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- """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.
- PEXPECT LICENSE
- This license is approved by the OSI and FSF as GPL-compatible.
- http://opensource.org/licenses/isc-license.txt
- Copyright (c) 2012, Noah Spurrier <noah@noah.org>
- PERMISSION TO USE, COPY, MODIFY, AND/OR DISTRIBUTE THIS SOFTWARE FOR ANY
- PURPOSE WITH OR WITHOUT FEE IS HEREBY GRANTED, PROVIDED THAT THE ABOVE
- COPYRIGHT NOTICE AND THIS PERMISSION NOTICE APPEAR IN ALL COPIES.
- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- """
- 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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