[cairo] Cairo and ISO C++

[Bill Spitzak]

One thing that was proposed changing is whether changing the CTM effects 
already-set line width and fonts. It does now to match PostScript.

General opinion is that this is a mistake. Cairo is inconsistent as this 
is not true for paths and for the transform applied to source images, 
and most font backends are broken such that you cannot correctly draw 
text unless the CTM is the same as the one the font was in.

I suspect changing this would break no programs, as everybody always 
sets the line width after setting the CTM, simply to avoid this 
apparenlty broken behavior. Although ancient, this has some precedence 
in PostScript, as the NeWS interpreter did this for awhile and was not 
found to break any PostScript displays.

It may be nice to address this as part of the C++ standard.