On Thu, Apr 13, 2017 at 2:26 AM, Werner LEMBERG <[email protected]> wrote: > >> Rendered glyphs passed to OpenGL as a texture and then "properly" >> blended with a background color show dark pixels on the edges. >> [...] > > I'm no expert w.r.t. blending, but I think you get these artifacts if > you don't do the blending in linear color space. In other words, you > have to undo gamma, apply the blending, then apply gamma again. > > Look, for example, at this page > > http://ninedegreesbelow.com/photography/linear-gamma-blur-normal-blend.html >
I really appreciate the link. That helps me narrow it down to the blending mode. Unfortunately I'm not able to find any useful information to follow that up with. I realize that it is almost certainly not a FreeType2 issue at this point, but you seem to have a better idea of where to go next than I do. I tried referring to https://en.wikipedia.org/wiki/Blend_modes to determine what the most commonly suggested OpenGL blending mode, `GL_ONE_MINUS_SRC_ALPHA`, corresponds to, but was unable to figure it out. I'm also not really sure what to call the blending operation in what you gave me so that I can search for it. A page (http://web.archive.org/web/20081207015323/http://www.processingblogs.org/2007/03/31/mini-tutorial-additive-blending/) suggested using GL_ONE but I did not see any change in my results when using it. Better documentation references extensions which allow more customization in the blending parameters but all of the suggested options replicate what I am already experiencing (https://www.khronos.org/opengl/wiki/Blending#Colors). Some experimentation leads me to wonder if my desired result can even be obtained because I see the same behavior in commercial software. In the case of PowerShell it seems like the colors were selected to make the blending artifacts, if they are that, less noticeable, as the developers were unable to remove them. Cheers, R0b0t1. _______________________________________________ Freetype mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/freetype
