[ft-devel] [02/08] gamma correction issues with FreeType

[Werner LEMBERG]

>From Octoploid, who replied to Dave Arnold:

  > > No. I'm using a standard gamma of 2.2.  (But the font that I
  > > mostly use (Lexicon from Bram de Does) is quite dark by design.
  > > Darkening it too much makes it appear bold even in when using
  > > the "Light" weight.)
  >
  > The design weight of the font is factored into the computation of
  > darkening amount (assuming that the font correctly defines StdVW).
  > So I'm still curious about the description of the rendered text as
  > too dark.  I do not have access to a copy of Lexicon.  Have you
  > noticed the problem with other fonts, too?  Would you be willing
  > to send me a screen capture of the rendering, along with a
  > description of any custom darkening function that you may be
  > using?

  It may be my subjective impression only, but I've noticed this with
  other fonts, too.
  I've attached two screenshots of a Financial Times article.
  One with stock Freetype, the other with the following patch applied:

  diff --git a/src/cff/cffobjs.c b/src/cff/cffobjs.c
  index 29c369150846..5ac541503fdc 100644
  --- a/src/cff/cffobjs.c
  +++ b/src/cff/cffobjs.c
  @@ -1064,11 +1064,11 @@
       driver->no_stem_darkening = FALSE;

       driver->darken_params[0] =  500;
  -    driver->darken_params[1] =  400;
  +    driver->darken_params[1] =  300;
       driver->darken_params[2] = 1000;
  -    driver->darken_params[3] =  275;
  +    driver->darken_params[3] =  132;
       driver->darken_params[4] = 1667;
  -    driver->darken_params[5] =  275;
  +    driver->darken_params[5] =  175;
       driver->darken_params[6] = 2333;
       driver->darken_params[7] =    0;