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#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <X11/Xlib.h>
#include <X11/keysym.h>
static int ignore_xerror(Display *display, XErrorEvent *ee) {
(void)display;
(void)ee;
return 0;
}
static void sigterm_handler(int dummy) {
(void)dummy;
}
static const KeySym toggle_overlay_key = XK_Z;
static void grab_keys(Display *display) {
unsigned int numlockmask = 0;
KeyCode numlock_keycode = XKeysymToKeycode(display, XK_Num_Lock);
XModifierKeymap *modmap = XGetModifierMapping(display);
for(int i = 0; i < 8; ++i) {
for(int j = 0; j < modmap->max_keypermod; ++j) {
if(modmap->modifiermap[i * modmap->max_keypermod + j] == numlock_keycode)
numlockmask = (1 << i);
}
}
XFreeModifiermap(modmap);
XErrorHandler prev_error_handler = XSetErrorHandler(ignore_xerror);
Window root_window = DefaultRootWindow(display);
unsigned int modifiers[] = { 0, LockMask, numlockmask, numlockmask|LockMask };
for(int i = 0; i < 4; ++i) {
XGrabKey(display, XKeysymToKeycode(display, toggle_overlay_key), Mod1Mask|modifiers[i], root_window, False, GrabModeAsync, GrabModeAsync);
}
XSync(display, False);
XSetErrorHandler(prev_error_handler);
}
static Window get_window_with_input_focus(Display *display) {
Window window = None;
int rev;
if(!XGetInputFocus(display, &window, &rev))
window = None;
return window;
}
int main() {
Display *display = XOpenDisplay(NULL);
if(!display) {
fprintf(stderr, "Error: XOpenDisplay failed\n");
return 1;
}
grab_keys(display);
const KeyCode overlay_keycode = XKeysymToKeycode(display, toggle_overlay_key);
XSetErrorHandler(ignore_xerror);
/* Killing gpu-screen-recorder with SIGTERM also gives us SIGTERM. We want to ignore that as that has no meaning here */
signal(SIGTERM, sigterm_handler);
XEvent xev;
for(;;) {
XNextEvent(display, &xev);
if(xev.type == KeyRelease && xev.xkey.keycode == overlay_keycode) {
Window window_with_input_focus = get_window_with_input_focus(display);
if(window_with_input_focus && window_with_input_focus != DefaultRootWindow(display)) {
char cmd[1024];
snprintf(cmd, sizeof(cmd), "/home/dec05eba/git/gpu-screen-recorder-overlay/sibs-build/linux_x86_64/debug/gpu-screen-recorder-overlay %ld", window_with_input_focus);
system(cmd);
}
}
}
return 0;
}
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