He must be talking about the old greyscale antialiasing in the GDI. That one is better forgotten, it sucked for many reasons, & Cleartype wasn't that much better because of RGB sub-pixelling, but mainly because it was a much better antialiaser (& yet not amazing) than the poor old one.
Cleartype is calibrated for a gamma of 1.4 out of the box, & it's user-adjustable (& stored in the registry as "1400"). (sry I wasn't replying to the list) On Fri, Nov 1, 2013 at 6:31 AM, Werner LEMBERG <w...@gnu.org> wrote: > > Dave, > > > thanks a lot for your good demonstration images! > > > I believe column 3 is what we want to achieve. > > Yes, indeed! By the way, here is another page which goes into great > detail on gamma correction and TrueType font rendering: > > http://www.beatstamm.com/typography/RTRCh5.htm#Sec3 > > It might be interesting to see your tests applied to common TrueType > fonts also. Beat Stamm writes about GDI ClearType: > > In Windows, text rendered in full-pixel anti-aliasing is displayed > with a gamma correction done in software and using a gamma value of > about 2.3 – to determine this γ value, I displayed a gray ramp in > Word, inspected the RGB value of middle gray as rendered (189), > solved L = V(1/γ) (the formula for γ correction, as opposed to γ > response) for γ, and substituted the normalized inspected gray value > (189/255) for L while setting V to 0.5 (half the normalized voltage > should yield middle gray). Thus γ = log(V)/log(L) = > log(0.5)/log(189/255) ≅ 2.314. This gamma correction appears to be > in addition to what my premium graphics chip wants to do. If I > “under-correct” gamma on my graphics chip, all my photos look too > dark in their midtones, but text rendered in full-pixel > anti-aliasing looks more natural. If I “correct” gamma for my > photos, text rendered in full-pixel anti-aliasing looks “washed > out.” Windows (GDI) does not have any provisions to adjust or > defeat the software gamma correction of full-pixel anti-aliasing > (“standard font smoothing”). > > So it seems that similar problems are affecting even major > platforms... > > > Werner > _______________________________________________ > Freetype-devel mailing list > Freetype-devel@nongnu.org > https://lists.nongnu.org/mailman/listinfo/freetype-devel >
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