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| """Simple textbox editing widget with Emacs-like keybindings.""" | |
| import curses | |
| import curses.ascii | |
| def rectangle(win, uly, ulx, lry, lrx): | |
| """Draw a rectangle with corners at the provided upper-left | |
| and lower-right coordinates. | |
| """ | |
| win.vline(uly+1, ulx, curses.ACS_VLINE, lry - uly - 1) | |
| win.hline(uly, ulx+1, curses.ACS_HLINE, lrx - ulx - 1) | |
| win.hline(lry, ulx+1, curses.ACS_HLINE, lrx - ulx - 1) | |
| win.vline(uly+1, lrx, curses.ACS_VLINE, lry - uly - 1) | |
| win.addch(uly, ulx, curses.ACS_ULCORNER) | |
| win.addch(uly, lrx, curses.ACS_URCORNER) | |
| win.addch(lry, lrx, curses.ACS_LRCORNER) | |
| win.addch(lry, ulx, curses.ACS_LLCORNER) | |
| class Textbox: | |
| """Editing widget using the interior of a window object. | |
| Supports the following Emacs-like key bindings: | |
| Ctrl-A Go to left edge of window. | |
| Ctrl-B Cursor left, wrapping to previous line if appropriate. | |
| Ctrl-D Delete character under cursor. | |
| Ctrl-E Go to right edge (stripspaces off) or end of line (stripspaces on). | |
| Ctrl-F Cursor right, wrapping to next line when appropriate. | |
| Ctrl-G Terminate, returning the window contents. | |
| Ctrl-H Delete character backward. | |
| Ctrl-J Terminate if the window is 1 line, otherwise insert newline. | |
| Ctrl-K If line is blank, delete it, otherwise clear to end of line. | |
| Ctrl-L Refresh screen. | |
| Ctrl-N Cursor down; move down one line. | |
| Ctrl-O Insert a blank line at cursor location. | |
| Ctrl-P Cursor up; move up one line. | |
| Move operations do nothing if the cursor is at an edge where the movement | |
| is not possible. The following synonyms are supported where possible: | |
| KEY_LEFT = Ctrl-B, KEY_RIGHT = Ctrl-F, KEY_UP = Ctrl-P, KEY_DOWN = Ctrl-N | |
| KEY_BACKSPACE = Ctrl-h | |
| """ | |
| def __init__(self, win, insert_mode=False): | |
| self.win = win | |
| self.insert_mode = insert_mode | |
| self._update_max_yx() | |
| self.stripspaces = 1 | |
| self.lastcmd = None | |
| win.keypad(1) | |
| def _update_max_yx(self): | |
| maxy, maxx = self.win.getmaxyx() | |
| self.maxy = maxy - 1 | |
| self.maxx = maxx - 1 | |
| def _end_of_line(self, y): | |
| """Go to the location of the first blank on the given line, | |
| returning the index of the last non-blank character.""" | |
| self._update_max_yx() | |
| last = self.maxx | |
| while True: | |
| if curses.ascii.ascii(self.win.inch(y, last)) != curses.ascii.SP: | |
| last = min(self.maxx, last+1) | |
| break | |
| elif last == 0: | |
| break | |
| last = last - 1 | |
| return last | |
| def _insert_printable_char(self, ch): | |
| self._update_max_yx() | |
| (y, x) = self.win.getyx() | |
| backyx = None | |
| while y < self.maxy or x < self.maxx: | |
| if self.insert_mode: | |
| oldch = self.win.inch() | |
| # The try-catch ignores the error we trigger from some curses | |
| # versions by trying to write into the lowest-rightmost spot | |
| # in the window. | |
| try: | |
| self.win.addch(ch) | |
| except curses.error: | |
| pass | |
| if not self.insert_mode or not curses.ascii.isprint(oldch): | |
| break | |
| ch = oldch | |
| (y, x) = self.win.getyx() | |
| # Remember where to put the cursor back since we are in insert_mode | |
| if backyx is None: | |
| backyx = y, x | |
| if backyx is not None: | |
| self.win.move(*backyx) | |
| def do_command(self, ch): | |
| "Process a single editing command." | |
| self._update_max_yx() | |
| (y, x) = self.win.getyx() | |
| self.lastcmd = ch | |
| if curses.ascii.isprint(ch): | |
| if y < self.maxy or x < self.maxx: | |
| self._insert_printable_char(ch) | |
| elif ch == curses.ascii.SOH: # ^a | |
| self.win.move(y, 0) | |
| elif ch in (curses.ascii.STX,curses.KEY_LEFT, curses.ascii.BS,curses.KEY_BACKSPACE): | |
| if x > 0: | |
| self.win.move(y, x-1) | |
| elif y == 0: | |
| pass | |
| elif self.stripspaces: | |
| self.win.move(y-1, self._end_of_line(y-1)) | |
| else: | |
| self.win.move(y-1, self.maxx) | |
| if ch in (curses.ascii.BS, curses.KEY_BACKSPACE): | |
| self.win.delch() | |
| elif ch == curses.ascii.EOT: # ^d | |
| self.win.delch() | |
| elif ch == curses.ascii.ENQ: # ^e | |
| if self.stripspaces: | |
| self.win.move(y, self._end_of_line(y)) | |
| else: | |
| self.win.move(y, self.maxx) | |
| elif ch in (curses.ascii.ACK, curses.KEY_RIGHT): # ^f | |
| if x < self.maxx: | |
| self.win.move(y, x+1) | |
| elif y == self.maxy: | |
| pass | |
| else: | |
| self.win.move(y+1, 0) | |
| elif ch == curses.ascii.BEL: # ^g | |
| return 0 | |
| elif ch == curses.ascii.NL: # ^j | |
| if self.maxy == 0: | |
| return 0 | |
| elif y < self.maxy: | |
| self.win.move(y+1, 0) | |
| elif ch == curses.ascii.VT: # ^k | |
| if x == 0 and self._end_of_line(y) == 0: | |
| self.win.deleteln() | |
| else: | |
| # first undo the effect of self._end_of_line | |
| self.win.move(y, x) | |
| self.win.clrtoeol() | |
| elif ch == curses.ascii.FF: # ^l | |
| self.win.refresh() | |
| elif ch in (curses.ascii.SO, curses.KEY_DOWN): # ^n | |
| if y < self.maxy: | |
| self.win.move(y+1, x) | |
| if x > self._end_of_line(y+1): | |
| self.win.move(y+1, self._end_of_line(y+1)) | |
| elif ch == curses.ascii.SI: # ^o | |
| self.win.insertln() | |
| elif ch in (curses.ascii.DLE, curses.KEY_UP): # ^p | |
| if y > 0: | |
| self.win.move(y-1, x) | |
| if x > self._end_of_line(y-1): | |
| self.win.move(y-1, self._end_of_line(y-1)) | |
| return 1 | |
| def gather(self): | |
| "Collect and return the contents of the window." | |
| result = "" | |
| self._update_max_yx() | |
| for y in range(self.maxy+1): | |
| self.win.move(y, 0) | |
| stop = self._end_of_line(y) | |
| if stop == 0 and self.stripspaces: | |
| continue | |
| for x in range(self.maxx+1): | |
| if self.stripspaces and x > stop: | |
| break | |
| result = result + chr(curses.ascii.ascii(self.win.inch(y, x))) | |
| if self.maxy > 0: | |
| result = result + "\n" | |
| return result | |
| def edit(self, validate=None): | |
| "Edit in the widget window and collect the results." | |
| while 1: | |
| ch = self.win.getch() | |
| if validate: | |
| ch = validate(ch) | |
| if not ch: | |
| continue | |
| if not self.do_command(ch): | |
| break | |
| self.win.refresh() | |
| return self.gather() | |
| if __name__ == '__main__': | |
| def test_editbox(stdscr): | |
| ncols, nlines = 9, 4 | |
| uly, ulx = 15, 20 | |
| stdscr.addstr(uly-2, ulx, "Use Ctrl-G to end editing.") | |
| win = curses.newwin(nlines, ncols, uly, ulx) | |
| rectangle(stdscr, uly-1, ulx-1, uly + nlines, ulx + ncols) | |
| stdscr.refresh() | |
| return Textbox(win).edit() | |
| str = curses.wrapper(test_editbox) | |
| print('Contents of text box:', repr(str)) | |