1 """This implements a virtual screen. This is used to support ANSI terminal 2 emulation. The screen representation and state is implemented in this class. 3 Most of the methods are inspired by ANSI screen control codes. The ANSI class 4 extends this class to add parsing of ANSI escape codes. 5 6 PEXPECT LICENSE 7 8 This license is approved by the OSI and FSF as GPL-compatible. 9 http://opensource.org/licenses/isc-license.txt 10 11 Copyright (c) 2012, Noah Spurrier <noah (at] noah.org> 12 PERMISSION TO USE, COPY, MODIFY, AND/OR DISTRIBUTE THIS SOFTWARE FOR ANY 13 PURPOSE WITH OR WITHOUT FEE IS HEREBY GRANTED, PROVIDED THAT THE ABOVE 14 COPYRIGHT NOTICE AND THIS PERMISSION NOTICE APPEAR IN ALL COPIES. 15 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 16 WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 17 MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 18 ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 19 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 20 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 21 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 22 23 """ 24 25 import copy 26 27 NUL = 0 # Fill character; ignored on input. 28 ENQ = 5 # Transmit answerback message. 29 BEL = 7 # Ring the bell. 30 BS = 8 # Move cursor left. 31 HT = 9 # Move cursor to next tab stop. 32 LF = 10 # Line feed. 33 VT = 11 # Same as LF. 34 FF = 12 # Same as LF. 35 CR = 13 # Move cursor to left margin or newline. 36 SO = 14 # Invoke G1 character set. 37 SI = 15 # Invoke G0 character set. 38 XON = 17 # Resume transmission. 39 XOFF = 19 # Halt transmission. 40 CAN = 24 # Cancel escape sequence. 41 SUB = 26 # Same as CAN. 42 ESC = 27 # Introduce a control sequence. 43 DEL = 127 # Fill character; ignored on input. 44 SPACE = chr(32) # Space or blank character. 45 46 def constrain (n, min, max): 47 48 """This returns a number, n constrained to the min and max bounds. """ 49 50 if n < min: 51 return min 52 if n > max: 53 return max 54 return n 55 56 class screen: 57 58 """This object maintains the state of a virtual text screen as a 59 rectangluar array. This maintains a virtual cursor position and handles 60 scrolling as characters are added. This supports most of the methods needed 61 by an ANSI text screen. Row and column indexes are 1-based (not zero-based, 62 like arrays). """ 63 64 def __init__ (self, r=24,c=80): 65 66 """This initializes a blank scree of the given dimentions.""" 67 68 self.rows = r 69 self.cols = c 70 self.cur_r = 1 71 self.cur_c = 1 72 self.cur_saved_r = 1 73 self.cur_saved_c = 1 74 self.scroll_row_start = 1 75 self.scroll_row_end = self.rows 76 self.w = [ [SPACE] * self.cols for c in range(self.rows)] 77 78 def __str__ (self): 79 80 """This returns a printable representation of the screen. The end of 81 each screen line is terminated by a newline. """ 82 83 return '\n'.join ([ ''.join(c) for c in self.w ]) 84 85 def dump (self): 86 87 """This returns a copy of the screen as a string. This is similar to 88 __str__ except that lines are not terminated with line feeds. """ 89 90 return ''.join ([ ''.join(c) for c in self.w ]) 91 92 def pretty (self): 93 94 """This returns a copy of the screen as a string with an ASCII text box 95 around the screen border. This is similar to __str__ except that it 96 adds a box. """ 97 98 top_bot = '+' + '-'*self.cols + '+\n' 99 return top_bot + '\n'.join(['|'+line+'|' for line in str(self).split('\n')]) + '\n' + top_bot 100 101 def fill (self, ch=SPACE): 102 103 self.fill_region (1,1,self.rows,self.cols, ch) 104 105 def fill_region (self, rs,cs, re,ce, ch=SPACE): 106 107 rs = constrain (rs, 1, self.rows) 108 re = constrain (re, 1, self.rows) 109 cs = constrain (cs, 1, self.cols) 110 ce = constrain (ce, 1, self.cols) 111 if rs > re: 112 rs, re = re, rs 113 if cs > ce: 114 cs, ce = ce, cs 115 for r in range (rs, re+1): 116 for c in range (cs, ce + 1): 117 self.put_abs (r,c,ch) 118 119 def cr (self): 120 121 """This moves the cursor to the beginning (col 1) of the current row. 122 """ 123 124 self.cursor_home (self.cur_r, 1) 125 126 def lf (self): 127 128 """This moves the cursor down with scrolling. 129 """ 130 131 old_r = self.cur_r 132 self.cursor_down() 133 if old_r == self.cur_r: 134 self.scroll_up () 135 self.erase_line() 136 137 def crlf (self): 138 139 """This advances the cursor with CRLF properties. 140 The cursor will line wrap and the screen may scroll. 141 """ 142 143 self.cr () 144 self.lf () 145 146 def newline (self): 147 148 """This is an alias for crlf(). 149 """ 150 151 self.crlf() 152 153 def put_abs (self, r, c, ch): 154 155 """Screen array starts at 1 index.""" 156 157 r = constrain (r, 1, self.rows) 158 c = constrain (c, 1, self.cols) 159 ch = str(ch)[0] 160 self.w[r-1][c-1] = ch 161 162 def put (self, ch): 163 164 """This puts a characters at the current cursor position. 165 """ 166 167 self.put_abs (self.cur_r, self.cur_c, ch) 168 169 def insert_abs (self, r, c, ch): 170 171 """This inserts a character at (r,c). Everything under 172 and to the right is shifted right one character. 173 The last character of the line is lost. 174 """ 175 176 r = constrain (r, 1, self.rows) 177 c = constrain (c, 1, self.cols) 178 for ci in range (self.cols, c, -1): 179 self.put_abs (r,ci, self.get_abs(r,ci-1)) 180 self.put_abs (r,c,ch) 181 182 def insert (self, ch): 183 184 self.insert_abs (self.cur_r, self.cur_c, ch) 185 186 def get_abs (self, r, c): 187 188 r = constrain (r, 1, self.rows) 189 c = constrain (c, 1, self.cols) 190 return self.w[r-1][c-1] 191 192 def get (self): 193 194 self.get_abs (self.cur_r, self.cur_c) 195 196 def get_region (self, rs,cs, re,ce): 197 198 """This returns a list of lines representing the region. 199 """ 200 201 rs = constrain (rs, 1, self.rows) 202 re = constrain (re, 1, self.rows) 203 cs = constrain (cs, 1, self.cols) 204 ce = constrain (ce, 1, self.cols) 205 if rs > re: 206 rs, re = re, rs 207 if cs > ce: 208 cs, ce = ce, cs 209 sc = [] 210 for r in range (rs, re+1): 211 line = '' 212 for c in range (cs, ce + 1): 213 ch = self.get_abs (r,c) 214 line = line + ch 215 sc.append (line) 216 return sc 217 218 def cursor_constrain (self): 219 220 """This keeps the cursor within the screen area. 221 """ 222 223 self.cur_r = constrain (self.cur_r, 1, self.rows) 224 self.cur_c = constrain (self.cur_c, 1, self.cols) 225 226 def cursor_home (self, r=1, c=1): # <ESC>[{ROW};{COLUMN}H 227 228 self.cur_r = r 229 self.cur_c = c 230 self.cursor_constrain () 231 232 def cursor_back (self,count=1): # <ESC>[{COUNT}D (not confused with down) 233 234 self.cur_c = self.cur_c - count 235 self.cursor_constrain () 236 237 def cursor_down (self,count=1): # <ESC>[{COUNT}B (not confused with back) 238 239 self.cur_r = self.cur_r + count 240 self.cursor_constrain () 241 242 def cursor_forward (self,count=1): # <ESC>[{COUNT}C 243 244 self.cur_c = self.cur_c + count 245 self.cursor_constrain () 246 247 def cursor_up (self,count=1): # <ESC>[{COUNT}A 248 249 self.cur_r = self.cur_r - count 250 self.cursor_constrain () 251 252 def cursor_up_reverse (self): # <ESC> M (called RI -- Reverse Index) 253 254 old_r = self.cur_r 255 self.cursor_up() 256 if old_r == self.cur_r: 257 self.scroll_up() 258 259 def cursor_force_position (self, r, c): # <ESC>[{ROW};{COLUMN}f 260 261 """Identical to Cursor Home.""" 262 263 self.cursor_home (r, c) 264 265 def cursor_save (self): # <ESC>[s 266 267 """Save current cursor position.""" 268 269 self.cursor_save_attrs() 270 271 def cursor_unsave (self): # <ESC>[u 272 273 """Restores cursor position after a Save Cursor.""" 274 275 self.cursor_restore_attrs() 276 277 def cursor_save_attrs (self): # <ESC>7 278 279 """Save current cursor position.""" 280 281 self.cur_saved_r = self.cur_r 282 self.cur_saved_c = self.cur_c 283 284 def cursor_restore_attrs (self): # <ESC>8 285 286 """Restores cursor position after a Save Cursor.""" 287 288 self.cursor_home (self.cur_saved_r, self.cur_saved_c) 289 290 def scroll_constrain (self): 291 292 """This keeps the scroll region within the screen region.""" 293 294 if self.scroll_row_start <= 0: 295 self.scroll_row_start = 1 296 if self.scroll_row_end > self.rows: 297 self.scroll_row_end = self.rows 298 299 def scroll_screen (self): # <ESC>[r 300 301 """Enable scrolling for entire display.""" 302 303 self.scroll_row_start = 1 304 self.scroll_row_end = self.rows 305 306 def scroll_screen_rows (self, rs, re): # <ESC>[{start};{end}r 307 308 """Enable scrolling from row {start} to row {end}.""" 309 310 self.scroll_row_start = rs 311 self.scroll_row_end = re 312 self.scroll_constrain() 313 314 def scroll_down (self): # <ESC>D 315 316 """Scroll display down one line.""" 317 318 # Screen is indexed from 1, but arrays are indexed from 0. 319 s = self.scroll_row_start - 1 320 e = self.scroll_row_end - 1 321 self.w[s+1:e+1] = copy.deepcopy(self.w[s:e]) 322 323 def scroll_up (self): # <ESC>M 324 325 """Scroll display up one line.""" 326 327 # Screen is indexed from 1, but arrays are indexed from 0. 328 s = self.scroll_row_start - 1 329 e = self.scroll_row_end - 1 330 self.w[s:e] = copy.deepcopy(self.w[s+1:e+1]) 331 332 def erase_end_of_line (self): # <ESC>[0K -or- <ESC>[K 333 334 """Erases from the current cursor position to the end of the current 335 line.""" 336 337 self.fill_region (self.cur_r, self.cur_c, self.cur_r, self.cols) 338 339 def erase_start_of_line (self): # <ESC>[1K 340 341 """Erases from the current cursor position to the start of the current 342 line.""" 343 344 self.fill_region (self.cur_r, 1, self.cur_r, self.cur_c) 345 346 def erase_line (self): # <ESC>[2K 347 348 """Erases the entire current line.""" 349 350 self.fill_region (self.cur_r, 1, self.cur_r, self.cols) 351 352 def erase_down (self): # <ESC>[0J -or- <ESC>[J 353 354 """Erases the screen from the current line down to the bottom of the 355 screen.""" 356 357 self.erase_end_of_line () 358 self.fill_region (self.cur_r + 1, 1, self.rows, self.cols) 359 360 def erase_up (self): # <ESC>[1J 361 362 """Erases the screen from the current line up to the top of the 363 screen.""" 364 365 self.erase_start_of_line () 366 self.fill_region (self.cur_r-1, 1, 1, self.cols) 367 368 def erase_screen (self): # <ESC>[2J 369 370 """Erases the screen with the background color.""" 371 372 self.fill () 373 374 def set_tab (self): # <ESC>H 375 376 """Sets a tab at the current position.""" 377 378 pass 379 380 def clear_tab (self): # <ESC>[g 381 382 """Clears tab at the current position.""" 383 384 pass 385 386 def clear_all_tabs (self): # <ESC>[3g 387 388 """Clears all tabs.""" 389 390 pass 391 392 # Insert line Esc [ Pn L 393 # Delete line Esc [ Pn M 394 # Delete character Esc [ Pn P 395 # Scrolling region Esc [ Pn(top);Pn(bot) r 396 397
