Unicode font text shadow in fullscreen mode

Confirmed (Tested with French)

Could not reproduce with a language 'Pyccknn' and in 'Francais (France)'. All unicode font shadowing was nice. Including windowed and fullscreen, menus and f3-text. Notably, my F3-text was also unscaled, unlike in that screenshot.
(Edit: the screenshot shows something that looks like 1.5x scaled up size, and thus the half-a-pixels problems, and apparently that affects the shadows. I'd actually except those visual results when the fonts are scaled up with non-integer ratios.)
(Edit2: I fetched and installed the 13w10b just before testing this, if that matters any.)

Windowed mode looks fine, fullscreen not.
Remark: My monitor has a resolution of 1680 x 1050 pixels
Edit: Maybe this is question of aspect ratio

Added f3-screenshot 'f3-screenie.png' with the francais (france) as language on my system. (Sorry for the size, but it has to be fullscreen 😛) As can be seen, both the font and shadows look fine.

Edit: Ah, I had GUI scale "normal". When I selected "auto", menus were showing similar ugly stuff when scaled at certain levels. (Every second scale (the integer ratios) looks fine, every other looks bad).
At my 2560x1600 display, the fullscreen debug stuff looks still good, just even larger. (See 'f3-screenie-2.png')

So, basically, seems that is is font/font scaling issue, not shadow alignment issue. (That is, it is trying to increase the size of 1 pixel wide shapes into 1.5 pixel wide shapes; of course that won't work and looks awful without anti-aliasing).

The shadow could be generated slightly differently for perhaps a bit better result, but not much more can be done for it, without either anti-aliasing, or adjusting the fonts/glyphs, or not allowing fractional upscaling.

GUI scale: Small makes it even worse...

Yes, indeed, because at the small scale the font is in practice squeezed to half the original size. 1-pixel wide shapes in glyphs of 10 pixels tall become half-a-pixel wide shapes in 5-pixel tall glyphs and possibly half-a-pixel positions, too. No way to render those properly without anti-aliasing, and even with anti-aliasing it wouldn't be the nicest thing to look at, although readable.

I'm currently trying to figure out how to prevent it to use the x.5 scale factors when using unicode fonts. Or well, so far I don't even know how it scales texts, no matter what factor 😛 (Me OpenGL noob here. I did figure it out once before, more than a year ago, but have forgotten it already.)

Edit: alas, it looks a lot like the text scale factor is bound to the overall scale factor quiet tightly; the font rendered itself doesn't know about it, but the whole overlay / GUI is scaled as one piece. Thus, just poking the font rendering factor doesn't look quite as easy as I thought.

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.