[cairo] Semantics of transparent objects on opaque targets (image vs. PostScript)

Michael Sweet mike at easysw.com
Fri Jan 13 12:16:22 PST 2006

Carl Worth wrote:
> ...
> To me, this seems like the right thing to do, but it is a change
> compared to what the PostScript result has been up until now, so I
> wanted to confirm the decision here on the list before I updated the
> reference images for the PostScript output in the test suite.

I agree that this is the right thing to do - basically, if you don't
draw a background then you'll get an implementation/surface-defined
default background, which for PostScript output is white.


On a separate, nit-picky note, your PS output does not conform to
the Adobe Document Structuring Conventions:

     1. No Pages: comment in the header (you need at least a
        "%%Pages: (atend)" in the header)
     2. The header comments indicate ASCII (Clean7Bit) data, but
        you are embedding binary data.
     3. There is no %%EndPage comment defined by the DSC.
     4. Presumably you'll want a %%Pages comment after the
     5. Unless you are really using Level 3 language elements,
        the %%LanguageLevel comment should specify version 2.
        (this one is not really a DSC problem, but a general nit)

Once I have finished up CUPS 1.2 (probably sometime in March), I'll
be happy to work with you on this part of Cairo...

Michael Sweet, Easy Software Products           mike at easysw dot com
Internet Printing and Document Software          http://www.easysw.com

More information about the cairo mailing list