Subpixel rendering has proven interesting. And that was the hinting parameter I was seeing in Unity Tweak Tool!
:tiphat: for explaining you two!
I think I just found
a good [EDIT3: not so good] replacement for my old gdipp, that enables the FreeType font rendering on Windows with plenty of possible tweaks, which is much easier to configure than gdipp -
MacType (2013.1231.0).
Unlike in gdipp, which configuration I needed to edit with a text editor and after every little tweak restart the service from the services manager to see the changes, this one has a GUI editor with sliders and instant preview window - MacTuner.exe, and the service doesn't need any restart after configuration tweaks/change, but just reload of the configuration file - with MacWiz.exe.
The best is to run MacTuner (as Administrator, unless you save the configuration in your profile) and MacWiz (which is set to be executed as Administrator by default) alongside, to make fast changes in the font rendering appearance.
You only need to set it to run as a service (it defaults to registry, which requires a restart in order to enable or disable the renderer), and change language from Chinese to English or Français on the first launch to understand what is written there.
EDIT: And it works fine without font rendering problems at least in GIMP, which didn't like the gdipp.
EDIT2: It will work in web browsers once you disable DirectWrite / Direct2D (in Chrome / Chromium with "chrome://settings#disable-direct-write" and in Pale Moon / Firefox with "gfx.direct2d.disabled"=true and "gfx.font_rendering.directwrite.enabled"=false in about:config).
EDIT3: MacType has been crashing (with StackHash) Pale Moon when viewing some webpages, so I'm going back to gdipp, and by the way the exception for Steam can be removed from it once you launch Steam with "
-no-dwrite" parameter.