On 10/22/2015 12:55 PM, Nikolaus Waxweiler wrote:
Mac OS X is probably doing it that way (Dave? ;)).
I haven't checked lately, but a couple of years ago, Apple (MacOS and iOS) was doing something strange. There were indeed using linear blending for subpixel/LCD rendering. Here, there is an additional requirement. You need to blend in a linear color space in order to cancel out the color fringing. They used gamma 2.0. But Apple was using non-linear blending (gamma 1.0) for grayscale antialias. I don't know why, unless it was some kind of compatibility goal with older versions of the OS. This caused really strange effects when the rendering mode changed, as it did for an iPad rotated from landscape to portrait. There were even bloggers suggesting that you needed to switch to a lighter weight font in portrait mode, without understanding why. They just noticed that the black text looked heavier when linear blending was turned off. Microsoft Windows has been doing linear blending for a long time (20 years?) for both grayscale and "ClearType". They used a default gamma of 1.4, but starting in Windows XP gave users the ability to configure gamma. I believe Google's Android has a default blending gamma of 1.4, but individual vendors are free to change this, and some do. -Dave _______________________________________________ Freetype-devel mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/freetype-devel
