have a look, please, at the man page:
int DisplayHeight(Display *display, int screen_number);
int DisplayWidth(Display *display, int screen_number);
„What screen is that”? The one described by the parameters.
('display' is a pointer to a 'Display' structure returned by a
previous call to XOpenDisplay() )
So the man page for XOpenDisplay explains that you get the Display
structure by passing a description of which Xserver you are connecting to.
So using modern (2023) terminology:
Display *display - a structure describing Xserver instance (there
could be more than one running on the same computer)
int screen_number - an index of one of "root drawables"
I don't know exactly why they named things as they did. One possibility is
that the idea was that a display could consist of several physical
devices, like an airport display for arrivals and deparatures.
5. In fact the whole use of these macros is pretty much broken.
At least one person here notices and understands this. Yes, that's why
I suggested a fix.
One could discuss whether you like the name, but the macros give a
bounding box of what could be drawn (0, 0, screen_width, screen_height),
so this is actually useful.
I can go on... I understand on the surface what you say - but you can't
always
get what you want and to me it seems your understanding of X is very
superficial and thus you don't know the right way to do things
Then could you, please, suggest a „replacement functions” for these
two, that I could use to get the dimensions of physical screen —
whether is panning used, or not, is Xrandr used for that panning, or
anything else, is it Linux, or any of xBSD's etc.? In all these cases
t'll be still Xorg server, anyway.
Take a look at libxrandr, there are more details in an earlier e-mail.
best
Vladimir Dergachev
