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'''This implements a virtual screen. This is used to support ANSI terminal
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emulation. The screen representation and state is implemented in this class.
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Most of the methods are inspired by ANSI screen control codes. The
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:class:`~pexpect.ANSI.ANSI` class extends this class to add parsing of ANSI
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This license is approved by the OSI and FSF as GPL-compatible.
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http://opensource.org/licenses/isc-license.txt
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Copyright (c) 2012, Noah Spurrier <noah@noah.org>
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PERMISSION TO USE, COPY, MODIFY, AND/OR DISTRIBUTE THIS SOFTWARE FOR ANY
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PURPOSE WITH OR WITHOUT FEE IS HEREBY GRANTED, PROVIDED THAT THE ABOVE
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COPYRIGHT NOTICE AND THIS PERMISSION NOTICE APPEAR IN ALL COPIES.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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NUL = 0 # Fill character; ignored on input.
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ENQ = 5 # Transmit answerback message.
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BEL = 7 # Ring the bell.
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BS = 8 # Move cursor left.
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HT = 9 # Move cursor to next tab stop.
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CR = 13 # Move cursor to left margin or newline.
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SO = 14 # Invoke G1 character set.
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SI = 15 # Invoke G0 character set.
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XON = 17 # Resume transmission.
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XOFF = 19 # Halt transmission.
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CAN = 24 # Cancel escape sequence.
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SUB = 26 # Same as CAN.
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ESC = 27 # Introduce a control sequence.
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DEL = 127 # Fill character; ignored on input.
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SPACE = chr(32) # Space or blank character.
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def constrain (n, min, max):
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'''This returns a number, n constrained to the min and max bounds. '''
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'''This object maintains the state of a virtual text screen as a
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rectangluar array. This maintains a virtual cursor position and handles
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scrolling as characters are added. This supports most of the methods needed
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by an ANSI text screen. Row and column indexes are 1-based (not zero-based,
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def __init__ (self, r=24,c=80):
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'''This initializes a blank screen of the given dimensions.'''
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self.scroll_row_start = 1
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self.scroll_row_end = self.rows
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self.w = [ [SPACE] * self.cols for c in range(self.rows)]
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'''This returns a printable representation of the screen. The end of
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each screen line is terminated by a newline. '''
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return '\n'.join ([ ''.join(c) for c in self.w ])
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'''This returns a copy of the screen as a string. This is similar to
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__str__ except that lines are not terminated with line feeds. '''
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return ''.join ([ ''.join(c) for c in self.w ])
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'''This returns a copy of the screen as a string with an ASCII text box
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around the screen border. This is similar to __str__ except that it
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top_bot = '+' + '-'*self.cols + '+\n'
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return top_bot + '\n'.join(['|'+line+'|' for line in str(self).split('\n')]) + '\n' + top_bot
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def fill (self, ch=SPACE):
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self.fill_region (1,1,self.rows,self.cols, ch)
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def fill_region (self, rs,cs, re,ce, ch=SPACE):
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rs = constrain (rs, 1, self.rows)
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re = constrain (re, 1, self.rows)
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cs = constrain (cs, 1, self.cols)
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ce = constrain (ce, 1, self.cols)
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for r in range (rs, re+1):
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for c in range (cs, ce + 1):
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self.put_abs (r,c,ch)
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'''This moves the cursor to the beginning (col 1) of the current row.
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self.cursor_home (self.cur_r, 1)
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'''This moves the cursor down with scrolling.
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if old_r == self.cur_r:
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'''This advances the cursor with CRLF properties.
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The cursor will line wrap and the screen may scroll.
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'''This is an alias for crlf().
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def put_abs (self, r, c, ch):
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'''Screen array starts at 1 index.'''
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r = constrain (r, 1, self.rows)
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c = constrain (c, 1, self.cols)
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self.w[r-1][c-1] = ch
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'''This puts a characters at the current cursor position.
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self.put_abs (self.cur_r, self.cur_c, ch)
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def insert_abs (self, r, c, ch):
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'''This inserts a character at (r,c). Everything under
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and to the right is shifted right one character.
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The last character of the line is lost.
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r = constrain (r, 1, self.rows)
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c = constrain (c, 1, self.cols)
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for ci in range (self.cols, c, -1):
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self.put_abs (r,ci, self.get_abs(r,ci-1))
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self.put_abs (r,c,ch)
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def insert (self, ch):
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self.insert_abs (self.cur_r, self.cur_c, ch)
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def get_abs (self, r, c):
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r = constrain (r, 1, self.rows)
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c = constrain (c, 1, self.cols)
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return self.w[r-1][c-1]
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self.get_abs (self.cur_r, self.cur_c)
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def get_region (self, rs,cs, re,ce):
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'''This returns a list of lines representing the region.
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rs = constrain (rs, 1, self.rows)
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re = constrain (re, 1, self.rows)
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cs = constrain (cs, 1, self.cols)
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ce = constrain (ce, 1, self.cols)
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for r in range (rs, re+1):
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for c in range (cs, ce + 1):
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ch = self.get_abs (r,c)
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def cursor_constrain (self):
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'''This keeps the cursor within the screen area.
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self.cur_r = constrain (self.cur_r, 1, self.rows)
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self.cur_c = constrain (self.cur_c, 1, self.cols)
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def cursor_home (self, r=1, c=1): # <ESC>[{ROW};{COLUMN}H
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self.cursor_constrain ()
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def cursor_back (self,count=1): # <ESC>[{COUNT}D (not confused with down)
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self.cur_c = self.cur_c - count
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self.cursor_constrain ()
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def cursor_down (self,count=1): # <ESC>[{COUNT}B (not confused with back)
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self.cur_r = self.cur_r + count
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self.cursor_constrain ()
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def cursor_forward (self,count=1): # <ESC>[{COUNT}C
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self.cur_c = self.cur_c + count
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self.cursor_constrain ()
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def cursor_up (self,count=1): # <ESC>[{COUNT}A
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self.cur_r = self.cur_r - count
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self.cursor_constrain ()
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def cursor_up_reverse (self): # <ESC> M (called RI -- Reverse Index)
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if old_r == self.cur_r:
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def cursor_force_position (self, r, c): # <ESC>[{ROW};{COLUMN}f
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'''Identical to Cursor Home.'''
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self.cursor_home (r, c)
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def cursor_save (self): # <ESC>[s
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'''Save current cursor position.'''
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self.cursor_save_attrs()
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def cursor_unsave (self): # <ESC>[u
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'''Restores cursor position after a Save Cursor.'''
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self.cursor_restore_attrs()
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def cursor_save_attrs (self): # <ESC>7
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'''Save current cursor position.'''
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self.cur_saved_r = self.cur_r
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self.cur_saved_c = self.cur_c
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def cursor_restore_attrs (self): # <ESC>8
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'''Restores cursor position after a Save Cursor.'''
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self.cursor_home (self.cur_saved_r, self.cur_saved_c)
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def scroll_constrain (self):
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'''This keeps the scroll region within the screen region.'''
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if self.scroll_row_start <= 0:
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self.scroll_row_start = 1
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if self.scroll_row_end > self.rows:
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self.scroll_row_end = self.rows
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def scroll_screen (self): # <ESC>[r
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'''Enable scrolling for entire display.'''
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self.scroll_row_start = 1
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self.scroll_row_end = self.rows
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def scroll_screen_rows (self, rs, re): # <ESC>[{start};{end}r
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'''Enable scrolling from row {start} to row {end}.'''
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self.scroll_row_start = rs
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self.scroll_row_end = re
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self.scroll_constrain()
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def scroll_down (self): # <ESC>D
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'''Scroll display down one line.'''
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# Screen is indexed from 1, but arrays are indexed from 0.
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s = self.scroll_row_start - 1
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e = self.scroll_row_end - 1
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self.w[s+1:e+1] = copy.deepcopy(self.w[s:e])
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def scroll_up (self): # <ESC>M
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'''Scroll display up one line.'''
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# Screen is indexed from 1, but arrays are indexed from 0.
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s = self.scroll_row_start - 1
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e = self.scroll_row_end - 1
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self.w[s:e] = copy.deepcopy(self.w[s+1:e+1])
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def erase_end_of_line (self): # <ESC>[0K -or- <ESC>[K
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'''Erases from the current cursor position to the end of the current
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self.fill_region (self.cur_r, self.cur_c, self.cur_r, self.cols)
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def erase_start_of_line (self): # <ESC>[1K
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'''Erases from the current cursor position to the start of the current
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self.fill_region (self.cur_r, 1, self.cur_r, self.cur_c)
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def erase_line (self): # <ESC>[2K
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'''Erases the entire current line.'''
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self.fill_region (self.cur_r, 1, self.cur_r, self.cols)
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def erase_down (self): # <ESC>[0J -or- <ESC>[J
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'''Erases the screen from the current line down to the bottom of the
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self.erase_end_of_line ()
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self.fill_region (self.cur_r + 1, 1, self.rows, self.cols)
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def erase_up (self): # <ESC>[1J
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'''Erases the screen from the current line up to the top of the
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self.erase_start_of_line ()
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self.fill_region (self.cur_r-1, 1, 1, self.cols)
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def erase_screen (self): # <ESC>[2J
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'''Erases the screen with the background color.'''
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def set_tab (self): # <ESC>H
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'''Sets a tab at the current position.'''
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def clear_tab (self): # <ESC>[g
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'''Clears tab at the current position.'''
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def clear_all_tabs (self): # <ESC>[3g
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'''Clears all tabs.'''
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# Insert line Esc [ Pn L
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# Delete line Esc [ Pn M
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# Delete character Esc [ Pn P
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# Scrolling region Esc [ Pn(top);Pn(bot) r
added
removed
pexpect/screen.py
