On some 1,5-2 years or so old thread in this mailing list :)
*looks at size of archive* :S
I don't think anybody else does it. Most other applications just either separate type face/style from type family or just provide B/I buttons. The bolder/lighter approach is more interesting, because then you can easily cycle between multiple faces. I'd love to see how this could be done in UI other than with two buttons (bolder/lighter) as well, actually :)
Well for me it will heavily depend on whether I actually Get the concept. Is the behaviour continuous or discrete (as in, can you set in just about any value or are you limited to a few specific ones?) Same for italics: you decide the slant of the text right? Can you specify just about any value?
I remember a person who proposed this handy pop-up slider where you can click and drag left and right pretty easily. If the above behaviour allows you to take just about any value, then I Could see a "bold" drop-down horizontal slider where as you slide around the font becomes bolder. If there are a finite number of values possible, then you could constrain the values of the slider.
Same with italics.
How does Inkscape actually handle all that though? By distorting the fonts to hell? (something I don't really have a problem with, as long as it doesn't cause the memory usage to go to hell because handling of long text always seems to eat up my memory like no tomorrow right now?)
Speaking of that person's handy slider thing, I don't suppose anybody is going to implement it anytime soon? (a pity, because it's real handy. One-click value adjustment. Somebody should really make that widget)