[cl-pdf-devel] transparency?

[Marc Battyani]

"Cyrus Harmon" <ch-lisp at bobobeach.com> wrote:

> Is there a way that I can set the page background to be transparent  using 
> cl-pdf? I'd like to be able to draw (at least partially) opaque  items 
> onto a transparent background but can't figure out how to do so.


What do you mean by transparency? Alpha channels? The text drawing for 
instance has no background color so is already transparent except for the 
glyphs.

IIRC, the PNG also supports transparency for the images.

Otherwise the PDF format supports an exhaustive tranparency model (chapter 7 
in the PDF reference). So it's probably not that hard to do whatever you 
want to.

Marc