**** patents! Hours, and days digging in the code for font rendering with cairo. I tried to find out why this "colored" subpixel antialising is not working although all option settings are set (in cairo) and in the source code of cairo the FT_SetLCDFilter call is really used! But the output does is just the same as with CAIRO_ANTIALIAS_GRAY,
... until I found THIS in the freetype config: /* Uncomment the line below if you want to activate sub-pixel rendering */ /* (a.k.a. LCD rendering, or ClearType) in this build of the library. */ /* */ /* Note that this feature is covered by several Microsoft patents */ /* and should not be activated in any default build of the library. */ /* */ /* This macro has no impact on the FreeType API, only on its */ /* _implementation_. For example, using FT_RENDER_MODE_LCD when calling */ /* FT_Render_Glyph still generates a bitmap that is 3 times wider than */ /* the original size in case this macro isn't defined; however, each */ /* triplet of subpixels has R=G=B. */ ARGH! It still does not look as good as with the pharos freetypeplugin, but AT LEAST it looks equally on windows and linux , yeh. attached are three screenshots comparing the different athens drawings with the freetypeplugin athens on linux vs ftplugin athens on windows vs ftplugin athens on windows with enabled FT_CONFIG_SUBPIXEL_RENDERING vs ftplugin 2015-01-31 10:18 GMT+01:00 stepharo <[email protected]>: > > In athens, there are "hints" you can set. > (CairoFontOptions/hintMetricsOff/hintMetricsOn/hintStyleFull ....) > I played a bit with different settings. Changing this settings change > the output, but I can not get it to look > like with the freetype plugin. I understand that this can not look > equally, because the FreeTypePlugin and caire work differently, > but the athens result looks bad compared with the other one. > > > >> - Pixel fitting. (The aliasing going on at the top of characters) Put >> Hinting: None in FreeType advanced features, and you will probably see >> something similar to the Athens rendering. >> > > Yes, we can change the freetypeplugin setting and cairofontoption > setting to make the output look equally - ugly :) > > > Nicolai > > Igor explained to me that FreeType offers a degenerated mode that when the > font does have the information for bold, kerning,.... > computes a "guessed and approximated" default. Cairo does not offer this > api else Athens would use it. > So what would be interesting is to test using font having all the > information to see if Cairo display well the fonts. > > Stef >
