--- /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
+
git.ucc.asn.au / progcomp10.git / blobdiff
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