Glyphs-Handbook-2013

UFO3 Font Info properties
are described on
unifiedfontobject.org/
versions/ufo3/fontinfo.html
this value. Also, when a small cap glyph is displayed in Edit
view and metrics are set to show, the small cap height will be
displayed instead of the x-height.
12.2.2 UFO 3 Parameters
These custom parameters, again presented in alphabetical
order, follow the naming convention for Font Info properties
as set forth in the UFO 3 specification published in March 2012.
Text between quotes is taken from the OpenType specification
on Microsoft’s site. As of version 1.3.18, Glyphs also makes
use of a simplified naming convention. Wherever possible,
you can leave out the prefix of the keyword, e.g., instead of
‘openTypeNameDescription’, you can simply use ‘description’,
or ‘blueScale’ instead of ‘postscriptBlueScale’. Both long and
short versions work side by side, though.
blueScale float BlueScale value. This corresponds to the Type 1/CFF
BlueScale field. Controls the font size until which overshoot
display is suppressed. Calculated as (pointsize at
you do not set the value yourself, blueScale defaults to 0.037,
em. This means that, in this case, overshoots will be visible if
at least 40 pixels are used to display an em. The maximum
blueScale value depends on the sizes of your alignment zones.
The maximum pointsize at 300 dpi is calculated as
alignment zone height) must be less than 240.
For example, your largest zone is 21 units deep, thus:
-
blueShift integer or float BlueShift value. This cor responds to the
Type 1/CFF BlueShift field. Default value is 7. Extends for very
small glyph features beyond the font size indicated by blueScale.
Overshoots inside an alignment zone are displayed if: (a)
they are equal to or larger than BlueShift and (b) if they are
smaller than BlueShift but larger than half a pixel. E.g. blueScale
is set to suppress overshoots until 32 PPM, blueShift is 6,
Glyphs Handbook, May 2013 89