xdisp.c 68.9 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* Display generation from window structure and buffer text.
2
   Copyright (C) 1985, 1986, 1987, 1988, 1992, 1993 Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
3 4 5 6 7

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
8
the Free Software Foundation; either version 2, or (at your option)
Jim Blandy's avatar
Jim Blandy committed
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */


#include "config.h"
#include <stdio.h>
/*#include <ctype.h>*/
#undef NULL
#include "lisp.h"
Jim Blandy's avatar
Jim Blandy committed
26
#include "frame.h"
Jim Blandy's avatar
Jim Blandy committed
27 28 29 30 31 32 33 34
#include "window.h"
#include "termchar.h"
#include "dispextern.h"
#include "buffer.h"
#include "indent.h"
#include "commands.h"
#include "macros.h"
#include "disptab.h"
35
#include "termhooks.h"
Jim Blandy's avatar
Jim Blandy committed
36 37 38 39 40 41 42 43 44 45 46 47

extern int interrupt_input;
extern int command_loop_level;

/* Nonzero means print newline before next minibuffer message.  */

int noninteractive_need_newline;

#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))

/* The buffer position of the first character appearing
Jim Blandy's avatar
Jim Blandy committed
48 49
 entirely or partially on the current frame line.
 Or zero, which disables the optimization for the current frame line. */
Jim Blandy's avatar
Jim Blandy committed
50 51 52 53 54 55
static int this_line_bufpos;

/* Number of characters past the end of this line,
   including the terminating newline */
static int this_line_endpos;

Jim Blandy's avatar
Jim Blandy committed
56
/* The vertical position of this frame line. */
Jim Blandy's avatar
Jim Blandy committed
57 58
static int this_line_vpos;

Jim Blandy's avatar
Jim Blandy committed
59
/* Hpos value for start of display on this frame line.
Jim Blandy's avatar
Jim Blandy committed
60 61 62 63 64 65 66 67
   Usually zero, but negative if first character really began
   on previous line */
static int this_line_start_hpos;

/* Buffer that this_line variables are describing. */
static struct buffer *this_line_buffer;

/* Set by try_window_id to the vpos of first of any lines
Jim Blandy's avatar
Jim Blandy committed
68
   scrolled on to the bottom of the frame.  These lines should
Jim Blandy's avatar
Jim Blandy committed
69 70 71 72
   not be included in any general scroll computation.  */
static int scroll_bottom_vpos;

/* Value of echo_area_glyphs when it was last acted on.
Jim Blandy's avatar
Jim Blandy committed
73
  If this is nonzero, there is a message on the frame
Jim Blandy's avatar
Jim Blandy committed
74 75 76 77
  in the minibuffer and it should be erased as soon
  as it is no longer requested to appear. */
char *previous_echo_glyphs;

Jim Blandy's avatar
Jim Blandy committed
78
/* Nonzero means truncate lines in all windows less wide than the frame */
Jim Blandy's avatar
Jim Blandy committed
79 80 81 82 83 84 85 86 87 88 89
int truncate_partial_width_windows;

Lisp_Object Vglobal_mode_string;

/* Marker for where to display an arrow on top of the buffer text.  */
Lisp_Object Voverlay_arrow_position;

/* String to display for the arrow.  */
Lisp_Object Voverlay_arrow_string;

/* Values of those variables at last redisplay.  */
90
static Lisp_Object last_arrow_position, last_arrow_string;
Jim Blandy's avatar
Jim Blandy committed
91 92 93 94

/* Nonzero if overlay arrow has been displayed once in this window.  */
static int overlay_arrow_seen;

Jim Blandy's avatar
Jim Blandy committed
95
/* If cursor motion alone moves point off frame,
Jim Blandy's avatar
Jim Blandy committed
96 97 98 99 100 101 102 103 104 105 106
   Try scrolling this many lines up or down if that will bring it back.  */
int scroll_step;

/* Nonzero if try_window_id has made blank lines at window bottom
 since the last redisplay that paused */
static int blank_end_of_window;

/* Number of windows showing the buffer of the selected window.
   keyboard.c refers to this.  */
int buffer_shared;

Jim Blandy's avatar
Jim Blandy committed
107
/* display_text_line sets these to the frame position (origin 0) of point,
Jim Blandy's avatar
Jim Blandy committed
108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170
   whether the window is selected or not.
   Set one to -1 first to determine whether point was found afterwards.  */

static int cursor_vpos;
static int cursor_hpos;

int debug_end_pos;

/* Nonzero means display mode line highlighted */
int mode_line_inverse_video;

static void echo_area_display ();
void mark_window_display_accurate ();
static void redisplay_windows ();
static void redisplay_window ();
static void try_window ();
static int try_window_id ();
static struct position *display_text_line ();
static void display_mode_line ();
static int display_mode_element ();
static char *fmodetrunc ();
static char *decode_mode_spec ();
static int display_string ();

/* Prompt to display in front of the minibuffer contents */
char *minibuf_prompt;

/* Width in columns of current minibuffer prompt.  */
int minibuf_prompt_width;

/* Message to display instead of minibuffer contents
   This is what the functions error and message make,
   and command echoing uses it as well.
   It overrides the minibuf_prompt as well as the buffer.  */
char *echo_area_glyphs;

/* true iff we should redraw the mode lines on the next redisplay */
int update_mode_lines;

/* Smallest number of characters before the gap
   at any time since last redisplay that finished.
   Valid for current buffer when try_window_id can be called.  */
int beg_unchanged;

/* Smallest number of characters after the gap
   at any time since last redisplay that finished.
   Valid for current buffer when try_window_id can be called.  */
int end_unchanged;

/* MODIFF as of last redisplay that finished;
   if it matches MODIFF, beg_unchanged and end_unchanged
   contain no useful information */
int unchanged_modified;

/* Nonzero if head_clip or tail_clip of current buffer has changed
   since last redisplay that finished */
int clip_changed;

/* Nonzero if window sizes or contents have changed
   since last redisplay that finished */
int windows_or_buffers_changed;


171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194
/* Specify m, a string, as a message in the minibuf.  If m is 0, clear out
   any existing message, and let the minibuffer text show through.  */
void
message1 (m)
     char *m;
{
  if (noninteractive)
    {
      if (noninteractive_need_newline)
	putc ('\n', stderr);
      noninteractive_need_newline = 0;
      fprintf (stderr, "%s\n", m);
      fflush (stderr);
    }
  /* A null message buffer means that the frame hasn't really been
     initialized yet.  Error messages get reported properly by
     cmd_error, so this must be just an informative message; toss it.  */
  else if (INTERACTIVE && FRAME_MESSAGE_BUF (selected_frame))
    {
#ifdef MULTI_FRAME
      Lisp_Object minibuf_frame;

      choose_minibuf_frame ();
      minibuf_frame = WINDOW_FRAME (XWINDOW (minibuf_window));
195
      FRAME_SAMPLE_VISIBILITY (XFRAME (minibuf_frame));
196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212
      if (FRAME_VISIBLE_P (selected_frame)
	  && ! FRAME_VISIBLE_P (XFRAME (minibuf_frame)))
	Fmake_frame_visible (WINDOW_FRAME (XWINDOW (minibuf_window)));
#endif

      if (m)
	echo_area_glyphs = m;
      else
	echo_area_glyphs = previous_echo_glyphs = 0;

      do_pending_window_change ();
      echo_area_display ();
      update_frame (XFRAME (XWINDOW (minibuf_window)->frame), 1, 1);
      do_pending_window_change ();
    }
}

Jim Blandy's avatar
Jim Blandy committed
213
/* Nonzero if FRAME_MESSAGE_BUF (selected_frame) is being used by print;
Jim Blandy's avatar
Jim Blandy committed
214 215 216
   zero if being used by message.  */
int message_buf_print;

217 218
/* Dump an informative message to the minibuf.  If m is 0, clear out
   any existing message, and let the minibuffer text show through.  */
Jim Blandy's avatar
Jim Blandy committed
219 220 221 222 223 224 225
/* VARARGS 1 */
void
message (m, a1, a2, a3)
     char *m;
{
  if (noninteractive)
    {
226 227 228 229 230 231 232 233 234
      if (m)
	{
	  if (noninteractive_need_newline)
	    putc ('\n', stderr);
	  noninteractive_need_newline = 0;
	  fprintf (stderr, m, a1, a2, a3);
	  fprintf (stderr, "\n");
	  fflush (stderr);
	}
Jim Blandy's avatar
Jim Blandy committed
235
    }
236
  else if (INTERACTIVE)
Jim Blandy's avatar
Jim Blandy committed
237
    {
238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
      /* The frame whose minibuffer we're going to display the message on.
	 It may be larger than the selected frame, so we need
	 to use its buffer, not the selected frame's buffer.  */
      FRAME_PTR echo_frame;
#ifdef MULTI_FRAME
      choose_minibuf_frame ();
      echo_frame = XFRAME (WINDOW_FRAME (XWINDOW (minibuf_window)));
#else
      echo_frame = selected_frame;
#endif

      /* A null message buffer means that the frame hasn't really been
	 initialized yet.  Error messages get reported properly by
	 cmd_error, so this must be just an informative message; toss it.  */
      if (FRAME_MESSAGE_BUF (echo_frame))
253
	{
254 255 256
	  if (m)
	    {
	      {
Jim Blandy's avatar
Jim Blandy committed
257
#ifdef NO_ARG_ARRAY
258 259 260 261
		int a[3];
		a[0] = a1;
		a[1] = a2;
		a[2] = a3;
Jim Blandy's avatar
Jim Blandy committed
262

263 264
		doprnt (FRAME_MESSAGE_BUF (echo_frame),
			FRAME_WIDTH (echo_frame), m, 0, 3, a);
Jim Blandy's avatar
Jim Blandy committed
265
#else
266 267 268 269 270 271 272 273 274 275 276 277 278
		doprnt (FRAME_MESSAGE_BUF (echo_frame),
			FRAME_WIDTH (echo_frame), m, 0, 3, &a1);
#endif /* NO_ARG_ARRAY */
	      }

	      message1 (FRAME_MESSAGE_BUF (echo_frame));
	    }
	  else
	    message1 (0);

	  /* Print should start at the beginning of the message
	     buffer next time.  */
	  message_buf_print = 0;
279
	}
Jim Blandy's avatar
Jim Blandy committed
280 281 282 283 284 285 286
    }
}

static void
echo_area_display ()
{
  register int vpos;
Jim Blandy's avatar
Jim Blandy committed
287
  FRAME_PTR f;
Jim Blandy's avatar
Jim Blandy committed
288

Jim Blandy's avatar
Jim Blandy committed
289 290
#ifdef MULTI_FRAME
  choose_minibuf_frame ();
291 292
#endif

Jim Blandy's avatar
Jim Blandy committed
293
  f = XFRAME (WINDOW_FRAME (XWINDOW (minibuf_window)));
Jim Blandy's avatar
Jim Blandy committed
294

Jim Blandy's avatar
Jim Blandy committed
295
  if (! FRAME_VISIBLE_P (f))
Jim Blandy's avatar
Jim Blandy committed
296 297
    return;

Jim Blandy's avatar
Jim Blandy committed
298
  if (frame_garbaged)
Jim Blandy's avatar
Jim Blandy committed
299 300
    {
      Fredraw_display ();
Jim Blandy's avatar
Jim Blandy committed
301
      frame_garbaged = 0;
Jim Blandy's avatar
Jim Blandy committed
302 303 304 305 306
    }

  if (echo_area_glyphs || minibuf_level == 0)
    {
      vpos = XFASTINT (XWINDOW (minibuf_window)->top);
Jim Blandy's avatar
Jim Blandy committed
307
      get_display_line (f, vpos, 0);
Jim Blandy's avatar
Jim Blandy committed
308 309
      display_string (XWINDOW (minibuf_window), vpos,
		      echo_area_glyphs ? echo_area_glyphs : "",
Jim Blandy's avatar
Jim Blandy committed
310
		      0, 0, 0, FRAME_WIDTH (f));
Jim Blandy's avatar
Jim Blandy committed
311 312

      /* If desired cursor location is on this line, put it at end of text */
Jim Blandy's avatar
Jim Blandy committed
313 314
      if (FRAME_CURSOR_Y (f) == vpos)
	FRAME_CURSOR_X (f) = FRAME_DESIRED_GLYPHS (f)->used[vpos];
Jim Blandy's avatar
Jim Blandy committed
315 316 317 318 319 320 321

      /* Fill the rest of the minibuffer window with blank lines.  */
      {
	int i;

	for (i = vpos + 1; i < vpos + XWINDOW (minibuf_window)->height; i++)
	  {
Jim Blandy's avatar
Jim Blandy committed
322
	    get_display_line (f, i, 0);
Jim Blandy's avatar
Jim Blandy committed
323
	    display_string (XWINDOW (minibuf_window), vpos,
Jim Blandy's avatar
Jim Blandy committed
324
			    "", 0, 0, 0, FRAME_WIDTH (f));
Jim Blandy's avatar
Jim Blandy committed
325 326
	  }
      }
Jim Blandy's avatar
Jim Blandy committed
327 328 329 330 331 332 333 334 335 336
    }
  else if (!EQ (minibuf_window, selected_window))
    windows_or_buffers_changed++;

  if (EQ (minibuf_window, selected_window))
    this_line_bufpos = 0;

  previous_echo_glyphs = echo_area_glyphs;
}

Jim Blandy's avatar
Jim Blandy committed
337
/* Do a frame update, taking possible shortcuts into account.
Jim Blandy's avatar
Jim Blandy committed
338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365
   This is the main external entry point for redisplay.

   If the last redisplay displayed an echo area message and that
   message is no longer requested, we clear the echo area
   or bring back the minibuffer if that is in use.

   Everyone would like to have a hook here to call eval,
   but that cannot be done safely without a lot of changes elsewhere.
   This can be called from signal handlers; with alarms set up;
   or with synchronous processes running.
   See the function `echo' in keyboard.c.
   See Fcall_process; if you called it from here, it could be
   entered recursively.  */

void
redisplay ()
{
  register struct window *w = XWINDOW (selected_window);
  register int pause;
  int must_finish = 0;
  int all_windows;
  register int tlbufpos, tlendpos;
  struct position pos;
  extern int input_pending;

  if (noninteractive)
    return;

366 367 368 369 370 371 372 373 374 375 376 377
  /* Set the visible flags for all frames.
     Do this before checking for resized or garbaged frames; they want
     to know if their frames are visible.
     See the comment in frame.h for FRAME_SAMPLE_VISIBILITY.  */
  {
    Lisp_Object tail;
    FRAME_PTR f;

    FOR_EACH_FRAME (tail, f)
      FRAME_SAMPLE_VISIBILITY (f);
  }

Jim Blandy's avatar
Jim Blandy committed
378
  /* Notice any pending interrupt request to change frame size.  */
Jim Blandy's avatar
Jim Blandy committed
379 380
  do_pending_window_change ();

Jim Blandy's avatar
Jim Blandy committed
381
  if (frame_garbaged)
Jim Blandy's avatar
Jim Blandy committed
382 383
    {
      Fredraw_display ();
Jim Blandy's avatar
Jim Blandy committed
384
      frame_garbaged = 0;
Jim Blandy's avatar
Jim Blandy committed
385 386
    }

Jim Blandy's avatar
Jim Blandy committed
387
  /* Normally the message* functions will have already displayed and
Jim Blandy's avatar
Jim Blandy committed
388
     updated the echo area, but the frame may have been trashed, or
Jim Blandy's avatar
Jim Blandy committed
389 390
     the update may have been preempted, so display the echo area
     again here.  */
Jim Blandy's avatar
Jim Blandy committed
391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408
  if (echo_area_glyphs || previous_echo_glyphs)
    {
      echo_area_display ();
      must_finish = 1;
    }

  if (clip_changed || windows_or_buffers_changed)
    update_mode_lines++;

  /* Detect case that we need to write a star in the mode line.  */
  if (XFASTINT (w->last_modified) < MODIFF
      && XFASTINT (w->last_modified) <= current_buffer->save_modified)
    {
      w->update_mode_line = Qt;
      if (buffer_shared > 1)
	update_mode_lines++;
    }

Jim Blandy's avatar
Jim Blandy committed
409
  FRAME_SCROLL_BOTTOM_VPOS (XFRAME (w->frame)) = -1;
Jim Blandy's avatar
Jim Blandy committed
410 411 412 413 414

  all_windows = update_mode_lines || buffer_shared > 1;

  /* If specs for an arrow have changed, do thorough redisplay
     to ensure we remove any arrow that should no longer exist.  */
415 416
  if (! EQ (Voverlay_arrow_position, last_arrow_position)
      || ! EQ (Voverlay_arrow_string, last_arrow_string))
Jim Blandy's avatar
Jim Blandy committed
417 418 419 420
    all_windows = 1, clip_changed = 1;

  tlbufpos = this_line_bufpos;
  tlendpos = this_line_endpos;
Jim Blandy's avatar
Jim Blandy committed
421
  if (!all_windows && tlbufpos > 0 && NILP (w->update_mode_line)
Jim Blandy's avatar
Jim Blandy committed
422
      && FRAME_VISIBLE_P (XFRAME (w->frame))
Jim Blandy's avatar
Jim Blandy committed
423 424 425
      /* Make sure recorded data applies to current buffer, etc */
      && this_line_buffer == current_buffer
      && current_buffer == XBUFFER (w->buffer)
Jim Blandy's avatar
Jim Blandy committed
426
      && NILP (w->force_start)
Jim Blandy's avatar
Jim Blandy committed
427 428 429 430 431 432 433 434
      /* Point must be on the line that we have info recorded about */
      && point >= tlbufpos
      && point <= Z - tlendpos
      /* All text outside that line, including its final newline,
	 must be unchanged */
      && (XFASTINT (w->last_modified) >= MODIFF
	  || (beg_unchanged >= tlbufpos - 1
	      && GPT >= tlbufpos
Jim Blandy's avatar
Jim Blandy committed
435 436 437 438 439 440 441
	      /* If selective display, can't optimize
		 if the changes start at the beginning of the line.  */
	      && ((XTYPE (current_buffer->selective_display) == Lisp_Int
		   && XINT (current_buffer->selective_display) > 0
		   ? (beg_unchanged >= tlbufpos
		      && GPT > tlbufpos)
		   : 1))
Jim Blandy's avatar
Jim Blandy committed
442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461
	      && end_unchanged >= tlendpos
	      && Z - GPT >= tlendpos)))
    {
      if (tlbufpos > BEGV && FETCH_CHAR (tlbufpos - 1) != '\n'
	  && (tlbufpos == ZV
	      || FETCH_CHAR (tlbufpos) == '\n'))
	/* Former continuation line has disappeared by becoming empty */
	goto cancel;
      else if (XFASTINT (w->last_modified) < MODIFF
	       || MINI_WINDOW_P (w))
	{
	  cursor_vpos = -1;
	  overlay_arrow_seen = 0;
	  display_text_line (w, tlbufpos, this_line_vpos, this_line_start_hpos,
			     pos_tab_offset (w, tlbufpos));
	  /* If line contains point, is not continued,
		 and ends at same distance from eob as before, we win */
	  if (cursor_vpos >= 0 && this_line_bufpos
	      && this_line_endpos == tlendpos)
	    {
Jim Blandy's avatar
Jim Blandy committed
462
	      if (XFASTINT (w->width) != FRAME_WIDTH (XFRAME (WINDOW_FRAME (w))))
Jim Blandy's avatar
Jim Blandy committed
463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482
		preserve_other_columns (w);
	      goto update;
	    }
	  else
	    goto cancel;
	}
      else if (point == XFASTINT (w->last_point))
	{
	  if (!must_finish)
	    {
	      do_pending_window_change ();
	      return;
	    }
	  goto update;
	}
      else
	{
	  pos = *compute_motion (tlbufpos, 0,
				 XINT (w->hscroll) ? 1 - XINT (w->hscroll) : 0,
				 point, 2, - (1 << (SHORTBITS - 1)),
483
				 window_internal_width (w) - 1,
Jim Blandy's avatar
Jim Blandy committed
484 485
				 XINT (w->hscroll),
				 pos_tab_offset (w, tlbufpos));
Jim Blandy's avatar
Jim Blandy committed
486 487
	  if (pos.vpos < 1)
	    {
Jim Blandy's avatar
Jim Blandy committed
488
	      FRAME_CURSOR_X (selected_frame)
Jim Blandy's avatar
Jim Blandy committed
489
		= XFASTINT (w->left) + max (pos.hpos, 0);
Jim Blandy's avatar
Jim Blandy committed
490
	      FRAME_CURSOR_Y (selected_frame) = this_line_vpos;
Jim Blandy's avatar
Jim Blandy committed
491 492 493 494 495 496 497
	      goto update;
	    }
	  else
	    goto cancel;
	}
    cancel:
      /* Text changed drastically or point moved off of line */
Jim Blandy's avatar
Jim Blandy committed
498
      cancel_line (this_line_vpos, selected_frame);
Jim Blandy's avatar
Jim Blandy committed
499 500 501 502 503 504 505 506
    }

  this_line_bufpos = 0;
  all_windows |= buffer_shared > 1;

  if (all_windows)
    {
      Lisp_Object tail;
507
      FRAME_PTR f;
Jim Blandy's avatar
Jim Blandy committed
508 509

      /* Recompute # windows showing selected buffer.
Jim Blandy's avatar
Jim Blandy committed
510
	 This will be incremented each time such a window is displayed.  */
Jim Blandy's avatar
Jim Blandy committed
511 512
      buffer_shared = 0;

513
      FOR_EACH_FRAME (tail, f)
514 515 516
	{
	  /* Mark all the scrollbars to be removed; we'll redeem the ones
	     we want when we redisplay their windows.  */
517
	  if (condemn_scrollbars_hook)
518 519 520 521 522 523 524
	    (*condemn_scrollbars_hook) (f);

	  if (FRAME_VISIBLE_P (f))
	    redisplay_windows (FRAME_ROOT_WINDOW (f));

	  /* Any scrollbars which redisplay_windows should have nuked
	     should now go away.  */
525
	  if (judge_scrollbars_hook)
526 527
	    (*judge_scrollbars_hook) (f);
	}
Jim Blandy's avatar
Jim Blandy committed
528
    }
Jim Blandy's avatar
Jim Blandy committed
529
  else if (FRAME_VISIBLE_P (selected_frame))
Jim Blandy's avatar
Jim Blandy committed
530 531
    {
      redisplay_window (selected_window, 1);
Jim Blandy's avatar
Jim Blandy committed
532
      if (XFASTINT (w->width) != FRAME_WIDTH (selected_frame))
Jim Blandy's avatar
Jim Blandy committed
533 534 535 536 537 538 539 540 541 542 543
	preserve_other_columns (w);
    }

update: 
  /* Prevent various kinds of signals during display update.
     stdio is not robust about handling signals,
     which can cause an apparent I/O error.  */
  if (interrupt_input)
    unrequest_sigio ();
  stop_polling ();

Jim Blandy's avatar
Jim Blandy committed
544
#ifdef MULTI_FRAME
Jim Blandy's avatar
Jim Blandy committed
545 546 547 548 549 550
  if (all_windows)
    {
      Lisp_Object tail;

      pause = 0;

Jim Blandy's avatar
Jim Blandy committed
551
      for (tail = Vframe_list; CONSP (tail); tail = XCONS (tail)->cdr)
Jim Blandy's avatar
Jim Blandy committed
552
	{
Jim Blandy's avatar
Jim Blandy committed
553
	  FRAME_PTR f;
Jim Blandy's avatar
Jim Blandy committed
554

Jim Blandy's avatar
Jim Blandy committed
555
	  if (XTYPE (XCONS (tail)->car) != Lisp_Frame)
Jim Blandy's avatar
Jim Blandy committed
556 557
	    continue;

Jim Blandy's avatar
Jim Blandy committed
558
	  f = XFRAME (XCONS (tail)->car);
559
	  if (FRAME_VISIBLE_P (f))
Jim Blandy's avatar
Jim Blandy committed
560
	    {
Jim Blandy's avatar
Jim Blandy committed
561
	      pause |= update_frame (f, 0, 0);
Jim Blandy's avatar
Jim Blandy committed
562
	      if (!pause)
Jim Blandy's avatar
Jim Blandy committed
563
		mark_window_display_accurate (f->root_window, 1);
Jim Blandy's avatar
Jim Blandy committed
564 565 566 567
	    }
	}
    }
  else
Jim Blandy's avatar
Jim Blandy committed
568
#endif /* MULTI_FRAME */
Jim Blandy's avatar
Jim Blandy committed
569
    {
Jim Blandy's avatar
Jim Blandy committed
570 571
      if (FRAME_VISIBLE_P (selected_frame))
	pause = update_frame (selected_frame, 0, 0);
572

Jim Blandy's avatar
Jim Blandy committed
573
      /* We may have called echo_area_display at the top of this
Jim Blandy's avatar
Jim Blandy committed
574 575 576
	 function.  If the echo area is on another frame, that may
	 have put text on a frame other than the selected one, so the
	 above call to update_frame would not have caught it.  Catch
Jim Blandy's avatar
Jim Blandy committed
577 578
	 it here.  */
      {
Jim Blandy's avatar
Jim Blandy committed
579 580
	FRAME_PTR mini_frame =
	  XFRAME (WINDOW_FRAME (XWINDOW (minibuf_window)));
Jim Blandy's avatar
Jim Blandy committed
581
	
Jim Blandy's avatar
Jim Blandy committed
582 583
	if (mini_frame != selected_frame)
	  pause |= update_frame (mini_frame, 0, 0);
Jim Blandy's avatar
Jim Blandy committed
584
      }
Jim Blandy's avatar
Jim Blandy committed
585
    }
Jim Blandy's avatar
Jim Blandy committed
586

Jim Blandy's avatar
Jim Blandy committed
587
  /* If frame does not match, prevent doing single-line-update next time.
Jim Blandy's avatar
Jim Blandy committed
588 589 590 591
     Also, don't forget to check every line to update the arrow.  */
  if (pause)
    {
      this_line_bufpos = 0;
Jim Blandy's avatar
Jim Blandy committed
592
      if (!NILP (last_arrow_position))
Jim Blandy's avatar
Jim Blandy committed
593 594 595 596
	{
	  last_arrow_position = Qt;
	  last_arrow_string = Qt;
	}
Jim Blandy's avatar
Jim Blandy committed
597
      /* If we pause after scrolling, some lines in current_frame
Jim Blandy's avatar
Jim Blandy committed
598 599 600
	 may be null, so preserve_other_columns won't be able to
	 preserve all the vertical-bar separators.  So, avoid using it
	 in that case.  */
Jim Blandy's avatar
Jim Blandy committed
601
      if (XFASTINT (w->width) != FRAME_WIDTH (selected_frame))
Jim Blandy's avatar
Jim Blandy committed
602 603 604
	update_mode_lines = 1;
    }

Jim Blandy's avatar
Jim Blandy committed
605
  /* Now text on frame agrees with windows, so
Jim Blandy's avatar
Jim Blandy committed
606 607 608 609 610 611 612 613 614 615 616 617 618
     put info into the windows for partial redisplay to follow */

  if (!pause)
    {
      register struct buffer *b = XBUFFER (w->buffer);

      blank_end_of_window = 0;
      clip_changed = 0;
      unchanged_modified = BUF_MODIFF (b);
      beg_unchanged = BUF_GPT (b) - BUF_BEG (b);
      end_unchanged = BUF_Z (b) - BUF_GPT (b);

      XFASTINT (w->last_point) = BUF_PT (b);
Jim Blandy's avatar
Jim Blandy committed
619 620
      XFASTINT (w->last_point_x) = FRAME_CURSOR_X (selected_frame);
      XFASTINT (w->last_point_y) = FRAME_CURSOR_Y (selected_frame);
Jim Blandy's avatar
Jim Blandy committed
621 622

      if (all_windows)
623
	mark_window_display_accurate (FRAME_ROOT_WINDOW (selected_frame), 1);
Jim Blandy's avatar
Jim Blandy committed
624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646
      else
	{
	  w->update_mode_line = Qnil;
	  XFASTINT (w->last_modified) = BUF_MODIFF (b);
	  w->window_end_valid = Qt;
	  last_arrow_position = Voverlay_arrow_position;
	  last_arrow_string = Voverlay_arrow_string;
	}
      update_mode_lines = 0;
      windows_or_buffers_changed = 0;
    }

  /* Start SIGIO interrupts coming again.
     Having them off during the code above
     makes it less likely one will discard output,
     but not impossible, since there might be stuff
     in the system buffer here.
     But it is much hairier to try to do anything about that.  */

  if (interrupt_input)
    request_sigio ();
  start_polling ();

Jim Blandy's avatar
Jim Blandy committed
647
  /* Change frame size now if a change is pending.  */
Jim Blandy's avatar
Jim Blandy committed
648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677
  do_pending_window_change ();
}

/* Redisplay, but leave alone any recent echo area message
   unless another message has been requested in its place.

   This is useful in situations where you need to redisplay but no
   user action has occurred, making it inappropriate for the message
   area to be cleared.  See tracking_off and
   wait_reading_process_input for examples of these situations.  */

redisplay_preserve_echo_area ()
{
  if (echo_area_glyphs == 0 && previous_echo_glyphs != 0)
    {
      echo_area_glyphs = previous_echo_glyphs;
      redisplay ();
      echo_area_glyphs = 0;
    }
  else
    redisplay ();
}

void
mark_window_display_accurate (window, flag)
     Lisp_Object window;
     int flag;
{
  register struct window *w;

Jim Blandy's avatar
Jim Blandy committed
678
  for (;!NILP (window); window = w->next)
Jim Blandy's avatar
Jim Blandy committed
679
    {
680
      if (XTYPE (window) != Lisp_Window) abort ();
Jim Blandy's avatar
Jim Blandy committed
681 682
      w = XWINDOW (window);

Jim Blandy's avatar
Jim Blandy committed
683
      if (!NILP (w->buffer))
Jim Blandy's avatar
Jim Blandy committed
684 685 686 687 688 689 690
	XFASTINT (w->last_modified)
	  = !flag ? 0
	    : XBUFFER (w->buffer) == current_buffer
	      ? MODIFF : BUF_MODIFF (XBUFFER (w->buffer));
      w->window_end_valid = Qt;
      w->update_mode_line = Qnil;

Jim Blandy's avatar
Jim Blandy committed
691
      if (!NILP (w->vchild))
Jim Blandy's avatar
Jim Blandy committed
692
	mark_window_display_accurate (w->vchild, flag);
Jim Blandy's avatar
Jim Blandy committed
693
      if (!NILP (w->hchild))
Jim Blandy's avatar
Jim Blandy committed
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715
	mark_window_display_accurate (w->hchild, flag);
    }

  if (flag)
    {
      last_arrow_position = Voverlay_arrow_position;
      last_arrow_string = Voverlay_arrow_string;
    }
  else
    {
      /* t is unequal to any useful value of Voverlay_arrow_... */
      last_arrow_position = Qt;
      last_arrow_string = Qt;
    }
}

int do_id = 1;

static void
redisplay_windows (window)
     Lisp_Object window;
{
Jim Blandy's avatar
Jim Blandy committed
716
  for (; !NILP (window); window = XWINDOW (window)->next)
Jim Blandy's avatar
Jim Blandy committed
717 718 719 720 721 722 723 724 725
    redisplay_window (window, 0);
}

static void
redisplay_window (window, just_this_one)
     Lisp_Object window;
     int just_this_one;
{
  register struct window *w = XWINDOW (window);
726
  FRAME_PTR f = XFRAME (WINDOW_FRAME (w));
Jim Blandy's avatar
Jim Blandy committed
727 728 729
  int height;
  register int lpoint = point;
  struct buffer *old = current_buffer;
730
  register int width = window_internal_width (w) - 1;
Jim Blandy's avatar
Jim Blandy committed
731 732 733
  register int startp;
  register int hscroll = XINT (w->hscroll);
  struct position pos;
734
  int opoint = point;
Jim Blandy's avatar
Jim Blandy committed
735 736 737
  int tem;
  int window_needs_modeline;

Jim Blandy's avatar
Jim Blandy committed
738
  if (FRAME_HEIGHT (f) == 0) abort (); /* Some bug zeros some core */
Jim Blandy's avatar
Jim Blandy committed
739 740 741

  /* If this is a combination window, do its children; that's all.  */

Jim Blandy's avatar
Jim Blandy committed
742
  if (!NILP (w->vchild))
Jim Blandy's avatar
Jim Blandy committed
743 744 745 746
    {
      redisplay_windows (w->vchild);
      return;
    }
Jim Blandy's avatar
Jim Blandy committed
747
  if (!NILP (w->hchild))
Jim Blandy's avatar
Jim Blandy committed
748 749 750 751
    {
      redisplay_windows (w->hchild);
      return;
    }
Jim Blandy's avatar
Jim Blandy committed
752
  if (NILP (w->buffer))
Jim Blandy's avatar
Jim Blandy committed
753
    abort ();
Jim Blandy's avatar
Jim Blandy committed
754 755 756 757 758 759 760 761 762
  
  height = window_internal_height (w);

  if (MINI_WINDOW_P (w))
    {
      if (w == XWINDOW (minibuf_window))
	{
	  if (echo_area_glyphs)
	    /* We've already displayed the echo area glyphs, if any.  */
763
	    goto finish_scrollbars;
Jim Blandy's avatar
Jim Blandy committed
764 765 766 767 768
	}
      else
	{
	  /* This is a minibuffer, but it's not the currently active one, so
	     clear it.  */
Jim Blandy's avatar
Jim Blandy committed
769
	  int vpos = XFASTINT (XWINDOW (FRAME_MINIBUF_WINDOW (f))->top);
Jim Blandy's avatar
Jim Blandy committed
770 771 772 773
	  int i;

	  for (i = 0; i < height; i++)
	    {
Jim Blandy's avatar
Jim Blandy committed
774
	      get_display_line (f, vpos + i, 0);
Jim Blandy's avatar
Jim Blandy committed
775 776 777
	      display_string (w, vpos + i, "", 0, 0, 0, width);
	    }
	  
778
	  goto finish_scrollbars;
Jim Blandy's avatar
Jim Blandy committed
779 780
	}
    }
Jim Blandy's avatar
Jim Blandy committed
781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803

  if (update_mode_lines)
    w->update_mode_line = Qt;

  /* Otherwise set up data on this window; select its buffer and point value */

  current_buffer = XBUFFER (w->buffer);
  opoint = point;

  /* Count number of windows showing the selected buffer.  */

  if (!just_this_one
      && current_buffer == XBUFFER (XWINDOW (selected_window)->buffer))
    buffer_shared++;

  /* POINT refers normally to the selected window.
     For any other window, set up appropriate value.  */

  if (!EQ (window, selected_window))
    {
      SET_PT (marker_position (w->pointm));
      if (point < BEGV)
	{
Jim Blandy's avatar
Jim Blandy committed
804
	  SET_PT (BEGV);
Jim Blandy's avatar
Jim Blandy committed
805 806 807 808
	  Fset_marker (w->pointm, make_number (point), Qnil);
	}
      else if (point > (ZV - 1))
	{
Jim Blandy's avatar
Jim Blandy committed
809
	  SET_PT (ZV);
Jim Blandy's avatar
Jim Blandy committed
810 811 812 813 814 815 816 817 818 819
	  Fset_marker (w->pointm, make_number (point), Qnil);
	}
    }

  /* If window-start is screwed up, choose a new one.  */
  if (XMARKER (w->start)->buffer != current_buffer)
    goto recenter;

  startp = marker_position (w->start);

Jim Blandy's avatar
Jim Blandy committed
820 821
  /* Handle case where place to start displaying has been specified,
     unless the specified location is outside the visible range.  */
Jim Blandy's avatar
Jim Blandy committed
822
  if (!NILP (w->force_start))
Jim Blandy's avatar
Jim Blandy committed
823 824 825 826
    {
      w->update_mode_line = Qt;
      w->force_start = Qnil;
      XFASTINT (w->last_modified) = 0;
Jim Blandy's avatar
Jim Blandy committed
827 828
      if (startp < BEGV) startp = BEGV;
      if (startp > ZV)   startp = ZV;
Jim Blandy's avatar
Jim Blandy committed
829 830 831 832 833 834 835 836 837 838 839 840 841
      try_window (window, startp);
      if (cursor_vpos < 0)
	{
	  /* If point does not appear, move point so it does appear */
	  pos = *compute_motion (startp, 0,
				((EQ (window, minibuf_window) && startp == 1)
				 ? minibuf_prompt_width : 0)
				+
				(hscroll ? 1 - hscroll : 0),
				ZV, height / 2,
				- (1 << (SHORTBITS - 1)),
				width, hscroll, pos_tab_offset (w, startp));
	  SET_PT (pos.bufpos);
Jim Blandy's avatar
Jim Blandy committed
842
	  if (w != XWINDOW (FRAME_SELECTED_WINDOW (f)))
Jim Blandy's avatar
Jim Blandy committed
843 844 845 846
	    Fset_marker (w->pointm, make_number (point), Qnil);
	  else
	    {
	      lpoint = point;
Jim Blandy's avatar
Jim Blandy committed
847 848
	      FRAME_CURSOR_X (f) = max (0, pos.hpos) + XFASTINT (w->left);
	      FRAME_CURSOR_Y (f) = pos.vpos + XFASTINT (w->top);
Jim Blandy's avatar
Jim Blandy committed
849 850 851 852 853 854
	    }
	}
      goto done;
    }

  /* Handle case where text has not changed, only point,
Jim Blandy's avatar
Jim Blandy committed
855
     and it has not moved off the frame */
Jim Blandy's avatar
Jim Blandy committed
856 857 858 859 860 861 862 863 864 865

  /* This code is not used for minibuffer for the sake of
     the case of redisplaying to replace an echo area message;
     since in that case the minibuffer contents per se are usually unchanged.
     This code is of no real use in the minibuffer since
     the handling of this_line_bufpos, etc.,
     in redisplay handles the same cases.  */

  if (XFASTINT (w->last_modified) >= MODIFF
      && point >= startp && !clip_changed
Jim Blandy's avatar
Jim Blandy committed
866
      && (just_this_one || XFASTINT (w->width) == FRAME_WIDTH (f))
Jim Blandy's avatar
Jim Blandy committed
867 868 869 870 871 872 873 874
      && !EQ (window, minibuf_window))
    {
      pos = *compute_motion (startp, 0, (hscroll ? 1 - hscroll : 0),
			    point, height + 1, 10000, width, hscroll,
			    pos_tab_offset (w, startp));

      if (pos.vpos < height)
	{
Jim Blandy's avatar
Jim Blandy committed
875 876
	  /* Ok, point is still on frame */
	  if (w == XWINDOW (FRAME_SELECTED_WINDOW (f)))
Jim Blandy's avatar
Jim Blandy committed
877 878
	    {
	      /* These variables are supposed to be origin 1 */
Jim Blandy's avatar
Jim Blandy committed
879 880
	      FRAME_CURSOR_X (f) = max (0, pos.hpos) + XFASTINT (w->left);
	      FRAME_CURSOR_Y (f) = pos.vpos + XFASTINT (w->top);
Jim Blandy's avatar
Jim Blandy committed
881 882 883
	    }
	  /* This doesn't do the trick, because if a window to the right of
	     this one must be redisplayed, this does nothing because there
Jim Blandy's avatar
Jim Blandy committed
884
	     is nothing in DesiredFrame yet, and then the other window is
Jim Blandy's avatar
Jim Blandy committed
885
	     redisplayed, making likes that are empty in this window's columns.
Jim Blandy's avatar
Jim Blandy committed
886
	     if (XFASTINT (w->width) != FRAME_WIDTH (f))
Jim Blandy's avatar
Jim Blandy committed
887 888 889 890 891 892 893 894 895
	     preserve_my_columns (w);
	     */
	  goto done;
	}
      /* Don't bother trying redisplay with same start;
	we already know it will lose */
    }
  /* If current starting point was originally the beginning of a line
     but no longer is, find a new starting point.  */
Jim Blandy's avatar
Jim Blandy committed
896
  else if (!NILP (w->start_at_line_beg)
Jim Blandy's avatar
Jim Blandy committed
897 898 899 900 901 902 903 904 905 906 907
	   && !(startp == BEGV
		|| FETCH_CHAR (startp - 1) == '\n'))
    {
      goto recenter;
    }
  else if (just_this_one && !MINI_WINDOW_P (w)
	   && point >= startp
	   && XFASTINT (w->last_modified)
	   && ! EQ (w->window_end_valid, Qnil)
	   && do_id && !clip_changed
	   && !blank_end_of_window
Jim Blandy's avatar
Jim Blandy committed
908
	   && XFASTINT (w->width) == FRAME_WIDTH (f)
Jim Blandy's avatar
Jim Blandy committed
909 910
	   && EQ (last_arrow_position, Voverlay_arrow_position)
	   && EQ (last_arrow_string, Voverlay_arrow_string)
Jim Blandy's avatar
Jim Blandy committed
911
	   && (tem = try_window_id (FRAME_SELECTED_WINDOW (f)))
Jim Blandy's avatar
Jim Blandy committed
912 913 914 915 916 917 918 919 920 921 922
	   && tem != -2)
    {
      /* tem > 0 means success.  tem == -1 means choose new start.
	 tem == -2 means try again with same start,
	  and nothing but whitespace follows the changed stuff.
	 tem == 0 means try again with same start.  */
      if (tem > 0)
	goto done;
    }
  else if (startp >= BEGV && startp <= ZV
	   /* Avoid starting display at end of buffer! */
Jim Blandy's avatar
Jim Blandy committed
923
	   && (startp < ZV || startp == BEGV
Jim Blandy's avatar
Jim Blandy committed
924 925 926
	       || (XFASTINT (w->last_modified) >= MODIFF)))
    {
      /* Try to redisplay starting at same place as before */
Jim Blandy's avatar
Jim Blandy committed
927
      /* If point has not moved off frame, accept the results */
Jim Blandy's avatar
Jim Blandy committed
928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
      try_window (window, startp);
      if (cursor_vpos >= 0)
	goto done;
      else
	cancel_my_columns (w);
    }

  XFASTINT (w->last_modified) = 0;
  w->update_mode_line = Qt;

  /* Try to scroll by specified few lines */

  if (scroll_step && !clip_changed)
    {
      if (point > startp)
	{
	  pos = *vmotion (Z - XFASTINT (w->window_end_pos),
			  scroll_step, width, hscroll, window);
	  if (pos.vpos >= height)
	    goto scroll_fail;
	}

      pos = *vmotion (startp, point < startp ? - scroll_step : scroll_step,
		      width, hscroll, window);

      if (point >= pos.bufpos)
	{
	  try_window (window, pos.bufpos);
	  if (cursor_vpos >= 0)
	    goto done;
	  else
	    cancel_my_columns (w);
	}
    scroll_fail: ;
    }

  /* Finally, just choose place to start which centers point */

recenter:
  pos = *vmotion (point, - height / 2, width, hscroll, window);
  try_window (window, pos.bufpos);

  startp = marker_position (w->start);
  w->start_at_line_beg = 
    (startp == BEGV || FETCH_CHAR (startp - 1) == '\n') ? Qt : Qnil;

done:
  /* If window not full width, must redo its mode line
     if the window to its side is being redone */
Jim Blandy's avatar
Jim Blandy committed
977
  if ((!NILP (w->update_mode_line)
Jim Blandy's avatar
Jim Blandy committed
978
       || (!just_this_one && width < FRAME_WIDTH (f) - 1))
Jim Blandy's avatar
Jim Blandy committed
979 980 981
      && height != XFASTINT (w->height))
    display_mode_line (w);

982
 finish_scrollbars:
983 984
  if (FRAME_HAS_VERTICAL_SCROLLBARS (f))
    {
985
      int start, end, whole;
986

987 988 989 990 991 992 993 994 995 996 997 998 999
      /* Calculate the start and end positions for the current window.
	 Note that minibuffers sometimes aren't displaying any text.  */
      if (! MINI_WINDOW_P (w)
	  || (w == XWINDOW (minibuf_window) && ! echo_area_glyphs))
	{
	  start = startp;
	  /* I don't think this is guaranteed to be right.  For the
	     moment, we'll pretend it is.  */
	  end = Z - XINT (w->window_end_pos);
	  whole = Z - BEG;
	}
      else
	start = end = whole = 0;
1000 1001

      /* Indicate what this scrollbar ought to be displaying now.  */
1002
      (*set_vertical_scrollbar_hook) (w, end - start, whole, start - 1);
1003 1004 1005

      /* Note that we actually used the scrollbar attached to this window,
	 so it shouldn't be deleted at the end of redisplay.  */
1006
      (*redeem_scrollbar_hook) (w);
1007
    }
1008 1009 1010 1011

  SET_PT (opoint);
  current_buffer = old;
  SET_PT (lpoint);
Jim Blandy's avatar
Jim Blandy committed
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025
}

/* Do full redisplay on one window, starting at position `pos'. */

static void
try_window (window, pos)
     Lisp_Object window;
     register int pos;
{
  register struct window *w = XWINDOW (window);
  register int height = window_internal_height (w);
  register int vpos = XFASTINT (w->top);
  register int last_text_vpos = vpos;
  int tab_offset = pos_tab_offset (w, pos);
Jim Blandy's avatar
Jim Blandy committed
1026
  FRAME_PTR f = XFRAME (w->frame);
1027
  int width = window_internal_width (w) - 1;
Jim Blandy's avatar
Jim Blandy committed
1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048
  struct position val;

  Fset_marker (w->start, make_number (pos), Qnil);
  cursor_vpos = -1;
  overlay_arrow_seen = 0;
  val.hpos = XINT (w->hscroll) ? 1 - XINT (w->hscroll) : 0;

  while (--height >= 0)
    {
      val = *display_text_line (w, pos, vpos, val.hpos, tab_offset);
      tab_offset += width;
      if (val.vpos) tab_offset = 0;
      vpos++;
      if (pos != val.bufpos)
	last_text_vpos
	  /* Next line, unless prev line ended in end of buffer with no cr */
	  = vpos - (val.vpos && FETCH_CHAR (val.bufpos - 1) != '\n');
      pos = val.bufpos;
    }

  /* If last line is continued in middle of character,
Jim Blandy's avatar
Jim Blandy committed
1049
     include the split character in the text considered on the frame */
Jim Blandy's avatar
Jim Blandy committed
1050 1051 1052
  if (val.hpos < (XINT (w->hscroll) ? 1 - XINT (w->hscroll) : 0))
    pos++;

Jim Blandy's avatar
Jim Blandy committed
1053
  /* If bottom just moved off end of frame, change mode line percentage.  */
Jim Blandy's avatar
Jim Blandy committed
1054 1055 1056 1057
  if (XFASTINT (w->window_end_pos) == 0
      && Z != pos)
    w->update_mode_line = Qt;

Jim Blandy's avatar
Jim Blandy committed
1058
  /* Say where last char on frame will be, once redisplay is finished.  */
Jim Blandy's avatar
Jim Blandy committed
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078
  XFASTINT (w->window_end_pos) = Z - pos;
  XFASTINT (w->window_end_vpos) = last_text_vpos - XFASTINT (w->top);
  /* But that is not valid info until redisplay finishes.  */
  w->window_end_valid = Qnil;
}

/* Try to redisplay when buffer is modified locally,
 computing insert/delete line to preserve text outside
 the bounds of the changes.
 Return 1 if successful, 0 if if cannot tell what to do,
 or -1 to tell caller to find a new window start,
 or -2 to tell caller to do normal redisplay with same window start.  */

static int
try_window_id (window)
     Lisp_Object window;
{
  int pos;
  register struct window *w = XWINDOW (window);
  register int height = window_internal_height (w);
Jim Blandy's avatar
Jim Blandy committed
1079
  FRAME_PTR f = XFRAME (w->frame);
Jim Blandy's avatar
Jim Blandy committed
1080 1081
  int top = XFASTINT (w->top);
  int start = marker_position (w->start);
1082
  int width = window_internal_width (w) - 1;
Jim Blandy's avatar
Jim Blandy committed
1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104
  int hscroll = XINT (w->hscroll);
  int lmargin = hscroll > 0 ? 1 - hscroll : 0;
  register int vpos;
  register int i, tem;
  int last_text_vpos = 0;
  int stop_vpos;

  struct position val, bp, ep, xp, pp;
  int scroll_amount = 0;
  int delta;
  int tab_offset, epto;

  if (GPT - BEG < beg_unchanged)
    beg_unchanged = GPT - BEG;
  if (Z - GPT < end_unchanged)
    end_unchanged = Z - GPT;

  if (beg_unchanged + 1 < start)
    return 0;			/* Give up if changes go above top of window */

  /* Find position before which nothing is changed.  */
  bp = *compute_motion (start, 0, lmargin,
Jim Blandy's avatar
Jim Blandy committed
1105
			beg_unchanged + 1, height + 1, 0, width, hscroll,
Jim Blandy's avatar
Jim Blandy committed
1106 1107
			pos_tab_offset (w, start));
  if (bp.vpos >= height)
Jim Blandy's avatar
Jim Blandy committed
1108 1109 1110
    {
      if (point < bp.bufpos && !bp.contin)
	{
Jim Blandy's avatar
Jim Blandy committed
1111 1112
	  /* All changes are below the frame, and point is on the frame.
	     We don't need to change the frame at all.
Jim Blandy's avatar
Jim Blandy committed
1113 1114
	     But we need to update window_end_pos to account for
	     any change in buffer size.  */
Jim Blandy's avatar
Jim Blandy committed
1115 1116 1117
	  bp = *compute_motion (start, 0, lmargin,
				Z, height, 0,
				width, hscroll, pos_tab_offset (w, start));
Jim Blandy's avatar
Jim Blandy committed
1118 1119 1120 1121 1122 1123
	  XFASTINT (w->window_end_vpos) = height;
	  XFASTINT (w->window_end_pos) = Z - bp.bufpos;
	  return 1;
	}
      return 0;
    }
Jim Blandy's avatar
Jim Blandy committed
1124 1125 1126

  vpos = bp.vpos;

Jim Blandy's avatar
Jim Blandy committed
1127
  /* Find beginning of that frame line.  Must display from there.  */
Jim Blandy's avatar
Jim Blandy committed
1128 1129 1130 1131 1132 1133 1134 1135
  bp = *vmotion (bp.bufpos, 0, width, hscroll, window);

  pos = bp.bufpos;
  val.hpos = lmargin;
  if (pos < start)
    return -1;

  /* If about to start displaying at the beginning of a continuation line,
Jim Blandy's avatar
Jim Blandy committed
1136
     really start with previous frame line, in case it was not
Jim Blandy's avatar
Jim Blandy committed
1137
     continued when last redisplayed */
Jim Blandy's avatar
Jim Blandy committed
1138 1139 1140 1141 1142 1143
  if ((bp.contin && bp.bufpos - 1 == beg_unchanged && vpos > 0)
      ||
      /* Likewise if we have to worry about selective display.  */
      (XTYPE (current_buffer->selective_display) == Lisp_Int
       && XINT (current_buffer->selective_display) > 0
       && bp.bufpos - 1 == beg_unchanged && vpos > 0))
Jim Blandy's avatar
Jim Blandy committed
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171
    {
      bp = *vmotion (bp.bufpos, -1, width, hscroll, window);
      --vpos;
      pos = bp.bufpos;
    }

  if (bp.contin && bp.hpos != lmargin)
    {
      val.hpos = bp.prevhpos - width + lmargin;
      pos--;
    }

  bp.vpos = vpos;

  /* Find first visible newline after which no more is changed.  */
  tem = find_next_newline (Z - max (end_unchanged, Z - ZV), 1);
  if (XTYPE (current_buffer->selective_display) == Lisp_Int
      && XINT (current_buffer->selective_display) > 0)
    while (tem < ZV - 1
	   && (position_indentation (tem)
	       >= XINT (current_buffer->selective_display)))
      tem = find_next_newline (tem, 1);

  /* Compute the cursor position after that newline.  */
  ep = *compute_motion (pos, vpos, val.hpos, tem,
			height, - (1 << (SHORTBITS - 1)),
			width, hscroll, pos_tab_offset (w, bp.bufpos));

Jim Blandy's avatar
Jim Blandy committed
1172 1173
  /* If changes reach past the text available on the frame,
     just display rest of frame.  */
Jim Blandy's avatar
Jim Blandy committed
1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203
  if (ep.bufpos > Z - XFASTINT (w->window_end_pos))
    stop_vpos = height;
  else
    stop_vpos = ep.vpos;

  /* If no newline before ep, the line ep is on includes some changes
     that must be displayed.  Make sure we don't stop before it.  */
  /* Also, if changes reach all the way until ep.bufpos,
     it is possible that something was deleted after the
     newline before it, so the following line must be redrawn. */
  if (stop_vpos == ep.vpos
      && (ep.bufpos == BEGV
	  || FETCH_CHAR (ep.bufpos - 1) != '\n'
	  || ep.bufpos == Z - end_unchanged))
    stop_vpos = ep.vpos + 1;

  cursor_vpos = -1;
  overlay_arrow_seen = 0;

  /* If changes do not reach to bottom of window,
     figure out how much to scroll the rest of the window */
  if (stop_vpos < height)
    {
      /* Now determine how far up or down the rest of the window has moved */
      epto = pos_tab_offset (w, ep.bufpos);
      xp = *compute_motion (ep.bufpos, ep.vpos, ep.hpos,
			    Z - XFASTINT (w->window_end_pos),
			    10000, 0, width, hscroll, epto);
      scroll_amount = xp.vpos - XFASTINT (w->window_end_vpos);

Jim Blandy's avatar
Jim Blandy committed
1204
      /* Is everything on frame below the changes whitespace?
Jim Blandy's avatar
Jim Blandy committed
1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216
	 If so, no scrolling is really necessary.  */
      for (i = ep.bufpos; i < xp.bufpos; i++)
	{
	  tem = FETCH_CHAR (i);
	  if (tem != ' ' && tem != '\n' && tem != '\t')
	    break;
	}
      if (i == xp.bufpos)
	return -2;

      XFASTINT (w->window_end_vpos) += scroll_amount;

Jim Blandy's avatar
Jim Blandy committed
1217
      /* Before doing any scrolling, verify that point will be on frame. */
Jim Blandy's avatar
Jim Blandy committed
1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246
      if (point > ep.bufpos && !(point <= xp.bufpos && xp.bufpos < height))
	{
	  if (point <= xp.bufpos)
	    {
	      pp = *compute_motion (ep.bufpos, ep.vpos, ep.hpos,
				    point, height, - (1 << (SHORTBITS - 1)),
				    width, hscroll, epto);
	    }
	  else
	    {
	      pp = *compute_motion (xp.bufpos, xp.vpos, xp.hpos,
				    point, height, - (1 << (SHORTBITS - 1)),
				    width, hscroll, pos_tab_offset (w, xp.bufpos));
	    }
	  if (pp.bufpos < point || pp.vpos == height)
	    return 0;
	  cursor_vpos = pp.vpos + top;
	  cursor_hpos = pp.hpos + XFASTINT (w->left);
	}

      if (stop_vpos - scroll_amount >= height
	  || ep.bufpos == xp.bufpos)
	{
	  if (scroll_amount < 0)
	    stop_vpos -= scroll_amount;
	  scroll_amount = 0;
	  /* In this path, we have altered window_end_vpos
	     and not left it negative.
	     We must make sure that, in case display is preempted
Jim Blandy's avatar
Jim Blandy committed
1247
	     before the frame changes to reflect what we do here,
Jim Blandy's avatar
Jim Blandy committed
1248
	     further updates will not come to try_window_id
Jim Blandy's avatar
Jim Blandy committed
1249
	     and assume the frame and window_end_vpos match.  */
Jim Blandy's avatar
Jim Blandy committed
1250 1251 1252 1253 1254 1255 1256 1257
	  blank_end_of_window = 1;
	}
      else if (!scroll_amount)
	{}
      else if (bp.bufpos == Z - end_unchanged)
	{
	  /* If reprinting everything is nearly as fast as scrolling,
	     don't bother scrolling.  Can happen if lines are short.  */
Jim Blandy's avatar
Jim Blandy committed
1258
	  if (scroll_cost (f, bp.vpos + top - scroll_amount,
Jim Blandy's avatar
Jim Blandy committed
1259 1260 1261 1262 1263 1264 1265 1266 1267