Hi John, > > Support of modern font technologies and of course languages which > > aren't left-to-right. > > Agreed. But for everything else you've mentioned: it's just a matter > of writing another PDF postprocessor (or some other adapter for a > particular format). Postprocessors are where the real beauty of > Troff's staying power shines.
One could look at shoehorning evermore complexity through to the post-processor, but that denies integration with the rest of troff of the expressiveness of those features. Or at best, gives it through some clunky ‘treat it as a string’ mechanism. Think more of a language were expressions can have these as first-class things with powerful operators. > > but the modern graphics model of PDF has moved on a lot from theirs > > and isn't targeted. Images and SVG as first-class objects. > > Transformation matrices. Advanced colour handling. Text-flow > > layout. > > PDF's graphics model hasn't changed >From memory, PDF 1.3 added transitioning between colours, PDF 1.4 introduced transparency, and PDF 1.7 gave us 3D artwork. There must be many more incremental improvements. :-) > and SVG isn't a first class object in PDF documents. No, I know. I was meaning they would be in a new document-layout language. -- Cheers, Ralph.