Re: [ft-devel] ttfautohint: How to install

[vernon adams]

On 19 Jun 2011, at 16:37, Werner LEMBERG wrote:

> 
>> I'm guessing the render differences are caused by my tests being run
>> on WinXP & Win7.
> 
> Interesting.  Is Win7 OK?  Does WinXP only fail?


On Chrome the Win7 & XP were near identical, as the browser uses GDI on both 
OS's.
I will do some tests using the system font viewer in Win7 & XP, to remove the 
chance of browser interference.


> 
>> Are your ftview shots from Windows?
> 
> No, from Linux.  But they should be absolutely identical since ftview
> renders the glyphs directly as graphics, bypassing the operating
> system's font handling completely.

But isn't it the system's (in our case, Windows) font handling that needs to be 
targetted? No point making an autohinter that can output great graphics but 
renders the fonts not-so-great in the browser :)

> 
>> Interestingly Chrome on Linux seems to override a font's hinting
>> settings now!?  Could this be part of the improved font rendering
>> that's rumoured for ChromeOS?  Standard hinted, autohinted & not
>> hinted versions of Ubuntu Font render same on Ubuntu Chrome!
> 
> Hmm.  Overriding the user's preferences is not optimal IMHO.

I'm guessing that this behaviour is in line with the Chrome OS direction where 
the browser is at the core. Of course a user can still set own prefs for screen 
rendering, Chrome OS is linux after all.

> 
>> On Ubuntu Firefox4 the combination of ttfautohint + version 1 gasp
>> gives superior rendering to manually hinted original Ubuntu Font imo
>> (see attached pngs)
> 
> :-)
> 
>> conclusion - Legacy Windows is the worst target :)
> 
> However, I don't understand where the differences come from.  Nothing
> in the hinting instructions added by ttfautohint is specific to
> ClearType.  It uses a large number of twilight points which is
> probably unusual a bit, but this doesn't explain how the asymmetry can
> come into existence.

Well i have no technical knowledge of the rendering stuff behind Cleartype or 
Freetype, but my eyes tell me that they render the same TT instructions 
differently

> 
> Perhaps I can activate my contacts to the font people at Microsoft,
> asking for help in case the rendering problems you observe are also
> present in Win7.

That would be good. Any light shed on how Cleartype utilises TT instructions 
would be great. It's not purely an OS version issue though - the big difference 
on Windows is between GDI and DirectWrite. XP is GDI only (i believe), wherease 
Win7 apps are able to render under either GDI or DirectWrite. Hence - FFox 4 
and IE9 on Windows utilise DirectWrite for superior font rendering. It's very 
likely that Win8 will use primarilly DirectWrite (if not purely). Same goes for 
the new MS Phone OS. With DirectWrite, hinting instructions become almost 
arbitrary. So... main target for font hinting is Windows GDI imo.

many thanks

-vern


> 
> 
>   Werner