[Cairo] Color transforms

[Carl Worth]

On Jul 17, Owen Taylor wrote:
 > I would suggest that you should try to work the API so that the printing
 > API isn't glommed into the rendering API, but forms a separate layer;
 > that is, instead of cairo_showpage (context), have something more along
 > the lines of:
 > 
 >  print_job = cairo_print_job_new_file (filename);

I might take a contrary view that "printing" shouldn't be any harder
than any other kind of graphics creation. For example, I'd like to be
able to take a chunk of code that generates a PNG and just flip a
switch at one point in the code and generate a PDF instead.

 > Or whatever. If it's set up this way, then you don't have to worry about
 > having lots of methods that only apply for some output devices.

Hopefully there won't be lots of functions. I think most of the
device-specific stuff can be handled at that time of device-specific
surface creation.

show_page is certainly one one truly unique capability. Are there many
others that people can think of?

-Carl