[ft-devel] AutoFit: Treat extrema of contours as edges for CJK glyph?

[Just Fill Bugs]

On 05/01/2011 03:27 PM, Just Fill Bugs wrote:
> On 04/29/2011 01:22 AM, address@hidden wrote:

>> About the other bluezones, it's difficult for me to recognize
>> remarkable improvement. Talking about the height/width proportion
>> of "想意", the non-autofitted results look like same size, but
>> both (old/new) autofitted results look like different size
>> (rather, "想" looks like as taller than "意").
>
> That's obviously because we failed to detect a top segment/edge for
> the 2 glyphs. Therefore we cannot 'lift' the top edges of the glyphs. 
> At the same time, the first detected horizontal edges are grid-fit
> to the lower grid. The result is a pressed down perception on the
> top of the glyphs.
>
> Cannot do much with blue zone before we can detect all the ending of a
> stem and also the extrema of a diagonal stem. It's not a problem of
> the blue zone fitting.
>

For CJK glyph, There are alway many diagonal stems that needed to
be fit with blue zones. However, since we cannot produce a horizontal
or vertical segment out of a diagonal stem, the stem cannot be blue
zoned, e.g. the top and the bottom of 户.

To solute the problem, I suggest to treat the extremas of every
contours in a glyph as edge lines. Then we can blue zone the edges
so that diagonal stems can also be aligned at top and bottom.

What do you think?

grid-hu4-nq8.png
Description: PNG image