I noticed that a non-trivial amount of dwm's work on my machine was from
drw_text, which seemed weird, because I have the bar disabled and we
only use drw_text as part of bar drawing.
Looking more closely, I realised that while we use m->showbar when
updating the monitor bar margins, but don't skip actually drawing the
bar if it is hidden. This patch skips drawing it entirely if that is the
case.
On my machine, this takes 10% of dwm's on-CPU time, primarily from
restack() and focus().
When the bar is toggled on again, the X server will generate an Expose
event, and we'll redraw the bar as normal as part of expose().
It generally doesn't make much sense to allow focusstack() to navigate
away from the selected fullscreen client, as you can't even see which
client you're selecting behind it.
I have had this up for a while on the wiki as a separate patch[0], but
it seems reasonable to avoid this behaviour in dwm mainline, since I'm
struggling to think of any reason to navigate away from a fullscreen
client other than a mistake.
0: https://dwm.suckless.org/patches/alwaysfullscreen/
This jarred me a bit while reading the code, since "sw" usually refers
to the global screen geometry, but in drawbar() only it refers to
text-related geometry. Renaming it makes it more obvious that these are
not related.
There are two places that mfact can be set:
- In the mfact global, which is defined at compile time and passed
into m->mfact during monitor setup. No bounds checks are performed,
but the comment alongside it says that valid values are [0.05..0.95]:
static const float mfact = 0.55; /* factor of master area size [0.05..0.95] */
- By setmfact, which adjusts m->mfact at runtime. It also does some
minimum and maximum bounds checks, allowing [0.1..0.9]. Values outside
of that range are ignored, and mfact is not adjusted.
These different thresholds mean that one cannot setmfact 0.95 or 0.05,
despite the comment above that lists the legal range for mfact.
Clarify this by enforcing the same bounds in setmfact at runtime as
those listed for mfact at compile time.
