a c program that showcases how to utilize the all event mouse reporting of terminals to create a hover effect

terminal_mouse_hover_effect_showcase.c

//Copyleft 2023 hym3242
//No rights reserved
//please forgive my bad code
//tested pass on FreeBSD 13.2
//inspired by vttest(1) and xterm manual concerning ctrl sequences (https://invisible-island.net/xterm/ctlseqs/ctlseqs.html)
//Usage: stty -echo -icanon; stdbuf -o0 ./mouse 2>debug_output.txt

#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>

void handler(int signal){
	(void)signal;
	write(1,"\033[?1003l",8); //disable mouse reporting before exit
	exit(1);
}

int main(){
	int status=0;
	int changed=0;
	int shouldbe=0;
	unsigned char buf[8];

	signal(SIGINT,handler);

	write(1,"\033[?1003h",8); //enable all-event mouse reporting
	write(1,"\033[10;10HHELLO",13);
	while(1){
		read(0,buf  ,1);//^[
		read(0,buf+1,1);//[
		read(0,buf+2,1);//M
		read(0,buf+3,1);//C
		read(0,buf+4,1);
		read(0,buf+5,1);

		changed=0;
		if((buf[4]>=42 && buf[4]<=46) && buf[5]==42){
			shouldbe=1;
		}else{shouldbe=0;}
		dprintf(2,"status=%d, shouldbe=%d, ",status,shouldbe);
		changed = status==shouldbe ? 0:1;
		dprintf(2,"changed=%d\n",changed);
		if(changed){
			if(shouldbe){
				printf("\033[10;10H\033[7mHELLO\033[0m");
				dprintf(2,"status %d -> 1\n",status);
				status=1;
			}else{
				printf("\033[10;10H\033[0mHELLO");
				dprintf(2,"status %d -> 0\n",status);
				status=0;
			}
		}
		printf("\033[%d;%dH",buf[5]-32,buf[4]-32);
	}
	return 0;
}