Re: unicode char ranges

[Hans Hagen <pragma@...>]

On 12/6/2012 8:22 PM, Jay Carlson wrote:

> I'll call it likely non-conformant and a bad example to draw lessons
> from. As a rule of thumb, display of NFC (generally, precomposed when 
> possible) and NFD (decomposed) should be indistinguishable, especially
> in the case of single combining marks; the fact that it is not makes 
> me suspect there are other bugs lurking around. The display itself is
> a bug if you consider crappy typography to be a bug (and I suspect
> you do, based on your complaint about the aesthetics of the
> decomposed case).

It has to do with resolution: in a precomposed glyph the glyph is one 
and snapping on the grid which can have a relation to screen pixels 
and/or anti-aliasing involves the whole shape (possibly driven by 
hinting). When composing, the shapes are independent and snapping is 
less related as there are 'moves' involved. So, at low resolutions 
things can easily look bad. If you have 1920 pixels / 100 glyphs you 
have less than 20 pixels per glyph. Add some margins and spacing and you 
have way less. In that respect it's already a miracle that things on the 
average look quite ok (partly thanks to subpixels juggling).

(When bitmap fonts were still the fashion one had to explicitly generate 
them for the output device and also make sure to compensate for a 
built-up of inaccuracy as well as snapping on the device grid. With 
outline fonts and cross platform portable floating point this is less an 
issue today.)

Hans


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