Account for focus fading when enabling/disabling reverse video.

Patch by Daniel Hahler.

1 files changed, 3697 insertions, 0 deletions

diff --git a/src/screen.C b/src/screen.C
new file mode 100644
index 0000000..f3c6d57
--- /dev/null
+++ b/src/screen.C
@@ -0,0 +1,3697 @@
+/*---------------------------------------------------------------------------*
+ * File:        screen.C
+ *---------------------------------------------------------------------------*
+ *
+ * Copyright (c) 1997-2001 Geoff Wing <gcw@pobox.com>
+ * Copyright (c) 2003-2007 Marc Lehmann <schmorp@schmorp.de>
+ * Copyright (c) 2015      Emanuele Giaquinta <e.giaquinta@glauco.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *--------------------------------------------------------------------------*/
+
+/*
+ * This file handles _all_ screen updates and selections
+ */
+
+#include "../config.h"          /* NECESSARY */
+#include "rxvt.h"               /* NECESSARY */
+#include "rxvtperl.h"           /* NECESSARY */
+
+#include <inttypes.h>
+
+static inline void
+fill_text (text_t *start, text_t value, int len)
+{
+  while (len--)
+    *start++ = value;
+}
+
+/* ------------------------------------------------------------------------- */
+#define TABSIZE                 8       /* default tab size */
+
+/* ------------------------------------------------------------------------- *
+ *             GENERAL SCREEN AND SELECTION UPDATE ROUTINES                  *
+ * ------------------------------------------------------------------------- */
+#define ZERO_SCROLLBACK()                                              \
+    if (option (Opt_scrollTtyOutput))                                  \
+        view_start = 0
+#define CLEAR_SELECTION()                                              \
+    selection.beg.row = selection.beg.col                              \
+        = selection.end.row = selection.end.col = 0
+#define CLEAR_ALL_SELECTION()                                          \
+    selection.beg.row = selection.beg.col                              \
+        = selection.mark.row = selection.mark.col                      \
+        = selection.end.row = selection.end.col = 0
+
+#define ROW_AND_COL_IS_AFTER(A, B, C, D)                               \
+    (((A) > (C)) || (((A) == (C)) && ((B) > (D))))
+#define ROW_AND_COL_IS_BEFORE(A, B, C, D)                              \
+    (((A) < (C)) || (((A) == (C)) && ((B) < (D))))
+#define ROW_AND_COL_IN_ROW_AFTER(A, B, C, D)                           \
+    (((A) == (C)) && ((B) > (D)))
+#define ROW_AND_COL_IN_ROW_AT_OR_AFTER(A, B, C, D)                     \
+    (((A) == (C)) && ((B) >= (D)))
+#define ROW_AND_COL_IN_ROW_BEFORE(A, B, C, D)                          \
+    (((A) == (C)) && ((B) < (D)))
+#define ROW_AND_COL_IN_ROW_AT_OR_BEFORE(A, B, C, D)                    \
+    (((A) == (C)) && ((B) <= (D)))
+
+/* these must be row_col_t */
+#define ROWCOL_IS_AFTER(X, Y)                                          \
+    ROW_AND_COL_IS_AFTER ((X).row, (X).col, (Y).row, (Y).col)
+#define ROWCOL_IS_BEFORE(X, Y)                                         \
+    ROW_AND_COL_IS_BEFORE ((X).row, (X).col, (Y).row, (Y).col)
+#define ROWCOL_IN_ROW_AFTER(X, Y)                                      \
+    ROW_AND_COL_IN_ROW_AFTER ((X).row, (X).col, (Y).row, (Y).col)
+#define ROWCOL_IN_ROW_BEFORE(X, Y)                                     \
+    ROW_AND_COL_IN_ROW_BEFORE ((X).row, (X).col, (Y).row, (Y).col)
+#define ROWCOL_IN_ROW_AT_OR_AFTER(X, Y)                                \
+    ROW_AND_COL_IN_ROW_AT_OR_AFTER ((X).row, (X).col, (Y).row, (Y).col)
+#define ROWCOL_IN_ROW_AT_OR_BEFORE(X, Y)                               \
+    ROW_AND_COL_IN_ROW_AT_OR_BEFORE ((X).row, (X).col, (Y).row, (Y).col)
+
+/*
+ * CLEAR_CHARS: clear <num> chars starting from pixel position <x,y>
+ */
+#define CLEAR_CHARS(x, y, num)                                         \
+    if (mapped)                                                        \
+        XClearArea (dpy, vt, x, y,                                     \
+                    (unsigned int)Width2Pixel (num),                   \
+                    (unsigned int)Height2Pixel (1), False)
+
+/* ------------------------------------------------------------------------- *
+ *                        SCREEN `COMMON' ROUTINES                           *
+ * ------------------------------------------------------------------------- */
+
+/* Fill part/all of a line with blanks. */
+void
+rxvt_term::scr_blank_line (line_t &l, unsigned int col, unsigned int width, rend_t efs) const NOTHROW
+{
+  if (!l.valid ())
+    {
+      l.alloc ();
+      col = 0;
+      width = ncol;
+    }
+
+  l.touch ();
+
+  efs &= ~RS_baseattrMask; // remove italic etc. fontstyles
+  efs = SET_FONT (efs, FONTSET (efs)->find_font (' '));
+
+  text_t *et = l.t + col;
+  rend_t *er = l.r + col;
+
+  while (width--)
+    {
+      *et++ = ' ';
+      *er++ = efs;
+    }
+}
+
+/* ------------------------------------------------------------------------- */
+/* Fill a full line with blanks - make sure it is allocated first */
+void
+rxvt_term::scr_blank_screen_mem (line_t &l, rend_t efs) const NOTHROW
+{
+  scr_blank_line (l, 0, ncol, efs);
+
+  l.l = 0;
+  l.f = 0;
+}
+
+// nuke a single wide character at the given column
+void
+rxvt_term::scr_kill_char (line_t &l, int col) const NOTHROW
+{
+  // find begin
+  while (col > 0 && l.t[col] == NOCHAR)
+    col--;
+
+  rend_t rend = l.r[col] & ~RS_baseattrMask;
+  rend = SET_FONT (rend, FONTSET (rend)->find_font (' '));
+
+  l.touch ();
+
+  // found start, nuke
+  do {
+    l.t[col] = ' ';
+    l.r[col] = rend;
+    col++;
+  } while (col < ncol && l.t[col] == NOCHAR);
+}
+
+// set the rendition of a single wide character beginning at the given column
+void
+rxvt_term::scr_set_char_rend (line_t &l, int col, rend_t rend)
+{
+  do {
+    l.r[col] = rend;
+    col++;
+  } while (col < ncol && l.t[col] == NOCHAR);
+}
+
+/* ------------------------------------------------------------------------- *
+ *                          SCREEN INITIALISATION                            *
+ * ------------------------------------------------------------------------- */
+
+void
+rxvt_term::scr_alloc () NOTHROW
+{
+  int tsize = sizeof (text_t) * ncol;
+  int rsize = sizeof (rend_t) * ncol;
+
+  // we assume that rend_t size is a sufficient alignment
+  // factor for text_t and line_t values, and we only
+  // need to adjust tsize.
+  tsize = (tsize + sizeof (rend_t) - 1);
+  tsize -= tsize % sizeof (rend_t);
+
+  int all_rows = total_rows + nrow + nrow;
+
+  chunk_size = (sizeof (line_t) + rsize + tsize) * all_rows;
+  chunk = chunk_alloc (chunk_size, 0);
+
+  char *base = (char *)chunk + sizeof (line_t) * all_rows;
+
+  for (int row = 0; row < all_rows; ++row)
+    {
+      line_t &l = ((line_t *)chunk) [row];
+
+      l.t = (text_t *)base; base += tsize;
+      l.r = (rend_t *)base; base += rsize;
+      l.l = -1;
+      l.f = 0;
+    }
+
+  drawn_buf = (line_t *)chunk;
+  swap_buf  = drawn_buf + nrow;
+  row_buf   = swap_buf  + nrow;
+}
+
+void
+rxvt_term::copy_line (line_t &dst, line_t &src)
+{
+  scr_blank_screen_mem (dst, DEFAULT_RSTYLE);
+  dst.l = min (src.l, ncol);
+  memcpy (dst.t, src.t, sizeof (text_t) * dst.l);
+  memcpy (dst.r, src.r, sizeof (rend_t) * dst.l);
+  dst.f = src.f;
+}
+
+void ecb_cold
+rxvt_term::scr_reset ()
+{
+#if ENABLE_OVERLAY
+  scr_overlay_off ();
+#endif
+
+  view_start = 0;
+  num_scr = 0;
+
+  if (ncol == 0)
+    ncol = 80;
+
+  if (nrow == 0)
+    nrow = 24;
+
+  if (ncol == prev_ncol && nrow == prev_nrow)
+    return;
+
+  // we need at least two lines for wrapping to work correctly
+  while (nrow + saveLines < 2)
+    {
+      //TODO//FIXME
+      saveLines++;
+      prev_nrow--;
+      top_row--;
+    }
+
+  want_refresh = 1;
+
+  int prev_total_rows = prev_nrow + saveLines;
+  total_rows = nrow + saveLines;
+
+  screen.tscroll = 0;
+  screen.bscroll = nrow - 1;
+
+  void *prev_chunk = chunk;
+  size_t prev_chunk_size = chunk_size;
+  line_t *prev_drawn_buf = drawn_buf;
+  line_t *prev_swap_buf  = swap_buf;
+  line_t *prev_row_buf   = row_buf;
+
+  scr_alloc ();
+
+  if (!prev_row_buf)
+    {
+      top_row    = 0;
+      term_start = 0;
+
+      memset (charsets, 'B', sizeof (charsets));
+      rstyle = DEFAULT_RSTYLE;
+      screen.flags = Screen_DefaultFlags;
+      screen.cur.row = screen.cur.col = 0;
+      screen.charset = 0;
+      current_screen = PRIMARY;
+      scr_cursor (SAVE);
+
+#if NSCREENS
+      swap.flags = Screen_DefaultFlags;
+      swap.cur.row = swap.cur.col = 0;
+      swap.charset = 0;
+      current_screen = SECONDARY;
+      scr_cursor (SAVE);
+      current_screen = PRIMARY;
+#endif
+
+      selection.text = NULL;
+      selection.len = 0;
+      selection.op = SELECTION_CLEAR;
+      selection.screen = PRIMARY;
+      selection.clicks = 0;
+      selection.clip_text = NULL;
+      selection.clip_len = 0;
+    }
+  else
+    {
+      /*
+       * add or delete rows as appropriate
+       */
+
+      int common_col = min (prev_ncol, ncol);
+
+      for (int row = min (nrow, prev_nrow); row--; )
+        {
+          scr_blank_screen_mem (drawn_buf [row], DEFAULT_RSTYLE);
+          memcpy (drawn_buf [row].t, prev_drawn_buf [row].t, sizeof (text_t) * common_col);
+          memcpy (drawn_buf [row].r, prev_drawn_buf [row].r, sizeof (rend_t) * common_col);
+
+          copy_line (swap_buf [row], prev_swap_buf [row]);
+        }
+
+      int p    = MOD (term_start + prev_nrow, prev_total_rows);  // previous row
+      int pend = MOD (term_start + top_row  , prev_total_rows);
+      int q    = total_rows; // rewrapped row
+
+      if (top_row)
+        {
+          // Re-wrap lines. This is rather ugly, possibly because I am too dumb
+          // to come up with a lean and mean algorithm.
+          // TODO: maybe optimise when width didn't change
+
+          row_col_t ocur = screen.cur;
+          ocur.row = MOD (term_start + ocur.row, prev_total_rows);
+
+          do
+            {
+              p = MOD (p - 1, prev_total_rows);
+              assert (prev_row_buf [MOD (p, prev_total_rows)].t);
+              int plines = 1;
+              int llen = prev_row_buf [MOD (p, prev_total_rows)].l;
+
+              while (p != pend && prev_row_buf [MOD (p - 1, prev_total_rows)].is_longer ())
+                {
+                  p = MOD (p - 1, prev_total_rows);
+
+                  plines++;
+                  llen += prev_ncol;
+                }
+
+              int qlines = max (0, (llen - 1) / ncol) + 1;
+
+              // drop partial lines completely
+              if (q < qlines)
+                break;
+
+              q -= qlines;
+
+              int lofs = 0;
+              line_t *qline;
+
+              // re-assemble the full line by destination lines
+              for (int qrow = q; qlines--; qrow++)
+                {
+                  qline = row_buf + qrow;
+                  qline->alloc (); // redundant with next line
+                  qline->l = ncol;
+                  qline->is_longer (1);
+
+                  int qcol = 0;
+
+                  // see below for cursor adjustment rationale
+                  if (p == ocur.row)
+                    screen.cur.row = q - (total_rows - nrow);
+
+                  // fill a single destination line
+                  while (lofs < llen && qcol < ncol)
+                    {
+                      int prow = lofs / prev_ncol;
+                      int pcol = lofs % prev_ncol;
+
+                      prow = MOD (p + prow, prev_total_rows);
+
+                      // we only adjust the cursor _row_ and put it into
+                      // the topmost line of "long line" it was in, as
+                      // this seems to upset applications/shells/readline
+                      // least.
+                      if (prow == ocur.row)
+                        screen.cur.row = q - (total_rows - nrow);
+
+                      line_t &pline = prev_row_buf [prow];
+
+                      int len = min (min (prev_ncol - pcol, ncol - qcol), llen - lofs);
+
+                      memcpy (qline->t + qcol, pline.t + pcol, len * sizeof (text_t));
+                      memcpy (qline->r + qcol, pline.r + pcol, len * sizeof (rend_t));
+
+                      lofs += len;
+                      qcol += len;
+                    }
+                }
+
+              qline->l = llen ? MOD (llen - 1, ncol) + 1 : 0;
+              qline->is_longer (0);
+              scr_blank_line (*qline, qline->l, ncol - qline->l, DEFAULT_RSTYLE);
+            }
+          while (p != pend && q > 0);
+
+          term_start = total_rows - nrow;
+          top_row = q - term_start;
+
+          // make sure all terminal lines exist
+          while (top_row > 0)
+            scr_blank_screen_mem (ROW (--top_row), DEFAULT_RSTYLE);
+        }
+      else
+        {
+          // if no scrollback exists (yet), wing, instead of wrap
+
+          for (int row = min (nrow, prev_nrow); row--; )
+            {
+              line_t &src = prev_row_buf [MOD (term_start + row, prev_total_rows)];
+              line_t &dst = row_buf [row];
+
+              copy_line (dst, src);
+            }
+
+          for (int row = prev_nrow; row < nrow; row++)
+            scr_blank_screen_mem (row_buf [row], DEFAULT_RSTYLE);
+
+          term_start = 0;
+        }
+
+      clamp_it (screen.cur.row, 0, nrow - 1);
+      clamp_it (screen.cur.col, 0, ncol - 1);
+    }
+
+  for (int row = nrow; row--; )
+    {
+      if (!ROW       (row).valid ()) scr_blank_screen_mem (ROW       (row), DEFAULT_RSTYLE);
+      if (!swap_buf  [row].valid ()) scr_blank_screen_mem (swap_buf  [row], DEFAULT_RSTYLE);
+      if (!drawn_buf [row].valid ()) scr_blank_screen_mem (drawn_buf [row], DEFAULT_RSTYLE);
+    }
+
+  chunk_free (prev_chunk, prev_chunk_size);
+
+  free (tabs);
+  tabs = (char *)rxvt_malloc (ncol);
+
+  for (int col = ncol; col--; )
+    tabs [col] = col % TABSIZE == 0;
+
+  CLEAR_ALL_SELECTION ();
+
+  prev_nrow = nrow;
+  prev_ncol = ncol;
+
+  tt_winch ();
+
+  HOOK_INVOKE ((this, HOOK_RESET, DT_END));
+}
+
+void ecb_cold
+rxvt_term::scr_release () NOTHROW
+{
+  chunk_free (chunk, chunk_size);
+  chunk = 0;
+  row_buf = 0;
+
+  free (tabs);
+  tabs = 0;
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Hard/Soft reset
+ */
+void ecb_cold
+rxvt_term::scr_poweron ()
+{
+  scr_release ();
+
+  prev_nrow = prev_ncol = 0;
+  rvideo_mode = false;
+  scr_soft_reset ();
+  scr_reset ();
+
+  scr_clear (true);
+  scr_refresh ();
+}
+
+void ecb_cold
+rxvt_term::scr_soft_reset () NOTHROW
+{
+  /* only affects modes, nothing drastic such as clearing the screen */
+#if ENABLE_OVERLAY
+  scr_overlay_off ();
+#endif
+
+  if (current_screen != PRIMARY)
+    scr_swap_screen ();
+
+  scr_scroll_region (0, MAX_ROWS - 1);
+  scr_rendition (0, ~RS_None);
+  scr_insert_mode (0);
+}
+
+/* ------------------------------------------------------------------------- *
+ *                         PROCESS SCREEN COMMANDS                           *
+ * ------------------------------------------------------------------------- */
+/*
+ * Save and Restore cursor
+ * XTERM_SEQ: Save cursor   : ESC 7
+ * XTERM_SEQ: Restore cursor: ESC 8
+ */
+void
+rxvt_term::scr_cursor (cursor_mode mode) NOTHROW
+{
+  screen_t *s;
+
+#if NSCREENS && !defined(NO_SECONDARY_SCREEN_CURSOR)
+  if (current_screen == SECONDARY)
+    s = &swap;
+  else
+#endif
+    s = &screen;
+
+  switch (mode)
+    {
+      case SAVE:
+        s->s_cur.row = screen.cur.row;
+        s->s_cur.col = screen.cur.col;
+        s->s_rstyle = rstyle;
+        s->s_charset = screen.charset;
+        s->s_charset_char = charsets[screen.charset];
+        break;
+
+      case RESTORE:
+        want_refresh = 1;
+        screen.cur.row = s->s_cur.row;
+        screen.cur.col = s->s_cur.col;
+        screen.flags &= ~Screen_WrapNext;
+        rstyle = s->s_rstyle;
+        screen.charset = s->s_charset;
+        charsets[screen.charset] = s->s_charset_char;
+        set_font_style ();
+        break;
+    }
+
+  /* boundary check in case screen size changed between SAVE and RESTORE */
+  min_it (s->cur.row, nrow - 1);
+  min_it (s->cur.col, ncol - 1);
+  assert (s->cur.row >= 0);
+  assert (s->cur.col >= 0);
+}
+
+void
+rxvt_term::scr_swap_screen () NOTHROW
+{
+  if (!option (Opt_secondaryScreen))
+    return;
+
+  for (int i = prev_nrow; i--; )
+    ::swap (ROW(i), swap_buf [i]);
+
+  ::swap (screen.cur, swap.cur);
+
+  screen.cur.row = clamp (screen.cur.row, 0, prev_nrow - 1);
+  screen.cur.col = clamp (screen.cur.col, 0, prev_ncol - 1);
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Swap between primary and secondary screens
+ * XTERM_SEQ: Primary screen  : ESC [ ? 4 7 h
+ * XTERM_SEQ: Secondary screen: ESC [ ? 4 7 l
+ */
+void
+rxvt_term::scr_change_screen (int scrn)
+{
+  if (scrn == current_screen)
+    return;
+
+  want_refresh = 1;
+  view_start = 0;
+
+  /* check for boundary cross */
+  row_col_t pos;
+  pos.row = pos.col = 0;
+  if (ROWCOL_IS_BEFORE (selection.beg, pos)
+      && ROWCOL_IS_AFTER (selection.end, pos))
+    CLEAR_SELECTION ();
+
+  current_screen = scrn;
+
+#if NSCREENS
+  if (option (Opt_secondaryScreen))
+    {
+      num_scr = 0;
+
+      scr_swap_screen ();
+
+      ::swap (screen.charset, swap.charset);
+      ::swap (screen.flags,   swap.flags);
+      screen.flags |= Screen_VisibleCursor;
+      swap.flags   |= Screen_VisibleCursor;
+    }
+  else
+#endif
+    if (option (Opt_secondaryScroll))
+      scr_scroll_text (0, prev_nrow - 1, prev_nrow);
+}
+
+// clear WrapNext indicator, solidifying position on next line
+void
+rxvt_term::scr_do_wrap () NOTHROW
+{
+  if (!(screen.flags & Screen_WrapNext))
+    return;
+
+  screen.flags &= ~Screen_WrapNext;
+
+  screen.cur.col = 0;
+
+  if (screen.cur.row == screen.bscroll)
+    scr_scroll_text (screen.tscroll, screen.bscroll, 1);
+  else if (screen.cur.row < nrow - 1)
+    screen.cur.row++;
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Change the colour for following text
+ */
+void
+rxvt_term::scr_color (unsigned int color, int fgbg) NOTHROW
+{
+  if (!IN_RANGE_INC (color, minCOLOR, maxTermCOLOR24))
+    color = fgbg;
+
+  if (fgbg == Color_fg)
+    rstyle = SET_FGCOLOR (rstyle, color);
+  else
+    rstyle = SET_BGCOLOR (rstyle, color);
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Change the rendition style for following text
+ */
+void
+rxvt_term::scr_rendition (int set, int style) NOTHROW
+{
+  if (set)
+    rstyle |= style;
+  else if (style == ~RS_None)
+    rstyle = DEFAULT_RSTYLE;
+  else
+    rstyle &= ~style;
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Scroll text between <row1> and <row2> inclusive, by <count> lines
+ * count positive ==> scroll up
+ * count negative ==> scroll down
+ */
+int ecb_hot
+rxvt_term::scr_scroll_text (int row1, int row2, int count) NOTHROW
+{
+  if (count == 0 || (row1 > row2))
+    return 0;
+
+  want_refresh = 1;
+  num_scr += count;
+
+  if (count > 0
+      && row1 == 0
+      && (current_screen == PRIMARY || option (Opt_secondaryScroll)))
+    {
+      min_it (count, total_rows - (nrow - (row2 + 1)));
+
+      top_row = max (top_row - count, -saveLines);
+
+      // sever bottommost line
+      {
+        line_t &l = ROW(row2);
+        l.is_longer (0);
+        l.touch ();
+      }
+
+      // scroll everything up 'count' lines
+      term_start = (term_start + count) % total_rows;
+
+      // now copy lines below the scroll region bottom to the
+      // bottom of the screen again, so they look as if they
+      // hadn't moved.
+      for (int i = nrow; --i > row2; )
+        {
+          line_t &l1 = ROW(i - count);
+          line_t &l2 = ROW(i);
+
+          ::swap (l1, l2);
+          l2.touch ();
+        }
+
+      // erase newly scrolled-in lines
+      for (int i = count; i--; )
+        {
+          line_t &l = ROW(row2 - i);
+
+          // optimise if already cleared, can be significant on slow machines
+          // could be rolled into scr_blank_screen_mem
+          if (l.r && l.l < ncol - 1 && !((l.r[l.l + 1] ^ rstyle) & (RS_fgMask | RS_bgMask)))
+            {
+              scr_blank_line (l, 0, l.l, rstyle);
+              l.l = 0;
+              l.f = 0;
+            }
+          else
+            scr_blank_screen_mem (l, rstyle);
+        }
+
+      // move and/or clear selection, if any
+      if (selection.op && current_screen == selection.screen
+          && selection.beg.row <= row2)
+        {
+          selection.beg.row  -= count;
+          selection.end.row  -= count;
+          selection.mark.row -= count;
+
+          selection_check (0);
+        }
+
+      // finally move the view window, if desired
+      if (option (Opt_scrollWithBuffer)
+          && view_start != 0
+          && view_start != -saveLines)
+        scr_page (count);
+
+      if (SHOULD_INVOKE (HOOK_SCROLL_BACK))
+        HOOK_INVOKE ((this, HOOK_SCROLL_BACK, DT_INT, count, DT_INT, top_row, DT_END));
+    }
+  else
+    {
+      if (selection.op && current_screen == selection.screen)
+        {
+          if ((selection.beg.row < row1 && selection.end.row > row1)
+              || (selection.beg.row < row2 && selection.end.row > row2)
+              || (selection.beg.row - count < row1 && selection.beg.row >= row1)
+              || (selection.beg.row - count > row2 && selection.beg.row <= row2)
+              || (selection.end.row - count < row1 && selection.end.row >= row1)
+              || (selection.end.row - count > row2 && selection.end.row <= row2))
+            {
+              CLEAR_ALL_SELECTION ();
+              selection.op = SELECTION_CLEAR;
+            }
+          else if (selection.end.row >= row1 && selection.end.row <= row2)
+            {
+              /* move selected region too */
+              selection.beg.row  -= count;
+              selection.end.row  -= count;
+              selection.mark.row -= count;
+
+              selection_check (0);
+            }
+        }
+
+      // use a simple and robust scrolling algorithm, this
+      // part of scr_scroll_text is not time-critical.
+
+      // sever line above scroll region
+      if (row1)
+        {
+          line_t &l = ROW(row1 - 1);
+          l.is_longer (0);
+          l.touch ();
+        }
+
+      int rows = row2 - row1 + 1;
+
+      min_it (count, rows);
+
+      line_t *temp_buf = rxvt_temp_buf<line_t> (rows);
+
+      for (int row = 0; row < rows; row++)
+        {
+          temp_buf [row] = ROW(row1 + (row + count + rows) % rows);
+
+          if (!IN_RANGE_EXC (row + count, 0, rows))
+            scr_blank_screen_mem (temp_buf [row], rstyle);
+        }
+
+      for (int row = 0; row < rows; row++)
+        ROW(row1 + row) = temp_buf [row];
+
+      // sever bottommost line
+      {
+        line_t &l = ROW(row2);
+        l.is_longer (0);
+        l.touch ();
+      }
+    }
+
+  return count;
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Add text given in <str> of length <len> to screen struct
+ */
+void ecb_hot
+rxvt_term::scr_add_lines (const wchar_t *str, int len, int minlines) NOTHROW
+{
+  if (len <= 0)               /* sanity */
+    return;
+
+  bool checksel;
+  unicode_t c;
+  int ncol = this->ncol;
+  const wchar_t *strend = str + len;
+
+  want_refresh = 1;
+  ZERO_SCROLLBACK ();
+
+  if (minlines > 0)
+    {
+      minlines += screen.cur.row - screen.bscroll;
+      min_it (minlines, screen.cur.row - top_row);
+
+      if (minlines > 0
+          && screen.tscroll == 0
+          && screen.bscroll == nrow - 1)
+        {
+          /* _at least_ this many lines need to be scrolled */
+          scr_scroll_text (screen.tscroll, screen.bscroll, minlines);
+          screen.cur.row -= minlines;
+        }
+    }
+
+  assert (screen.cur.col < ncol);
+  assert (screen.cur.row < nrow
+          && screen.cur.row >= top_row);
+  int row = screen.cur.row;
+
+  checksel = selection.op && current_screen == selection.screen ? 1 : 0;
+
+  line_t *line = &ROW(row);
+
+  while (str < strend)
+    {
+      c = (unicode_t)*str++; // convert to rxvt-unicodes representation
+
+      if (ecb_unlikely (c < 0x20))
+        if (c == C0_LF)
+          {
+            max_it (line->l, screen.cur.col);
+
+            screen.flags &= ~Screen_WrapNext;
+
+            if (screen.cur.row == screen.bscroll)
+              scr_scroll_text (screen.tscroll, screen.bscroll, 1);
+            else if (screen.cur.row < (nrow - 1))
+              row = ++screen.cur.row;
+
+            line = &ROW(row);  /* _must_ refresh */
+            continue;
+          }
+        else if (c == C0_CR)
+          {
+            max_it (line->l, screen.cur.col);
+
+            screen.flags &= ~Screen_WrapNext;
+            screen.cur.col = 0;
+            continue;
+          }
+        else if (c == C0_HT)
+          {
+            scr_tab (1, true);
+            continue;
+          }
+
+      if (ecb_unlikely (
+            checksel            /* see if we're writing within selection */
+            && !ROWCOL_IS_BEFORE (screen.cur, selection.beg)
+            && ROWCOL_IS_BEFORE (screen.cur, selection.end)
+         ))
+        {
+          checksel = 0;
+          /*
+           * If we wrote anywhere in the selected area, kill the selection
+           * XXX: should we kill the mark too?  Possibly, but maybe that
+           *      should be a similar check.
+           */
+          CLEAR_SELECTION ();
+        }
+
+      if (ecb_unlikely (screen.flags & Screen_WrapNext))
+        {
+          scr_do_wrap ();
+
+          line->l = ncol;
+          line->is_longer (1);
+
+          row = screen.cur.row;
+          line = &ROW(row);   /* _must_ refresh */
+        }
+
+      // some utf-8 decoders "decode" surrogate characters: let's fix this.
+      if (ecb_unlikely (IN_RANGE_INC (c, 0xd800, 0xdfff)))
+        c = 0xfffd;
+
+      // rely on wcwidth to tell us the character width, do wcwidth before
+      // further replacements, as wcwidth might return -1 for the line
+      // drawing characters below as they might be invalid in the current
+      // locale.
+      int width = WCWIDTH (c);
+
+      if (ecb_unlikely (charsets [screen.charset] == '0')) // DEC SPECIAL
+        {
+          // vt100 special graphics and line drawing
+          // 5f-7e standard vt100
+          // 40-5e rxvt extension for extra curses acs chars
+          static uint16_t vt100_0[62] = { // 41 .. 7e
+                    0x2191, 0x2193, 0x2192, 0x2190, 0x2588, 0x259a, 0x2603, // 41-47 hi mr. snowman!
+                 0,      0,      0,      0,      0,      0,      0,      0, // 48-4f
+                 0,      0,      0,      0,      0,      0,      0,      0, // 50-57
+                 0,      0,      0,      0,      0,      0,      0, 0x0020, // 58-5f
+            0x25c6, 0x2592, 0x2409, 0x240c, 0x240d, 0x240a, 0x00b0, 0x00b1, // 60-67
+            0x2424, 0x240b, 0x2518, 0x2510, 0x250c, 0x2514, 0x253c, 0x23ba, // 68-6f
+            0x23bb, 0x2500, 0x23bc, 0x23bd, 0x251c, 0x2524, 0x2534, 0x252c, // 70-77
+            0x2502, 0x2264, 0x2265, 0x03c0, 0x2260, 0x00a3, 0x00b7,         // 78-7e
+          };
+
+          if (c >= 0x41 && c <= 0x7e && vt100_0[c - 0x41])
+            {
+              c = vt100_0[c - 0x41];
+              width = 1; // vt100 line drawing characters are always single-width
+            }
+        }
+
+      if (ecb_unlikely (screen.flags & Screen_Insert))
+        scr_insdel_chars (width, INSERT);
+
+      if (width != 0)
+        {
+#if !UNICODE_3
+          // trim characters we can't store directly :(
+          if (c >= 0x10000)
+# if ENABLE_COMBINING
+            c = rxvt_composite.compose (c); // map to lower 16 bits
+# else
+            c = 0xfffd;
+# endif
+#endif
+
+          rend_t rend = SET_FONT (rstyle, FONTSET (rstyle)->find_font (c));
+
+          // if the character doesn't fit into the remaining columns...
+          if (ecb_unlikely (screen.cur.col > ncol - width && ncol >= width))
+            {
+              if (screen.flags & Screen_Autowrap)
+                {
+                  // ... artificially enlargen the previous one
+                  c = NOCHAR;
+                  // and try the same character next loop iteration
+                  --str;
+                }
+              else
+                screen.cur.col = ncol - width;
+            }
+
+          // nuke the character at this position, if required
+          // due to wonderful coincidences everywhere else in this loop
+          // we never have to check for overwriting a wide char itself,
+          // only its tail.
+          if (ecb_unlikely (line->t[screen.cur.col] == NOCHAR))
+            scr_kill_char (*line, screen.cur.col);
+
+          line->touch ();
+
+          do
+            {
+              line->t[screen.cur.col] = c;
+              line->r[screen.cur.col] = rend;
+
+              if (ecb_likely (screen.cur.col < ncol - 1))
+                screen.cur.col++;
+              else
+                {
+                  line->l = ncol;
+                  if (screen.flags & Screen_Autowrap)
+                    screen.flags |= Screen_WrapNext;
+
+                  goto end_of_line;
+                }
+
+              c = NOCHAR;
+            }
+          while (ecb_unlikely (--width > 0));
+
+          // pad with spaces when overwriting wide character with smaller one
+          for (int c = screen.cur.col; ecb_unlikely (c < ncol && line->t[c] == NOCHAR); c++)
+            {
+              line->t[c] = ' ';
+              line->r[c] = rend;
+            }
+
+end_of_line:
+          ;
+        }
+#if ENABLE_COMBINING
+      else // width == 0
+        {
+          if (c != 0xfeff) // ignore BOM
+            {
+              // handle combining characters
+              // we just tag the accent on the previous on-screen character.
+              // this is arguably not correct, but also arguably not wrong.
+              // we don't handle double-width characters nicely yet.
+              line_t *linep;
+              text_t *tp;
+              rend_t *rp;
+
+              if (screen.cur.col > 0)
+                {
+                  linep = line;
+                  tp = line->t + screen.cur.col - 1;
+                  rp = line->r + screen.cur.col - 1;
+                }
+              else if (screen.cur.row > 0
+                       && ROW(screen.cur.row - 1).is_longer ())
+                {
+                  linep = &ROW(screen.cur.row - 1);
+                  tp = linep->t + ncol - 1;
+                  rp = linep->r + ncol - 1;
+                }
+              else
+                continue;
+
+              linep->touch ();
+
+              while (*tp == NOCHAR && tp > linep->t)
+                tp--, rp--;
+
+              // first try to find a precomposed character
+              unicode_t n = rxvt_compose (*tp, c);
+              if (n == NOCHAR)
+                n = rxvt_composite.compose (*tp, c);
+
+              *tp = n;
+              *rp = SET_FONT (*rp, FONTSET (*rp)->find_font (*tp));
+            }
+        }
+#endif
+    }
+
+  max_it (line->l, screen.cur.col);
+
+  assert (screen.cur.row >= 0);
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Process Backspace.  Move back the cursor back a position, wrap if have to
+ * XTERM_SEQ: CTRL-H
+ */
+void
+rxvt_term::scr_backspace () NOTHROW
+{
+  if (screen.cur.col == 0)
+    {
+      if (screen.cur.row > 0)
+        {
+#ifdef TERMCAP_HAS_BW
+          screen.cur.col = ncol - 1;
+          --screen.cur.row;
+
+          want_refresh = 1;
+#endif
+        }
+    }
+  else if (screen.flags & Screen_WrapNext)
+    screen.flags &= ~Screen_WrapNext;
+  else
+    scr_gotorc (0, -1, RELATIVE);
+}
+
+/* ------------------------------------------------------------------------- */
+/*
+ * Process Horizontal Tab
+ * count: +ve = forward; -ve = backwards
+ * XTERM_SEQ: CTRL-I
+ */
+void
+rxvt_term::scr_tab (int count, bool ht) NOTHROW
+{
+  int i, x;
+
+  want_refresh = 1;
+  i = x = screen.cur.col;
+
+  if (count == 0)
+    return;
+  else if (count > 0)
+    {
+      line_t &l = ROW(screen.cur.row);
+      rend_t base_rend = l.r[i];
+      ht &= l.t[i] == ' ';
+
+      for (; ++i < ncol; )
+        if (tabs[i])
+          {
+            x = i;
+
+            if (!--count)
+              break;
+          }
+        else
+          ht &= l.t[i] == ' '
+                && RS_SAME (l.r[i], base_rend);
+
+      if (count)
+        x = ncol - 1;
+
+      // store horizontal tab commands as characters inside the text
+      // buffer so they can be selected and pasted.
+      if (ht && option (Opt_pastableTabs))
+        {
+          base_rend = SET_FONT (base_rend, 0);
+