terminalcursesioctltermcapterminfo

Read screen character from terminal


As far I researched, terminfo/termcap and ioctl don't allow to query character at (x,y) position on terminal's screen. This is rather unexpected, because:

– the two mean that communication with terminal is bidirectional. Is there really no way to query a character at given position, like with *inch*, *in_wch* curses functions (which work only for curses windows)?


Solution

  • That's expected (not "unexpected"):

    Some (not all) terminals support an escape sequence which asks the terminal where the cursor is. The resize program uses that to obtain the screensize. But keep in mind that it is known to be terminal-dependent, as mentioned in the manual page:

    -s [rows columns]
    This option indicates that Sun console escape sequences will be used instead of the VT100-style xterm escape codes.

    Very few terminals support an escape sequence which will simply read characters from the screen. Not everyone likes the notion of a program that can read their screen — perhaps without their knowledge.