> A while back on the list, there was a discussion about a text run
> having a shadow copy of the text to be used just for rendering (the
> discussion arose, AFAIR, from a discussion of how the various
> rendering engines use different character sets and encodings other
> than our 16 bit stuff). In a nutshell, it would have these kinds of
> characteristics:
>
> 1. Produced on demand at first render time if the rendered text was
> in some way different from the actual text (for example, remapped
> glyphs are such cases, whereas smart quote substitutions are not).
>
> 2. If the text in the run were altered in any way, the shadow copy
> would be discarded. Then, see step #1.
>
This would have an additional great advantage; by chaching the
text of the run, we could actually draw the whole text by a single
call to the OS graphical rutines; at the moment we draw every
single character individually (at least on Unix), which is also a
performance hindrance.
The thing that does worry me a bit, is that our memory
requirements could easily swell doing this; we would need some
kind of logic to ensure that only runs currently on the screen had
the chache.
Tomas
