+++ /dev/null
-"""This implements a virtual screen. This is used to support ANSI terminal
-emulation. The screen representation and state is implemented in this class.
-Most of the methods are inspired by ANSI screen control codes. The ANSI class
-extends this class to add parsing of ANSI escape codes.
-
-$Id: screen.py 486 2007-07-13 01:04:16Z noah $
-"""
-
-import copy
-
-NUL = 0 # Fill character; ignored on input.
-ENQ = 5 # Transmit answerback message.
-BEL = 7 # Ring the bell.
-BS = 8 # Move cursor left.
-HT = 9 # Move cursor to next tab stop.
-LF = 10 # Line feed.
-VT = 11 # Same as LF.
-FF = 12 # Same as LF.
-CR = 13 # Move cursor to left margin or newline.
-SO = 14 # Invoke G1 character set.
-SI = 15 # Invoke G0 character set.
-XON = 17 # Resume transmission.
-XOFF = 19 # Halt transmission.
-CAN = 24 # Cancel escape sequence.
-SUB = 26 # Same as CAN.
-ESC = 27 # Introduce a control sequence.
-DEL = 127 # Fill character; ignored on input.
-SPACE = chr(32) # Space or blank character.
-
-def constrain (n, min, max):
-
- """This returns a number, n constrained to the min and max bounds. """
-
- if n < min:
- return min
- if n > max:
- return max
- return n
-
-class screen:
-
- """This object maintains the state of a virtual text screen as a
- rectangluar array. This maintains a virtual cursor position and handles
- scrolling as characters are added. This supports most of the methods needed
- by an ANSI text screen. Row and column indexes are 1-based (not zero-based,
- like arrays). """
-
- def __init__ (self, r=24,c=80):
-
- """This initializes a blank scree of the given dimentions."""
-
- self.rows = r
- self.cols = c
- self.cur_r = 1
- self.cur_c = 1
- self.cur_saved_r = 1
- self.cur_saved_c = 1
- self.scroll_row_start = 1
- self.scroll_row_end = self.rows
- self.w = [ [SPACE] * self.cols for c in range(self.rows)]
-
- def __str__ (self):
-
- """This returns a printable representation of the screen. The end of
- each screen line is terminated by a newline. """
-
- return '\n'.join ([ ''.join(c) for c in self.w ])
-
- def dump (self):
-
- """This returns a copy of the screen as a string. This is similar to
- __str__ except that lines are not terminated with line feeds. """
-
- return ''.join ([ ''.join(c) for c in self.w ])
-
- def pretty (self):
-
- """This returns a copy of the screen as a string with an ASCII text box
- around the screen border. This is similar to __str__ except that it
- adds a box. """
-
- top_bot = '+' + '-'*self.cols + '+\n'
- return top_bot + '\n'.join(['|'+line+'|' for line in str(self).split('\n')]) + '\n' + top_bot
-
- def fill (self, ch=SPACE):
-
- self.fill_region (1,1,self.rows,self.cols, ch)
-
- def fill_region (self, rs,cs, re,ce, ch=SPACE):
-
- rs = constrain (rs, 1, self.rows)
- re = constrain (re, 1, self.rows)
- cs = constrain (cs, 1, self.cols)
- ce = constrain (ce, 1, self.cols)
- if rs > re:
- rs, re = re, rs
- if cs > ce:
- cs, ce = ce, cs
- for r in range (rs, re+1):
- for c in range (cs, ce + 1):
- self.put_abs (r,c,ch)
-
- def cr (self):
-
- """This moves the cursor to the beginning (col 1) of the current row.
- """
-
- self.cursor_home (self.cur_r, 1)
-
- def lf (self):
-
- """This moves the cursor down with scrolling.
- """
-
- old_r = self.cur_r
- self.cursor_down()
- if old_r == self.cur_r:
- self.scroll_up ()
- self.erase_line()
-
- def crlf (self):
-
- """This advances the cursor with CRLF properties.
- The cursor will line wrap and the screen may scroll.
- """
-
- self.cr ()
- self.lf ()
-
- def newline (self):
-
- """This is an alias for crlf().
- """
-
- self.crlf()
-
- def put_abs (self, r, c, ch):
-
- """Screen array starts at 1 index."""
-
- r = constrain (r, 1, self.rows)
- c = constrain (c, 1, self.cols)
- ch = str(ch)[0]
- self.w[r-1][c-1] = ch
-
- def put (self, ch):
-
- """This puts a characters at the current cursor position.
- """
-
- self.put_abs (self.cur_r, self.cur_c, ch)
-
- def insert_abs (self, r, c, ch):
-
- """This inserts a character at (r,c). Everything under
- and to the right is shifted right one character.
- The last character of the line is lost.
- """
-
- r = constrain (r, 1, self.rows)
- c = constrain (c, 1, self.cols)
- for ci in range (self.cols, c, -1):
- self.put_abs (r,ci, self.get_abs(r,ci-1))
- self.put_abs (r,c,ch)
-
- def insert (self, ch):
-
- self.insert_abs (self.cur_r, self.cur_c, ch)
-
- def get_abs (self, r, c):
-
- r = constrain (r, 1, self.rows)
- c = constrain (c, 1, self.cols)
- return self.w[r-1][c-1]
-
- def get (self):
-
- self.get_abs (self.cur_r, self.cur_c)
-
- def get_region (self, rs,cs, re,ce):
-
- """This returns a list of lines representing the region.
- """
-
- rs = constrain (rs, 1, self.rows)
- re = constrain (re, 1, self.rows)
- cs = constrain (cs, 1, self.cols)
- ce = constrain (ce, 1, self.cols)
- if rs > re:
- rs, re = re, rs
- if cs > ce:
- cs, ce = ce, cs
- sc = []
- for r in range (rs, re+1):
- line = ''
- for c in range (cs, ce + 1):
- ch = self.get_abs (r,c)
- line = line + ch
- sc.append (line)
- return sc
-
- def cursor_constrain (self):
-
- """This keeps the cursor within the screen area.
- """
-
- self.cur_r = constrain (self.cur_r, 1, self.rows)
- self.cur_c = constrain (self.cur_c, 1, self.cols)
-
- def cursor_home (self, r=1, c=1): # <ESC>[{ROW};{COLUMN}H
-
- self.cur_r = r
- self.cur_c = c
- self.cursor_constrain ()
-
- def cursor_back (self,count=1): # <ESC>[{COUNT}D (not confused with down)
-
- self.cur_c = self.cur_c - count
- self.cursor_constrain ()
-
- def cursor_down (self,count=1): # <ESC>[{COUNT}B (not confused with back)
-
- self.cur_r = self.cur_r + count
- self.cursor_constrain ()
-
- def cursor_forward (self,count=1): # <ESC>[{COUNT}C
-
- self.cur_c = self.cur_c + count
- self.cursor_constrain ()
-
- def cursor_up (self,count=1): # <ESC>[{COUNT}A
-
- self.cur_r = self.cur_r - count
- self.cursor_constrain ()
-
- def cursor_up_reverse (self): # <ESC> M (called RI -- Reverse Index)
-
- old_r = self.cur_r
- self.cursor_up()
- if old_r == self.cur_r:
- self.scroll_up()
-
- def cursor_force_position (self, r, c): # <ESC>[{ROW};{COLUMN}f
-
- """Identical to Cursor Home."""
-
- self.cursor_home (r, c)
-
- def cursor_save (self): # <ESC>[s
-
- """Save current cursor position."""
-
- self.cursor_save_attrs()
-
- def cursor_unsave (self): # <ESC>[u
-
- """Restores cursor position after a Save Cursor."""
-
- self.cursor_restore_attrs()
-
- def cursor_save_attrs (self): # <ESC>7
-
- """Save current cursor position."""
-
- self.cur_saved_r = self.cur_r
- self.cur_saved_c = self.cur_c
-
- def cursor_restore_attrs (self): # <ESC>8
-
- """Restores cursor position after a Save Cursor."""
-
- self.cursor_home (self.cur_saved_r, self.cur_saved_c)
-
- def scroll_constrain (self):
-
- """This keeps the scroll region within the screen region."""
-
- if self.scroll_row_start <= 0:
- self.scroll_row_start = 1
- if self.scroll_row_end > self.rows:
- self.scroll_row_end = self.rows
-
- def scroll_screen (self): # <ESC>[r
-
- """Enable scrolling for entire display."""
-
- self.scroll_row_start = 1
- self.scroll_row_end = self.rows
-
- def scroll_screen_rows (self, rs, re): # <ESC>[{start};{end}r
-
- """Enable scrolling from row {start} to row {end}."""
-
- self.scroll_row_start = rs
- self.scroll_row_end = re
- self.scroll_constrain()
-
- def scroll_down (self): # <ESC>D
-
- """Scroll display down one line."""
-
- # Screen is indexed from 1, but arrays are indexed from 0.
- s = self.scroll_row_start - 1
- e = self.scroll_row_end - 1
- self.w[s+1:e+1] = copy.deepcopy(self.w[s:e])
-
- def scroll_up (self): # <ESC>M
-
- """Scroll display up one line."""
-
- # Screen is indexed from 1, but arrays are indexed from 0.
- s = self.scroll_row_start - 1
- e = self.scroll_row_end - 1
- self.w[s:e] = copy.deepcopy(self.w[s+1:e+1])
-
- def erase_end_of_line (self): # <ESC>[0K -or- <ESC>[K
-
- """Erases from the current cursor position to the end of the current
- line."""
-
- self.fill_region (self.cur_r, self.cur_c, self.cur_r, self.cols)
-
- def erase_start_of_line (self): # <ESC>[1K
-
- """Erases from the current cursor position to the start of the current
- line."""
-
- self.fill_region (self.cur_r, 1, self.cur_r, self.cur_c)
-
- def erase_line (self): # <ESC>[2K
-
- """Erases the entire current line."""
-
- self.fill_region (self.cur_r, 1, self.cur_r, self.cols)
-
- def erase_down (self): # <ESC>[0J -or- <ESC>[J
-
- """Erases the screen from the current line down to the bottom of the
- screen."""
-
- self.erase_end_of_line ()
- self.fill_region (self.cur_r + 1, 1, self.rows, self.cols)
-
- def erase_up (self): # <ESC>[1J
-
- """Erases the screen from the current line up to the top of the
- screen."""
-
- self.erase_start_of_line ()
- self.fill_region (self.cur_r-1, 1, 1, self.cols)
-
- def erase_screen (self): # <ESC>[2J
-
- """Erases the screen with the background color."""
-
- self.fill ()
-
- def set_tab (self): # <ESC>H
-
- """Sets a tab at the current position."""
-
- pass
-
- def clear_tab (self): # <ESC>[g
-
- """Clears tab at the current position."""
-
- pass
-
- def clear_all_tabs (self): # <ESC>[3g
-
- """Clears all tabs."""
-
- pass
-
-# Insert line Esc [ Pn L
-# Delete line Esc [ Pn M
-# Delete character Esc [ Pn P
-# Scrolling region Esc [ Pn(top);Pn(bot) r
-
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