Re: [TCLCORE] TIP #145 and font weights in Tk

[Benjamin R. <b.r...@tu...>]

Hi Daniel, Pat,


"Daniel A. Steffen" writes:
> You can ask for any numeric weight along a font's weight variation
> axis (if present), or with CoreText (10.5 and later) for normalized
> numeric weights between -1.0 and 1.0:
> 	http://developer.apple.com/documentation/Carbon/Reference/CTFontDescriptorRef/Reference/reference.html#/
> /apple_ref/doc/uid/TP40005107-CH4-SW1
> so the approach you used for Xft of choosing some arbitrary numeric
> font weight to correspond to a given symbolic name could work on OSX
> as well.

Right now in the Tk code, the font attributes are stored internally
using the old QuickDraw font attributes.  That is partly a holdover
from the old QuickDraw code and partly for the sake of the function
TkMacOSXInitControlFontStyle which is used in conjunction with the
Control Manager function SetControlFontStyle to initialize native
controls with QuickDraw-style font attributes.

QuickDraw compatibility functions from the Font Manager are used to
get from those attributes to the actual ATSUI font objects.

QuickDraw only has "bold" as an attribute, nothing else AFAIK.  But we
could go away from the QuickDraw compatibility code and use a more
ATSUI-like function to get font objects.

> You can also enumerate all font instances of a given font and
> compare their names to the asked-for weight name, that would allow
> finding e.g. a defined 'semibold' instance of a given font if
> present.

It seems to me that would introduce more "intelligence" (aka
"guesswork") into the system, on top of what the OS does already in
this regard.  I don't like that idea.


benny