Re: [ft] Suggestion to improve auto hinter

[Collyer, Oliver, SI]

Sent from my iPigeon

On 19 Feb 2011, at 06:44, "Werner LEMBERG" <address@hidden> wrote:

> 
>> - custom code in my application to draw the same glyph twice (on
>>  ontop of the other) as a means to thicken things up in the case of
>>  light text colours on dark backgrounds.
> 
> I'm not an expert for such rendering, but wouldn't it be sufficient to
> adapt the gamma values and doing proper blending, as demonstrated in
> the tutorial's example2.cpp?
> 

Im not an expert either, but I did experiment with gamma but couldn't produce 
the same effect. I'll have another go though, maybe I missed something.

>> So my suggestion is could FreeType's auto hinter do something like
>> this itself - e.g. if when working out all that clever latin blue
>> zone stuff, could it realise that actually it's making the font
>> smaller and a better result could be obtained by increasing the
>> requested pixel height and hinting at that height instead?  Or make
>> the hinter round up to the next line rather than round down, on the
>> basis that rounding up is likely to result in more readable text?
> 
> This is probably dependent on the font.  For example, I've just run
> ftdiff on pala.ttf, and the autohint's vertical size of glyphs is
> basically always the same as with the unhinted glyphs.  Do you have
> this `problem' all the time, regardless of the selected font?
> 

Yes it's dependent on the font or size or something - that's the point. Some 
fonts don't change height, some do.

I think verab at a requested height of 10 pixels ended up at 9 pixels after 
light hinting.

>> As you can see, number 4 is both sharp and of the requested height.
> 
> What about always adding, say, 0.25 pt to the requested font size?
> You might try the ftdiff demo program, where you can specify a
> non-integer font size with command line option -s.
> 

I'll experiment and see.

Thanks for the reply.
>