I am hoping that someone can
shed light on whether off-curve points are considered when calculating a
OpenType glyph's bounding box. There is a check in Font Validator - E1112 -
that reads in part:
"The bounding box ... does not agree with the bounding
box dimensions defined by the control points at the extremes of the glyph
contours ... This problem may be caused by the font creation tool incorrectly using off-curve control points to calculate the bounding box ..."
The citation for this test is http://go.microsoft.com/fwlink?LinkID=10348 which is the glyph table specification. I can't glean
any information from that spec on whether to consider off-curve points.
Martin Hosken's FontUtils perl code (the Glyph.pm module) does use off-curve points (as far as I can tell). I can't off-hand
locate the code in the FontTools Python code.
Any guidance appreciated.
Comments
The "On-curve bounding box" approach suggested by FontValidator seems to be ?in error? or maybe overridden by general practice ...
Is there documentation on this? A search for "virtual extreme point" and related searches turns up nothing ...
by the way, I made up "virtual extreme point"... the wording makes sense to me, so don't take this term seriously.