[lucida] incompatible sizes of arrows (uparrow and downarrow)

[Mikael Sundqvist]

Hi,

I am using Lucida OT. The sizes of \uparrow (U+2191) and \downarrow
(U+2193), used as delimiters, are not the same. I don't know if that
is to be considered as a bug in the font, but I think it would be
natural if they had the same size. The (ConTeXt) example below
generates the output shown in different.png. Note that the \downarrow
is longer than the \uparrow.

\setupbodyfont[lucida]
\starttext
\startTEXpage[offset=1dk]
\im{\left\uparrow P^{\uparrow} \right\uparrow} \par
\im{\left\downarrow P^{\uparrow} \right\downarrow}\par
\im{\left\uparrow P^{\uparrow} \right\downarrow}\par
\stopTEXpage
\stoptext

Looking at the unpacked font data, we find the following for the two glyphs:

% U+2191:
[8593]={
["boundingbox"]=85,
["index"]=390,
["math"]={
["vparts"]={
{
["advance"]=570,
["end"]=190,
["extender"]=1,
["glyph"]=983121,
["start"]=190,
},
{
["advance"]=637,
["end"]=212,
["glyph"]=8593,
["start"]=212,
},
},
},
["unicode"]=8593,
["width"]=604,
},

% U+2193:
[8595]={
["boundingbox"]=85,
["index"]=392,
["math"]={
["vparts"]={
{
["advance"]=630,
["end"]=210,
["glyph"]=8595,
["start"]=210,
},
{
["advance"]=570,
["end"]=190,
["extender"]=1,
["glyph"]=983121,
["start"]=190,
},
},
},
["unicode"]=8595,
["width"]=604,
},

It looks like the \downarrow (U+2193) is reporting a too small size
(rather than U+2191 reporting too large), which sometimes imply a
larger arrow. If I do change the data for U+2193 to the same as for
U+2191, i.e. change the second entry into (note the change in the
advance, end and start entries)

[8595]={
["boundingbox"]=85,
["index"]=392,
["math"]={
["vparts"]={
{
["advance"]=637,
["end"]=212,
["glyph"]=8595,
["start"]=212,
},
{
["advance"]=570,
["end"]=190,
["extender"]=1,
["glyph"]=983121,
["start"]=190,
},
},
},
["unicode"]=8595,
["width"]=604,
},

and rerun the same example file I get the output in same.png. Now it
looks fine (to me).

/Mikael
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