[ft] Dark pixels at the edge of rendered glyphs.

[R0b0t1]

Hello,

Rendered glyphs passed to OpenGL as a texture and then "properly"
blended with a background color show dark pixels on the edges. The
bitmap is expanded into a fully white monochromatic image with an
alpha channel generated from the original glyph bitmap. The large
areas of black around the glyph are properly blended away but there
are dark (black or red to orange) pixels at the edge of some glyphs.

It seems like the dark pixels are an intentional choice to make the
glyphs more readable, but why are they there? Based on my rendering
process I am unable to explain why they still show up. I don't mean my
question to be specific to Microsoft Windows, but I see the same
artifacts in Windows' PowerShell and Visual Studio 2017 (both white
font on dark backgrounds).

It is my intent to have a glyph, if rendered white, fade into the
background color as seems the most logical result of what I am trying
to do.

Cheers,
     R0b0t1