[Arm-netbook] Alt Webpage & Logo Combo

[rhkramer at gmail.com]

Ahh, I intend that this be my last post on the subject, because it is pretty 
much OT for this list, but I re-read the bug report and saw a paragraph that 
was there before, but seems to have sunk in now:

`
Fontconfig has nothing to do with presenting the glyphs to the user, it simply 
selects the fonts. The bug you are seeing (and, yes, I agree that it is a bug 
even if white text on a black background is wrong) is due to limitations in 
various rendering libraries, like Xrender, cairo et al.
'

On Saturday, February 03, 2018 09:14:45 AM rhkramer at gmail.com wrote:
> On Saturday, February 03, 2018 09:02:10 AM rhkramer at gmail.com wrote:
> > I did find a bug report not too long ago for some application which
> > actually confirmed the bias I described, and described how that worked
> > (in general terms)--I'll make a cursory search or try to remember where
> > I found that, and, if I do, I'll post it here.
> 
> Ahh, that was easier than I expected--here are my notes after reading that
> bug report (some time ago)--I did not re-read it today to see if anything
> has changed.  The comments immediately after the [[<URL>][<Page Title>]]
> are my own, the things after the ` are quotations from the bug report.
> 
>    * [[https://bugs.freedesktop.org/show_bug.cgi?id=13431][Bug 13431:
> Summary: Gamma not taken into account, white on black hard to read]]--this
> confirms my observation of the problem, but my explanation (iirc) predates
> gamma correction (iir/uc)--my theory of the cause of the problem is that
> anti- aliasing sort of "assumed" that the normal view would be black on
> white, when it was applied to white on black, it should have somehow
> considered the other "color" (black or white) to be the basis--because it
> didn't, fewer pixels are colored white when viewing white on black as
> opposed to the number of pixels colored black when viewing black on white.
>  I don't know if the problem still exists--it probably does in at least
> some places, and, I still have more difficulty reading white (or a light
> color) on a black (or dark background). `
> When doing antialiasing, fontconfig-based renderers do not take gamma into
> account and assume a linear color space. This make black on white text
> difficult to read at small font sizez.
> 
> ...
> 
> The reason is that the stems of the glyphs are thinner than a whole pixel.
> Therefore, they get a fractionnal value. For example, the pixels on the
> lower part of the stem of the 'f' get the pixel value 151/255 in black on
> white, and 104/255 in white on black (and 104+151=255). With the usual 2.2
> gamma, this makes respectively 32% and 14%, which gives a contrast of 68%
> for black on white, and 14% for white on black.
> '