get the text of line using ncurses

[chuchi]

Hi!! I am developing an editor using ncurses and I am getting trouble with the lines of characters. Is there any way to get the text of a certain line?? or at least, to get the character of a certain position (x,y) written on the screen, so I can get all the characters of the line.

I know there is a lot of functions on man ncurses, but I have read and found nothing.

Thank you very much!!!

[jackj]

I'm certainly no expert, but I studied the following code which got me on my way. Maybe it will help you, too.



#!/usr/bin/env python
#
# $Id$
#
# (n)curses exerciser in Python, an interactive test for the curses
# module. Currently, only the panel demos are ported.

import curses
from curses import panel

def wGetchar(win = None):
if win is None: win = stdscr
return win.getch()

def Getchar():
wGetchar()

#
# Panels tester
#
def wait_a_while():
if nap_msec == 1:
Getchar()
else:
curses.napms(nap_msec)

def saywhat(text):
stdscr.move(curses.LINES - 1, 0)
stdscr.clrtoeol()
stdscr.addstr(text)

def mkpanel(color, rows, cols, tly, tlx):
win = curses.newwin(rows, cols, tly, tlx)
pan = panel.new_panel(win)
if curses.has_colors():
if color == curses.COLOR_BLUE:
fg = curses.COLOR_WHITE
else:
fg = curses.COLOR_BLACK
bg = color
curses.init_pair(color, fg, bg)
win.bkgdset(ord(' '), curses.color_pair(color))
else:
win.bkgdset(ord(' '), curses.A_BOLD)

return pan

def pflush():
panel.update_panels()
curses.doupdate()

def fill_panel(pan):
win = pan.window()
num = pan.userptr()[1]

win.move(1, 1)
win.addstr("-pan%c-" % num)
win.clrtoeol()
win.box()

maxy, maxx = win.getmaxyx()
for y in range(2, maxy - 1):
for x in range(1, maxx - 1):
win.move(y, x)
win.addch(num)

def demo_panels(win):
global stdscr, nap_msec, mod
stdscr = win
nap_msec = 1
mod = ["test", "TEST", "(**)", "*()*", "<-->", "LAST"]

stdscr.refresh()

for y in range(0, curses.LINES - 1):
for x in range(0, curses.COLS):
stdscr.addstr("%d" % ((y + x) % 10))
for y in range(0, 1):
p1 = mkpanel(curses.COLOR_RED,
curses.LINES // 2 - 2,
curses.COLS // 8 + 1,
0,
0)
p1.set_userptr("p1")

p2 = mkpanel(curses.COLOR_GREEN,
curses.LINES // 2 + 1,
curses.COLS // 7,
curses.LINES // 4,
curses.COLS // 10)
p2.set_userptr("p2")

p3 = mkpanel(curses.COLOR_YELLOW,
curses.LINES // 4,
curses.COLS // 10,
curses.LINES // 2,
curses.COLS // 9)
p3.set_userptr("p3")

p4 = mkpanel(curses.COLOR_BLUE,
curses.LINES // 2 - 2,
curses.COLS // 8,
curses.LINES // 2 - 2,
curses.COLS // 3)
p4.set_userptr("p4")

p5 = mkpanel(curses.COLOR_MAGENTA,
curses.LINES // 2 - 2,
curses.COLS // 8,
curses.LINES // 2,
curses.COLS // 2 - 2)
p5.set_userptr("p5")

fill_panel(p1)
fill_panel(p2)
fill_panel(p3)
fill_panel(p4)
fill_panel(p5)
p4.hide()
p5.hide()
pflush()
saywhat("press any key to continue")
wait_a_while()

saywhat("h3 s1 s2 s4 s5;press any key to continue")
p1.move(0, 0)
p3.hide()
p1.show()
p2.show()
p4.show()
p5.show()
pflush()
wait_a_while()

saywhat("s1; press any key to continue")
p1.show()
pflush()
wait_a_while()

saywhat("s2; press any key to continue")
p2.show()
pflush()
wait_a_while()

saywhat("m2; press any key to continue")
p2.move(curses.LINES // 3 + 1, curses.COLS // 8)
pflush()
wait_a_while()

saywhat("s3; press any key to continue")
p3.show()
pflush()
wait_a_while()

saywhat("m3; press any key to continue")
p3.move(curses.LINES // 4 + 1, curses.COLS // 15)
pflush()
wait_a_while()

saywhat("b3; press any key to continue")
p3.bottom()
pflush()
wait_a_while()

saywhat("s4; press any key to continue")
p4.show()
pflush()
wait_a_while()

saywhat("s5; press any key to continue")
p5.show()
pflush()
wait_a_while()

saywhat("t3; press any key to continue")
p3.top()
pflush()
wait_a_while()

saywhat("t1; press any key to continue")
p1.show()
pflush()
wait_a_while()

saywhat("t2; press any key to continue")
p2.show()
pflush()
wait_a_while()

saywhat("t3; press any key to continue")
p3.show()
pflush()
wait_a_while()

saywhat("t4; press any key to continue")
p4.show()
pflush()
wait_a_while()

for itmp in range(0, 6):
w4 = p4.window()
w5 = p5.window()

saywhat("m4; press any key to continue")
w4.move(curses.LINES // 8, 1)
w4.addstr(mod[itmp])
p4.move(curses.LINES // 6, itmp * curses.COLS // 8)
w5.move(curses.LINES // 6, 1)
w5.addstr(mod[itmp])
pflush()
wait_a_while()

saywhat("m5; press any key to continue")
w4.move(curses.LINES // 6, 1)
w4.addstr(mod[itmp])
p5.move(curses.LINES // 3 - 1, itmp * 10 + 6)
w5.move(curses.LINES // 8, 1)
w5.addstr(mod[itmp])
pflush()
wait_a_while()

saywhat("m4; press any key to continue")
p4.move(curses.LINES // 6, (itmp + 1) * curses.COLS // 8)
pflush()
wait_a_while()

saywhat("t5; press any key to continue")
p5.top()
pflush()
wait_a_while()

saywhat("t2; press any key to continue")
p2.top()
pflush()
wait_a_while()

saywhat("t1; press any key to continue")
p1.top()
pflush()
wait_a_while()

saywhat("d2; press any key to continue")
del p2
pflush()
wait_a_while()

saywhat("h3; press any key to continue")
p3.hide()
pflush()
wait_a_while()

saywhat("d1; press any key to continue")
del p1
pflush()
wait_a_while()

saywhat("d4; press any key to continue")
del p4
pflush()
wait_a_while()

saywhat("d5; press any key to continue")
del p5
pflush()
wait_a_while()
if nap_msec == 1:
break
nap_msec = 100

#
# one fine day there'll be the menu at this place
#
class gojo:
def start(self):
curses.wrapper(demo_panels)

if __name__ == '__main__':
g = gojo()
g.start()

[nvteighen]

I don't remember *any* function in ncurses designed to read from the screen.

Anyway, that's an awful design decision. Real manipulation of text should be done in a buffer data structure and the screen should be just a visual representation of the data held in that buffer. The reason is very simple: under what appears to be your approach, I wouldn't be able to type in more text than what the screen is able to show.

In what language are you writing this?

[chuchi]

Hi!! thank you very much!! I am writing in C using Linux of course

[itcotbtoemik]

Hi!! I am developing an editor using ncurses and I am getting trouble with the lines of characters. Is there any way to get the text of a certain line?? or at least, to get the character of a certain position (x,y) written on the screen, so I can get all the characters of the line.

I know there is a lot of functions on man ncurses, but I have read and found nothing.

Thank you very much!!!

man winch
man winchstr
man win_wch
man win_wchstr
man ncurses