Bug 7944

Up to and including pixelsize=14 the /zero's dot is a nice 1 pixel.  And usually
grey rather than black.

It looks good and is just visible enough to let one discern an /O from a /zero.

At pixelsize=17 the stems bump to 2px, below that they are 1px.

At pixelsize=16 the 2x2 block of the dot in /zero is mostly OK, since it is at
least centred in the counter.

But at 15 the 2x2 block is off-centre and distracts.

I tried changing the size of the dot's curve, but the grid-fitting is gives the
same results, so the change would have to be made in the instructions.

Looking at them, I suspect perhaps one of the cvt values controls this.  Maybe
cvt value 33, 151 or 165.  But the values shown in cvs in the debug window are
not the same as those in the edit_cvt window.  I presume the fpgm or prep must
change them....

In any case, I think either the dot's diameter should be no larger than the stem
widths at that pixelsize, or it should be tweaked just enough to keep it from
changing from one pixel to four pixels at pixelsize=16 rather than at pixelsize=15.

Oblique, Bold and Bold Oblique have similar issues, though each at different
sizes.  At one size the dot in Bold is so big it hits the stems and makes the
glyph look like a /theta....

(Appologies if this is less coherant than it should be; been up too long....)