[cl-pdf-devel] transparency?

[Cyrus Harmon]

On May 24, 2007, at 2:39 PM, Marc Battyani wrote:

> "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.

What I want in this case is solid text on a transparent background.  
I'll keep digging.

> IIRC, the PNG also supports transparency for the images.

hmm... the png reading code says:

  (otherwise (error "Alpha channel not supported ~s" pathname))

so it would appear that pngs with alpha channels aren't supported,  
BICBW.

Thanks,

Cyrus