Re: "Fix" sag scaling for hidpi

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> If someone explains what are the "logical" and "physical" pixel sizes,
> I could try figuring out what that means for the MS-Windows case.

Physical pixel size is what you'd think -- it's one actual pixel on the
screen.  (If the monitor is 1280 × 1024, you have (* 1280 1024) =>
1310720 physical pixels.)

"Logical" pixels was something that was introduced when people started
making high-resolution screens.  In a 2x HiDPI scenario, the OS will
report that the 1280 × 1024 is really a 640 x 512 screen, but if you
give it an image that's 640x512 to display, it'll scale it up, using
four physical pixels per logical pixel, and this will be blurry.

So you give it a 1280x1024 image if it's a logical 640x512 2x screen if
you don't want blurriness.  :-/

(Of course, with fonts you avoid the blurriness, because it'll just
render the fonts to whatever the physical pixels are.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no