How to get combined resolution of all connected displays to Linux machine in C++?

Question

I found this question related, but not directly answering my question, which is:

How to get combined resolution of all connected displays to Linux machine in C++? (rectangle around all monitors, whichever placed)

I know quite little of C++, but I've written this code, unsure if it does the job correctly or not, as I do not have multiple monitors layout, I'm just coding something which will have to take into account all connected monitors.

Excerpt of my code follows:

#include <X11/Xlib.h>
#include <iostream>


        Display * my_display = XOpenDisplay(NULL);
        Screen * my_screen = XDefaultScreenOfDisplay(my_display);

        const int screen_width = my_screen->width;
        const int screen_height = my_screen->height;

        if (x_coord >= screen_width)
        {
            std::cerr
                << "X coord bigger than the screen width\n";

            return 1;
        }

        if (y_coord >= screen_height)
        {
            std::cerr
                << "Y coord bigger than the screen height\n";

            return 1;
        }

Thank you.

Say I have one HD monitor and one 4K monitor, how would you define their combined resolution? — n. m. could be an AI, Aug 21 '21 at 08:47
possible duplicate of: https://stackoverflow.com/questions/11367354/obtaining-list-of-all-xorg-displays — selbie, Aug 21 '21 at 08:56
@n.1.8e9-where's-my-sharem. rectangle around all monitors, whichever placed (I quote from my question) — Vlastimil Burián, Aug 21 '21 at 08:57
By the way, "display", "screen" and "monitor" are three distinct entities in the X11 world. The screen resolution you get is the combined resolution of all monitors as managed by xrandr. — n. m. could be an AI, Aug 21 '21 at 09:14

score 0 · Answer 1 · answered Aug 21 '21 at 20:41

One possible way seems to be (invoking shell commands not included in the answer, but shall be very simple):

xdpyinfo | awk '/dimensions:/ { print $2 }'

Comment: In a multi-monitor setup this will show the dimensions of the bounding box which contains all monitors.

Credit: https://unix.stackexchange.com/a/2682/126755

How to get combined resolution of all connected displays to Linux machine in C++?

1 Answers1