[Cairo] PDF 1.4 or 1.5

[Owen Taylor]

On Thu, 2003-08-14 at 15:49, Keith Packard wrote:
> Around 11 o'clock on Aug 14, "M. Evans" wrote:
> 
> > Now that 1.5 is out which of these models is Cairo targeting and why.
> 
> Can you explain what rendering model additions were made in 1.5?  1.4 
> added a *lot* of new rendering stuff that wasn't in 1.3 and makes it very 
> different from PostScript.

Perhaps the phrase on the cairographics.org main page is confusing:

  "Cairo provides a stateful user-level API with support for the 
   PDF 1.4 imaging model."

As far as I know, there is no intention at all to give Cairo an
imaging model that is nearly as complex as PDF 1.4.

Many of the effects you can get in PDF-1.4 are possible in the 
Cairo API. But many others (layer modes, complex gradients, etc)
aren't except in a Turing-complete type sense in which DrawPixel() 
also supports the PDF-1.4 imaging model.

"With capabilities similar to the PDF-1.4 imaging model" might 
more precisely express the intended meaning.

Regards,
						Owen