Now, `chres 640 480 2` can set the UI to HighDPI 640x480 at runtime. A
real GUI for changing the display factor will come later.
(`chres 640 480 2` followed by `chres 1280 960` is very fast since
we don't have to re-allocate the framebuffer since both modes use
the exact same number of physical pixels.)
Almost all logic stays in "logical" (unscaled coordinates), which
means the patch is small and things like DnD, window moving and
resizing, menu handling, menuapplets, etc all work without changes.
Screen knows about phyiscal coordinates and mouse handling internally is
in physical coordinates (so that two 1 pixel movements in succession can
translate to one 1 logical coordinate mouse movement -- only a single
event is sent in this case, on the 2nd moved pixel).
Compositor also knows about physical pixels for its backbuffers. This is
a temporary state -- in a follow-up, I'll try to let Bitmaps know about
their intrinsic scale, then Compositor won't have to know about pixels
any longer. Most of Compositor's logic stays in view units, just
blitting to and from back buffers and the cursor save buffer has to be
done in pixels. The back buffer Painter gets a scale applied which
transparently handles all drawing. (But since the backbuffer and cursor
save buffer are also HighDPI, they currently need to be drawn using a
hack temporary unscaled Painter object. This will also go away once
Bitmaps know about their intrinsic scale.)
With this, editing WindowServer.ini to say
Width=800
Height=600
ScaleFactor=2
and booting brings up a fully-functional HighDPI UI.
(Except for minimizing windows, which will crash the window server
until #4932 is merged. And I didn't test the window switcher since the
win-tab shortcut doesn't work on my system.) It's all pixel-scaled,
but it looks pretty decent :^)
