On 9/10/15 14:32, Simon Cozens wrote:
On 09/10/2015 15:09, Khaled Hosny wrote:
On Thu, Oct 08, 2015 at 11:54:09AM -0400, Behdad Esfahbod wrote:
So, from my
point of view, you should NOT use this for line height calculation. You
should just use the typographical ascender/descender of the font and hence not
need glyph bounding boxes in Sile at all.
Yes please, an approach similar to what browsers do would be much
appreciated. TeX way of handling interline spacing has always been
cumbersome and confusing (not that I know exactly what SILE do now, but
the further from TeX way here the better).
OK. SILE currently does the same as TeX, and I agree that it's confusing.
I have just released SILE 0.9.3, so now I have a clean slate to play
with. I have merged the new shaping pipeline (sending whole paragraphs
to Harfbuzz) and moved over to HB OT functions, dropping the Freetype
dependency. This makes a *lot* of things happier. Bidi support is much
better, and it's now *much* faster too: my 28 page test document which
used to take 15 seconds in 0.9.3 now takes 5 seconds.
I'm happy to look at using the font ascender/descender metrics for line
heights - is there a good way to get those values out of Harfbuzz yet?
Grepping the repository doesn't turn up much. (There's also typographic
line gap information in the _hea table - should I be using that?)
You probably want to be using the "typographic" metrics from the OS/2
table, if present, with the hhea metrics as a fallback for fonts that
don't have OS/2. (They're rare, but can exist at least on OS X.)
JK
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