  Is this a bug in the decorator?


Pivot comes with a number of Decorator implementations.  If there isn't one
that does exactly you need, I wouldn't describe that as a bug.

http://pivot.apache.org/2.0/docs/api/org/apache/pivot/wtk/effects/Decorator.html

You are free to write your own implementations to meet your needs, so I
would recommend familiarizing yourself with the source of the various
provided Decorators, and then searching the net to find examples of how to
perform the one or more transformations/operations you might need.

For example, a quick search found this post demonstrating 3 different
grayscale conversion techniques and some comments discussing transparency.
http://blog.codebeach.com/2008/03/convert-color-image-to-gray-scale-image.html

Chris

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