Re: [artworks] Ideas for new version

  • From: John Tytgat <John.Tytgat@xxxxxxxx>
  • To: artworks@xxxxxxxxxxxxx
  • Date: Tue, 09 Jan 2007 03:30:28 +0100

In message <0a7309a24e.martin@xxxxxxxxxxxxxxxxxxx> you wrote:

> One feature I am considering that would allow what you want is alpha 
> masking. This is a more general transparency option allowin 
> transparency graduations of any shape (and even more than that, e.g., 
> transparency levels as defined by a bitmap, e.g., a texture). The idea 
> of alpha masking is that you can apply any kind of object as an alpha 
> mask to another object and the colours of the first object control the 
> amount of transparency applied to the second. E.g., if the alpha mask 
> object was a circle with a radial fill from black to white, then this 
> would be the same as applying radial transparency to the second 
> object. By using a blend you can construct an alpha mask that fades 
> out along arbitrary edges. By using a bitmap as an alpha mask, each 
> pixel's darkness would specify the transparency to be used for the 
> second object.
> Alpha masks are available as graphics operators in various file 
> formats, e.g., SVG and PDF (and they are actually used by ArtWorks to 
> represent graduated transparency in exported SVG and PDF files) but I 
> do not think I have seen them offered as an explicit feature in a 
> program. Maybe because this is just a bit too complex to handle for 
> the user, so I am not certain whether it will make sense to add that.

Illustrator CS/2/3 can do this, it is called "soft mask" (like the PDF
technical term for it).

John Tytgat, in his comfy chair at home                                 BASS
John.Tytgat@xxxxxxxx                             ARM powered, RISC OS driven

Other related posts: