freetype-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[ft-devel] hinting and subpixel positioning


From: Alexei Podtelezhnikov
Subject: [ft-devel] hinting and subpixel positioning
Date: Fri, 19 May 2017 09:52:18 -0400

>> Define `consistent'.  For example, I could live with, say, four
>> different versions of glyph `a', dependent on the (fractional) start
>> position.
>
> Four hinted versions? May I ask how? Take letter 'l'. There is just one way 
> to cover a vertical run of pixels. You can have as many light versions as you 
> want. But strong version is unique.

Werner,,

I admittedly misunderstood grayscale normal hinting. Let's recoup and
see if you agree

In MONOCHROME mode subpixel positioning is impossible because stems
are nailed to grid.  Any shift in the start position will either be
ignored or result in jump to the next grid position. The hinted glyph
image is unique and only integer advances make sense.

In LIGHT mode, stems are unrestricted and subpixel positioning works.

In NORMAL mode, there is a bit more freedom in stem placement which
still must cover entire pixel whenever possible. Specifically if stem
widths are close one pixel, this freedom vanishes completely and
NORMAL becomes MONOCHROME. If stem widths is 1.5 pixel, NORMAL becomes
LIGHT. The fractional advance may or may not work depending on size.

Alexei



reply via email to

[Prev in Thread] Current Thread [Next in Thread]