Re: [Devel] Rendering (by FreeType) and hinting of Latin small 'a'

[Vadim Plessky]

Hi David!

On Tuesday 10 September 2002 12:43 am, David Turner wrote:
|  Hello Vadim,
|
|  Vadim Plessky wrote:
|  > I'd like to discuss (again) rendering of Serif fonts, and, in particular
|  > (to narrow the scope) - Latin small 'a'.
|  > I have prepared a web page with examples demonstrating different
|  > rendering of this glyph
|  > http://freetype.newmail.ru/misc/hinting-a.html
|  > [...]
|  >
|  > Now about problem I see at a moment.
|  > 1) topology of 'a' is destroyed at all examples, except non-AA
|  > rendering. I refer here to central, near-horizontal curve, in the middle
|  > of 'a' enabling sub-pixel rgb decimation doesn't help here.
|
|  I have introduced some changes in the automatic and Postscript hinters
|  lately to deal with disappearing curved diagonals (like in "S" or "2").
|  There are chances that these might also enhance the hinting of
|  your "a"s. Could you test the rendering of the current CVS code
|  to see if something changed ??

Ok, I downloaded and tested current snapshot (from today).
Updated results of my testing are available here:
  http://freetype.newmail.ru/misc/experimental-a.html

In particular, updated parts are:
http://freetype.newmail.ru/misc/experimental-a.html#AA-hinted-last
http://freetype.newmail.ru/misc/experimental-a.html#AA-autohinted-last
http://freetype.newmail.ru/misc/experimental-a.html#Times-Clones-last
http://freetype.newmail.ru/misc/experimental-a.html#Times-Clones-last-nogrid
I have placed some comments on web page, plus will comment here.

Pro's and Con's vs. Aug.28 snapshot
-------------------------------------------
Pros:
*  vertical "shadow* stems disappeared (comparing to Aug.28 snapshot of 
freetype)
* in general, contrast is higher, which is Good

Cons:
* bottom part of the 'a' is still broken
* middle part of first 5 variants (a,b,c,d,e) is too light, though not 
completely broken like at the bottom
* auto hinter does much better job in not AA mode (!)

Neutral:
* glyphs are more narrow now
* there is no *droplet-like* ending on top of 'a'
I am not sure wether both these facts are Bad or Good.
It's kind of taste.
On the other hand, 'a' from my my Dutch New now looks like 'a' from Times New 
Roman.
And 'a' from Times New Roman looks like pregnant :-))
What does it mean?!..

// check this URL to see what I mean 
http://freetype.newmail.ru/misc/experimental-a.html#Times-Clones-last

Not FreeType's fault, but related and nees fix
---------------------------------------------------
As you can see from KWord screesnhots, oversampling (at 3x) with further 
re-scaling doesn't work very well with new version of FreeType.
While ftview screenshots demonstrate quite good rendering, same glyphs in 
KWord (which uses Qt3/XFree86) get "shadow stems", also some curves are 
visually broken.
I think this is caused by oversampling/rescaling effect. (pls correct me if I 
am wrong here)
This should be disabled in XFree86 with upcoming FT 2.1.3 release

As about comparision with FT 2.0.9 - well, progress is visible without 
magnifying glass. Keep it going! :-)

|
|  > 3) My testing of 5 different Times clones (variants), in addition to the
|  > version I develop,  demonstrates, that all variants of Times, with
|  > exception of Times New Roman, have similiar problem described above.
|  > See screenshots at th ebottom of th epage (Times New Roman is 2nd in
|  > series, each three rendered glyphs are 12pt, 11pt, 10pt Latin 'a')
|  >
[...]
|
|  Best Regards,
|
|  - David
|  _______________________________________________
|  Devel mailing list
|  address@hidden
|  http://www.freetype.org/mailman/listinfo/devel

-- 

Vadim Plessky
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