Specific Color Ink

[Dar Scott]

On Oct 8, 2006, at 9:20 PM, Bridger Maxwell wrote:

>  I have a need for an ink that makes an image visible ONLY if the  
> color
> beneath it is a specific color.  I was shooting for black, but I  
> can work
> with whatever color is possible.  I have a program where all empty  
> space is
> black.  This has advantages because it is very easy to move object  
> around
> without having to worry about how it fits into the background.  My  
> thought
> would be to have an image and an ink that shows up only where it is  
> black.
> Then I could give the black space a cool shiny black look (like  
> frontrow),
> or whatever else.


I'm a little confused about what you want.  You mention a "specific  
color" and then you want to have a "cool shiny black look" which I  
assume means that you put highlights on it.

This might do what you want:

This needs 2.7.

Choose any color or texture for your empty space color.  Make it  
transparent where you don't want color.  You can make an image that  
is transparent in those place and you can also build up a shape with  
multiple graphics grouped to together.  Call that the "empty space"  
object.

Group that with the image you want to move around with the image to  
the front.  Set the ink of the "empty space" and the group to  
blendSrcOver.  Set the ink of the image you want to move around to to  
blendSrcAtop.

The opaqueness of the objects in the group under the image will allow  
the image to show.  Outside of the image (or where it is transparent)  
the color or texture of the underlying "empty space" will show through.

If I missed what you want, I apologize.

You might not need any special ink.  An alternate approach would be  
to set the color of the card to black.  Make everything else not  
black.  Then put the moving image between everything else and the  
card.  That is, move it to the far back.

Dar


--
**************************************
Dar Scott
Dar Scott Consulting  and  Dar's Lab
8637 Horacio Place NE
Albuquerque, NM 87111

Lab, office, home:  +1 505 299 9497
Fax:                call above first
Skype:              ask

http://www.swcp.com/dsc
dsc at swcp.com

Computer programming
**************************************