Adding upstream version 4.9.1.upstream/4.9.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 918 insertions, 0 deletions

diff --git a/canvas.c b/canvas.c
new file mode 100644
index 0000000..919e94d
--- /dev/null
+++ b/canvas.c
@@ -0,0 +1,918 @@
+/* Copyright (c) 2008, 2009
+ *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ *      Micah Cowan (micah@cowan.name)
+ *      Sadrul Habib Chowdhury (sadrul@users.sourceforge.net)
+ * Copyright (c) 1993-2002, 2003, 2005, 2006, 2007
+ *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ * Copyright (c) 1987 Oliver Laumann
+ *
+ * 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, 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 (see the file COPYING); if not, see
+ * https://www.gnu.org/licenses/, or contact Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
+ *
+ ****************************************************************
+ */
+
+#include "config.h"
+#include "screen.h"
+#include "extern.h"
+#include "canvas.h"
+#include "list_generic.h"
+
+extern struct display *display;
+extern struct win *fore, *windows;
+extern struct layer *flayer;
+extern int captionalways;
+extern struct LayFuncs BlankLf;
+extern int focusminwidth, focusminheight;
+
+static void
+CanvasInitBlank(cv)
+struct canvas *cv;
+{
+  cv->c_blank.l_cvlist = cv;
+  cv->c_blank.l_width = cv->c_xe - cv->c_xs + 1;
+  cv->c_blank.l_height = cv->c_ye - cv->c_ys + 1;
+  cv->c_blank.l_x = cv->c_blank.l_y = 0;
+  cv->c_blank.l_layfn = &BlankLf;
+  cv->c_blank.l_data = 0;
+  cv->c_blank.l_next = 0;
+  cv->c_blank.l_bottom = &cv->c_blank;
+  cv->c_blank.l_blocking = 0;
+  cv->c_layer = &cv->c_blank;
+}
+
+static void
+FreePerp(pcv)
+struct canvas *pcv;
+{
+  struct canvas *cv;
+
+  if (!pcv->c_slperp)
+    return;
+  cv = pcv->c_slperp;
+  cv->c_slprev = pcv->c_slprev;
+  if (cv->c_slprev)
+    cv->c_slprev->c_slnext = cv;
+  cv->c_slback = pcv->c_slback;
+  if (cv->c_slback && cv->c_slback->c_slperp == pcv)
+    cv->c_slback->c_slperp = cv;
+  cv->c_slorient = pcv->c_slorient;
+  cv->c_slweight = pcv->c_slweight;
+  while (cv->c_slnext)
+    {
+      cv = cv->c_slnext;
+      cv->c_slorient = pcv->c_slorient;
+      cv->c_slback = pcv->c_slback;
+      cv->c_slweight = pcv->c_slweight;
+    }
+  cv->c_slnext = pcv->c_slnext;
+  if (cv->c_slnext)
+    cv->c_slnext->c_slprev = cv;
+  LayerCleanupMemory(&pcv->c_blank);
+  free(pcv);
+}
+
+void
+FreeCanvas(cv)
+struct canvas *cv;
+{
+  struct viewport *vp, *nvp;
+  struct canvas **cvp;
+  struct win *p;
+
+  if (cv->c_slprev)
+    cv->c_slprev->c_slnext = cv->c_slnext;
+  if (cv->c_slnext)
+    cv->c_slnext->c_slprev = cv->c_slprev;
+  if (cv->c_slback && cv->c_slback->c_slperp == cv)
+    cv->c_slback->c_slperp = cv->c_slnext ? cv->c_slnext : cv->c_slprev;
+  if (cv->c_slperp)
+    {
+      while (cv->c_slperp)
+	FreeCanvas(cv->c_slperp);
+      LayerCleanupMemory(&cv->c_blank);
+      free(cv);
+      return;
+    }
+
+  if (display)
+    {
+      if (D_forecv == cv)
+	D_forecv = 0;
+      /* remove from canvas chain as SetCanvasWindow might call
+       * some layer function */
+      for (cvp = &D_cvlist; *cvp ; cvp = &(*cvp)->c_next)
+	if (*cvp == cv)
+	  {
+	    *cvp = cv->c_next;
+	    break;
+	  }
+    }
+  p = cv->c_layer ? Layer2Window(cv->c_layer) : 0;
+  SetCanvasWindow(cv, 0);
+  if (p)
+    WindowChanged(p, 'u');
+  if (flayer == cv->c_layer)
+    flayer = 0;
+  for (vp = cv->c_vplist; vp; vp = nvp)
+    {
+      vp->v_canvas = 0;
+      nvp = vp->v_next;
+      vp->v_next = 0;
+      free(vp);
+    }
+  evdeq(&cv->c_captev);
+  LayerCleanupMemory(&cv->c_blank);
+  free(cv);
+}
+
+int
+CountCanvas(cv)
+struct canvas *cv;
+{
+  int num = 0;
+  for (; cv; cv = cv->c_slnext)
+    {
+      if (cv->c_slperp)
+	{
+	  struct canvas *cvp;
+	  int nump = 1, n;
+          for (cvp = cv->c_slperp; cvp; cvp = cvp->c_slnext)
+	    if (cvp->c_slperp)
+	      {
+		n = CountCanvas(cvp->c_slperp);
+		if (n > nump)
+		  nump = n;
+	      }
+	  num += nump;
+	}
+      else
+	num++;
+    }
+  return num;
+}
+
+int
+CountCanvasPerp(cv)
+struct canvas *cv;
+{
+  struct canvas *cvp;
+  int num = 1, n;
+  for (cvp = cv->c_slperp; cvp; cvp = cvp->c_slnext)
+    if (cvp->c_slperp)
+      {
+	n = CountCanvas(cvp->c_slperp);
+	if (n > num)
+	  num = n;
+      }
+  return num;
+}
+
+struct canvas *
+FindCanvas(x, y)
+int x, y;
+{
+  struct canvas *cv, *mcv = 0;
+  int m, mm = 0;
+
+  for (cv = D_cvlist; cv; cv = cv->c_next)
+    {
+      /* ye + 1 because of caption line */
+      if (x >= cv->c_xs && x <= cv->c_xe && y >= cv->c_ys && y <= cv->c_ye + 1)
+	return cv;
+      if (cv == D_forecv)
+	continue;
+      m = 0;
+      if (x >= D_forecv->c_xs && x <= D_forecv->c_xe)
+	{
+	  if (x < cv->c_xs || x > cv->c_xe)
+	    continue;
+          if (y < D_forecv->c_ys && y < cv->c_ys)
+	    continue;
+          if (y > D_forecv->c_ye + 1 && y > cv->c_ye + 1)
+	    continue;
+	  if (y < cv->c_ys)
+	    m = cv->c_ys - y;
+	  if (y > cv->c_ye + 1)
+	    m = y - (cv->c_ye + 1);
+	}
+      if (y >= D_forecv->c_ys && y <= D_forecv->c_ye + 1)
+	{
+	  if (y < cv->c_ys || y > cv->c_ye + 1)
+	    continue;
+          if (x < D_forecv->c_xs && x < cv->c_xs)
+	    continue;
+          if (x > D_forecv->c_xe && x > cv->c_xe)
+	    continue;
+	  if (x < cv->c_xs)
+	    m = cv->c_xs - x;
+	  if (x > cv->c_xe)
+	    m = x - cv->c_xe;
+	}
+      if (m && (!mm || m < mm))
+	{
+	  mcv = cv;
+	  mm = m;
+	}
+    }
+  return mcv ? mcv : D_forecv;
+}
+
+void
+SetCanvasWindow(cv, wi)
+struct canvas *cv;
+struct win *wi;
+{
+  struct win *p = 0, **pp;
+  struct layer *l;
+  struct canvas *cvp, **cvpp;
+
+  l = cv->c_layer;
+  display = cv->c_display;
+
+  if (l)
+    {
+      /* remove old layer */
+      for (cvpp = &l->l_cvlist; (cvp = *cvpp); cvpp = &cvp->c_lnext)
+	if (cvp == cv)
+	  break;
+      ASSERT(cvp);
+      *cvpp = cvp->c_lnext;
+
+      p = Layer2Window(l);
+      l = cv->c_layer;
+      cv->c_layer = 0;
+
+      if (p && cv == D_forecv)
+	{
+#ifdef MULTIUSER
+	  ReleaseAutoWritelock(display, p);
+#endif
+	  if (p->w_silence)
+	    {
+	      SetTimeout(&p->w_silenceev, p->w_silencewait * 1000);
+	      evenq(&p->w_silenceev);
+	    }
+	  D_other = fore;
+	  D_fore = 0;
+	}
+      if (l->l_cvlist == 0 && (p == 0 || l != p->w_savelayer))
+	KillLayerChain(l);
+    }
+
+  /* find right layer to display on canvas */
+  if (wi && wi->w_type != W_TYPE_GROUP)
+    {
+      l = &wi->w_layer;
+      if (wi->w_savelayer && (wi->w_blocked || wi->w_savelayer->l_cvlist == 0))
+	l = wi->w_savelayer;
+    }
+  else
+    {
+      l = &cv->c_blank;
+      if (wi)
+	l->l_data = (char *)wi;
+      else
+	l->l_data = 0;
+    }
+
+  /* add our canvas to the layer's canvaslist */
+  ASSERT(l->l_cvlist != cv);
+  cv->c_lnext = l->l_cvlist;
+  l->l_cvlist = cv;
+  cv->c_layer = l;
+  cv->c_xoff = cv->c_xs;
+  cv->c_yoff = cv->c_ys;
+  RethinkViewportOffsets(cv);
+
+  if (flayer == 0)
+    flayer = l;
+
+  if (wi && wi->w_type == W_TYPE_GROUP)
+    {
+      /* auto-start windowlist on groups */
+      struct display *d = display;
+      struct layer *oldflayer = flayer;
+      flayer = l;
+      display_windows(0, 0, wi);
+      flayer = oldflayer;
+      display = d;
+    }
+
+  if (wi && D_other == wi)
+    D_other = wi->w_next;	/* Might be 0, but that's OK. */
+  if (cv == D_forecv)
+    {
+      D_fore = wi;
+      fore = D_fore;	/* XXX ? */
+      if (wi)
+	{
+#ifdef MULTIUSER
+	  ObtainAutoWritelock(display, wi);
+#endif
+	  /*
+	   * Place the window at the head of the most-recently-used list
+	   */
+	  if (windows != wi)
+	    {
+	      for (pp = &windows; (p = *pp); pp = &p->w_next)
+		if (p == wi)
+		  break;
+	      ASSERT(p);
+	      *pp = p->w_next;
+	      p->w_next = windows;
+	      windows = p;
+	      WListLinkChanged();
+	    }
+	}
+    }
+}
+
+static void
+cv_winid_fn(ev, data)
+struct event *ev;
+char *data;
+{
+  int ox, oy;
+  struct canvas *cv = (struct canvas *)data;
+
+  display = cv->c_display;
+  if (D_status == STATUS_ON_WIN)
+    {
+      SetTimeout(ev, 1);
+      evenq(ev);
+      return;
+    }
+  ox = D_x;
+  oy = D_y;
+  if (cv->c_ye + 1 < D_height)
+    RefreshLine(cv->c_ye + 1, 0, D_width - 1, 0);
+  if (ox != -1 && oy != -1)
+    GotoPos(ox, oy);
+}
+
+int
+MakeDefaultCanvas()
+{
+  struct canvas *cv;
+ 
+  ASSERT(display);
+  if ((cv = (struct canvas *)calloc(1, sizeof *cv)) == 0)
+    return -1;
+  cv->c_xs      = 0;
+  cv->c_xe      = D_width - 1;
+  cv->c_ys      = (D_has_hstatus == HSTATUS_FIRSTLINE);
+  cv->c_ye      = D_height - 1 - (D_has_hstatus == HSTATUS_LASTLINE) - captionalways;
+  debug2("MakeDefaultCanvas 0,0 %d,%d\n", cv->c_xe, cv->c_ye);
+  cv->c_xoff    = 0;
+  cv->c_yoff    = 0;
+  cv->c_next = 0;
+  cv->c_display = display;
+  cv->c_vplist = 0;
+  cv->c_slnext = 0;
+  cv->c_slprev = 0;
+  cv->c_slperp = 0;
+  cv->c_slweight = 1;
+  cv->c_slback = &D_canvas;
+  D_canvas.c_slperp = cv;
+  D_canvas.c_xs = cv->c_xs;
+  D_canvas.c_xe = cv->c_xe;
+  D_canvas.c_ys = cv->c_ys;
+  D_canvas.c_ye = cv->c_ye;
+  cv->c_slorient = SLICE_UNKN;
+  cv->c_captev.type = EV_TIMEOUT;
+  cv->c_captev.data = (char *)cv;
+  cv->c_captev.handler = cv_winid_fn;
+
+  CanvasInitBlank(cv);
+  cv->c_lnext = 0;
+
+  D_cvlist = cv;
+  RethinkDisplayViewports();
+  D_forecv = cv; 	      /* default input focus */
+  return 0;
+}
+
+static struct canvas **
+CreateCanvasChainRec(cv, cvp)
+struct canvas *cv;
+struct canvas **cvp;
+{
+  for (; cv; cv = cv->c_slnext)
+    {
+      if (cv->c_slperp)
+	cvp = CreateCanvasChainRec(cv->c_slperp, cvp);
+      else
+	{
+	  *cvp = cv;
+	  cvp = &cv->c_next;
+	}
+    }
+  return cvp;
+}
+
+void
+RecreateCanvasChain()
+{
+  struct canvas **cvp;
+  cvp = CreateCanvasChainRec(D_canvas.c_slperp, &D_cvlist);
+  *cvp = 0;
+}
+
+void
+EqualizeCanvas(cv, gflag)
+struct canvas *cv;
+int gflag;
+{
+  struct canvas *cv2;
+  for (; cv; cv = cv->c_slnext)
+    {
+      if (cv->c_slperp && gflag)
+	{
+	  cv->c_slweight = CountCanvasPerp(cv);
+	  for (cv2 = cv->c_slperp; cv2; cv2 = cv2->c_slnext)
+	    if (cv2->c_slperp)
+	      EqualizeCanvas(cv2->c_slperp, gflag);
+	}
+      else
+	cv->c_slweight = 1;
+    }
+}
+
+void
+ResizeCanvas(cv)
+struct canvas *cv;
+{
+  struct canvas *cv2, *cvn, *fcv;
+  int nh, i, maxi, hh, m, w, wsum;
+  int need, got;
+  int xs, ys, xe, ye;
+  int focusmin = 0;
+
+  xs = cv->c_xs;
+  ys = cv->c_ys;
+  xe = cv->c_xe;
+  ye = cv->c_ye;
+  cv = cv->c_slperp;
+  debug2("ResizeCanvas: %d,%d", xs, ys);
+  debug2(" %d,%d\n", xe, ye);
+  if (cv == 0)
+    return;
+  if (cv->c_slorient == SLICE_UNKN)
+    {
+      ASSERT(!cv->c_slnext && !cv->c_slperp);
+      cv->c_xs = xs;
+      cv->c_xe = xe;
+      cv->c_ys = ys;
+      cv->c_ye = ye;
+      cv->c_xoff = cv->c_xs;
+      cv->c_yoff = cv->c_ys;
+      cv->c_blank.l_width = cv->c_xe - cv->c_xs + 1;
+      cv->c_blank.l_height = cv->c_ye - cv->c_ys + 1;
+      return;
+    }
+
+  fcv = 0;
+  if (focusminwidth || focusminheight)
+    {
+      debug("searching for focus canvas\n");
+      cv2 = D_forecv;
+      while (cv2->c_slback)
+        {
+	  if (cv2->c_slback == cv->c_slback)
+	    {
+	      fcv = cv2;
+	      focusmin = cv->c_slorient == SLICE_VERT ? focusminheight : focusminwidth;
+	      if (focusmin > 0)
+		focusmin--;
+	      else if (focusmin < 0)
+		focusmin = cv->c_slorient == SLICE_VERT ? ye - ys + 2 : xe - xs + 2;
+	      debug1("found, focusmin=%d\n", focusmin);
+	    }
+          cv2 = cv2->c_slback;
+        }
+    }
+  if (focusmin)
+    {
+      m = CountCanvas(cv) * 2;
+      nh = cv->c_slorient == SLICE_VERT ? ye - ys + 2 : xe - xs + 2;
+      nh -= m;
+      if (nh < 0)
+	nh = 0;
+      if (focusmin > nh)
+	focusmin = nh;
+      debug1("corrected to %d\n", focusmin);
+    }
+
+  /* pass 1: calculate weight sum */
+  for (cv2 = cv, wsum = 0; cv2; cv2 = cv2->c_slnext)
+    {
+      debug1("  weight %d\n", cv2->c_slweight);
+      wsum += cv2->c_slweight;
+    }
+  debug1("wsum = %d\n", wsum);
+  if (wsum == 0)
+    wsum = 1;
+  w = wsum;
+
+  /* pass 2: calculate need/excess space */
+  nh = cv->c_slorient == SLICE_VERT ? ye - ys + 2 : xe - xs + 2;
+  for (cv2 = cv, need = got = 0; cv2; cv2 = cv2->c_slnext)
+    {
+      m = cv2->c_slperp ? CountCanvasPerp(cv2) * 2 - 1 : 1;
+      if (cv2 == fcv)
+	m += focusmin;
+      hh = cv2->c_slweight ? nh * cv2->c_slweight / w : 0;
+      w -= cv2->c_slweight;
+      nh -= hh;
+      debug2("  should %d min %d\n", hh, m);
+      if (hh <= m + 1)
+        need += m + 1 - hh;
+      else
+        got += hh - m - 1;
+    }
+  debug2("need: %d, got %d\n", need, got);
+  if (need > got)
+    need = got;
+
+  /* pass 3: distribute space */
+  nh = cv->c_slorient == SLICE_VERT ? ye - ys + 2 : xe - xs + 2;
+  i = cv->c_slorient == SLICE_VERT ? ys : xs;
+  maxi = cv->c_slorient == SLICE_VERT ? ye : xe;
+  w = wsum;
+  for (; cv; cv = cvn)
+    {
+      cvn = cv->c_slnext;
+      if (i > maxi)
+	{
+	  if (cv->c_slprev && !cv->c_slback->c_slback && !cv->c_slprev->c_slperp && !cv->c_slprev->c_slprev)
+	    {
+	      cv->c_slprev->c_slorient = SLICE_UNKN;
+	      if (!captionalways)
+		{
+	          cv->c_slback->c_ye++;
+		  cv->c_slprev->c_ye++;
+		}
+	    }
+	  SetCanvasWindow(cv, 0);
+	  FreeCanvas(cv);
+	  continue;
+	}
+      m = cv->c_slperp ? CountCanvasPerp(cv) * 2 - 1 : 1;
+      if (cv == fcv)
+	m += focusmin;
+      hh = cv->c_slweight ? nh * cv->c_slweight / w : 0;
+      w -= cv->c_slweight;
+      nh -= hh;
+      debug2("  should %d min %d\n", hh, m);
+      if (hh <= m + 1)
+	{
+	  hh = m + 1;
+	  debug1(" -> %d\n", hh);
+	}
+      else
+	{
+	  int hx = 1;       //FIXME Division by zero (got) is posible. "hx = 1" is random number here!!!
+    if (got != 0)
+      hx = need * (hh - m - 1) / got;
+    else
+      debug("   got = 0\n");
+
+	  debug3(" -> %d - %d = %d\n", hh, hx, hh - hx);
+	  got -= (hh - m - 1);
+	  hh -= hx;
+	  need -= hx;
+          debug2("   now need=%d got=%d\n", need, got);
+	}
+      ASSERT(hh >= m + 1);
+      /* hh is window size plus pation line */
+      if (i + hh > maxi + 2)
+	{
+	  hh = maxi + 2 - i;
+	  debug1("  not enough space, reducing to %d\n", hh);
+	}
+      if (i + hh == maxi + 1)
+	{
+	  hh++;
+	  debug("  incrementing as no other canvas will fit\n");
+	}
+      if (cv->c_slorient == SLICE_VERT)
+        {
+          cv->c_xs = xs;
+          cv->c_xe = xe;
+          cv->c_ys = i;
+          cv->c_ye = i + hh - 2;
+          cv->c_xoff = xs;
+          cv->c_yoff = i;
+        }
+      else
+        {
+          cv->c_xs = i;
+          cv->c_xe = i + hh - 2;
+          cv->c_ys = ys;
+          cv->c_ye = ye;
+          cv->c_xoff = i;
+          cv->c_yoff = ys;
+        }
+      cv->c_xoff = cv->c_xs;
+      cv->c_yoff = cv->c_ys;
+      cv->c_blank.l_width = cv->c_xe - cv->c_xs + 1;
+      cv->c_blank.l_height = cv->c_ye - cv->c_ys + 1;
+      if (cv->c_slperp)
+	{
+          ResizeCanvas(cv);
+	  if (!cv->c_slperp->c_slnext)
+	    {
+	      debug("deleting perp node\n");
+	      FreePerp(cv->c_slperp);
+	      FreePerp(cv);
+	    }
+	}
+      i += hh;
+    }
+}
+
+static struct canvas *
+AddPerp(cv)
+struct canvas *cv;
+{
+  struct canvas *pcv;
+  debug("Creating new perp node\n");
+
+  if ((pcv = (struct canvas *)calloc(1, sizeof *cv)) == 0)
+    return 0;
+  pcv->c_next = 0;
+  pcv->c_display = cv->c_display;
+  pcv->c_slnext = cv->c_slnext;
+  pcv->c_slprev = cv->c_slprev;
+  pcv->c_slperp = cv;
+  pcv->c_slback = cv->c_slback;
+  if (cv->c_slback && cv->c_slback->c_slperp == cv)
+    cv->c_slback->c_slperp = pcv;
+  pcv->c_slorient = cv->c_slorient;
+  pcv->c_xoff = 0;
+  pcv->c_yoff = 0;
+  pcv->c_xs = cv->c_xs;
+  pcv->c_xe = cv->c_xe;
+  pcv->c_ys = cv->c_ys;
+  pcv->c_ye = cv->c_ye;
+  if (pcv->c_slnext)
+    pcv->c_slnext->c_slprev = pcv;
+  if (pcv->c_slprev)
+    pcv->c_slprev->c_slnext = pcv;
+  pcv->c_slweight = cv->c_slweight;
+  CanvasInitBlank(pcv);
+  cv->c_slweight = 1;
+  cv->c_slnext = 0;
+  cv->c_slprev = 0;
+  cv->c_slperp = 0;
+  cv->c_slback = pcv;
+  cv->c_slorient = SLICE_UNKN;
+  return pcv;
+}
+
+int
+AddCanvas(orient)
+int orient;
+{
+  struct canvas *cv;
+  int xs, xe, ys, ye;
+  int h, num;
+
+  cv = D_forecv;
+  debug2("AddCanvas orient %d, forecv is %d\n", orient, cv->c_slorient);
+
+  if (cv->c_slorient != SLICE_UNKN && cv->c_slorient != orient)
+    if (!AddPerp(cv))
+      return -1;
+
+  cv = D_forecv;
+  xs = cv->c_slback->c_xs;
+  xe = cv->c_slback->c_xe;
+  ys = cv->c_slback->c_ys;
+  ye = cv->c_slback->c_ye;
+  if (!captionalways && cv == D_canvas.c_slperp && !cv->c_slnext)
+    ye--;	/* need space for caption */
+  debug2("Adding Canvas to slice %d,%d ", xs, ys);
+  debug2("%d,%d\n", xe, ye);
+
+  num = CountCanvas(cv->c_slback->c_slperp) + 1;
+  debug1("Num = %d\n", num);
+  if (orient == SLICE_VERT)
+    h = ye - ys + 1;
+  else
+    h = xe - xs + 1;
+
+  h -= 2 * num - 1;
+  if (h < 0)
+    return -1;		/* can't fit in */
+
+  if ((cv = (struct canvas *)calloc(1, sizeof *cv)) == 0)
+    return -1;
+
+  D_forecv->c_slback->c_ye = ye;	/* in case we modified it above */
+  D_forecv->c_slorient = orient;	/* in case it was UNKN */
+  cv->c_slnext = D_forecv->c_slnext;
+  cv->c_slprev = D_forecv;
+  D_forecv->c_slnext = cv;
+  if (cv->c_slnext)
+    cv->c_slnext->c_slprev = cv;
+  cv->c_slorient = orient;
+  cv->c_slback = D_forecv->c_slback;
+
+  cv->c_xs      = xs;
+  cv->c_xe      = xe;
+  cv->c_ys      = ys;
+  cv->c_ye      = ye;
+  cv->c_xoff    = 0;
+  cv->c_yoff    = 0;
+  cv->c_display = display;
+  cv->c_vplist  = 0;
+  cv->c_captev.type = EV_TIMEOUT;
+  cv->c_captev.data = (char *)cv;
+  cv->c_captev.handler = cv_winid_fn;
+
+  CanvasInitBlank(cv);
+  cv->c_lnext = 0;
+
+  cv->c_next    = 0;
+
+  cv = cv->c_slback;
+  EqualizeCanvas(cv->c_slperp, 0);
+  ResizeCanvas(cv);
+  RecreateCanvasChain();
+  RethinkDisplayViewports();
+  ResizeLayersToCanvases();
+  return 0;
+}
+
+void
+RemCanvas()
+{
+  int ye;
+  struct canvas *cv;
+
+  debug("RemCanvas\n");
+  cv = D_forecv;
+  ye = cv->c_slback->c_ye;
+  if (cv->c_slorient == SLICE_UNKN)
+    return;
+  while (cv->c_slprev)
+    cv = cv->c_slprev;
+  if (!cv->c_slnext)
+    return;
+  if (!cv->c_slnext->c_slnext && cv->c_slback->c_slback)
+    {
+      /* two canvases in slice, kill perp node */
+      cv = D_forecv;
+      debug("deleting perp node\n");
+      FreePerp(cv->c_slprev ? cv->c_slprev : cv->c_slnext);
+      FreePerp(cv->c_slback);
+    }
+  /* free canvas */
+  cv = D_forecv;
+  D_forecv = cv->c_slprev;
+  if (!D_forecv)
+    D_forecv = cv->c_slnext;
+  FreeCanvas(cv);
+
+  cv = D_forecv;
+  while (D_forecv->c_slperp)
+    D_forecv = D_forecv->c_slperp;
+
+  /* if only one canvas left, set orient back to unknown */
+  if (!cv->c_slnext && !cv->c_slprev && !cv->c_slback->c_slback && !cv->c_slperp)
+    {
+      cv->c_slorient = SLICE_UNKN;
+      if (!captionalways)
+	cv->c_slback->c_ye = ++ye;	/* caption line no longer needed */
+    }
+  cv = cv->c_slback;
+  EqualizeCanvas(cv->c_slperp, 0);
+  ResizeCanvas(cv);
+
+  D_fore = Layer2Window(D_forecv->c_layer);
+  flayer = D_forecv->c_layer;
+
+  RecreateCanvasChain();
+  RethinkDisplayViewports();
+  ResizeLayersToCanvases();
+}
+
+void
+OneCanvas()
+{
+  struct canvas *cv = D_forecv, *ocv = 0;
+
+  if (cv->c_slprev)
+    {
+      ocv = cv->c_slprev;
+      cv->c_slprev->c_slnext = cv->c_slnext;
+    }
+  if (cv->c_slnext)
+    {
+      ocv = cv->c_slnext;
+      cv->c_slnext->c_slprev = cv->c_slprev;
+    }
+  if (!ocv)
+    return;
+  if (cv->c_slback && cv->c_slback->c_slperp == cv)
+    cv->c_slback->c_slperp = ocv;
+  cv->c_slorient = SLICE_UNKN;
+  while (D_canvas.c_slperp)
+    FreeCanvas(D_canvas.c_slperp);
+  cv = D_forecv;
+  D_canvas.c_slperp = cv;
+  cv->c_slback = &D_canvas;
+  cv->c_slnext = 0;
+  cv->c_slprev = 0;
+  ASSERT(!cv->c_slperp);
+  if (!captionalways)
+    D_canvas.c_ye++;	/* caption line no longer needed */
+  ResizeCanvas(&D_canvas);
+  RecreateCanvasChain();
+  RethinkDisplayViewports();
+  ResizeLayersToCanvases();
+}
+
+void
+DupLayoutCv(cvf, cvt, save)
+struct canvas *cvf, *cvt;
+int save;
+{
+  while(cvf)
+    {
+      cvt->c_slorient = cvf->c_slorient;
+      cvt->c_slweight = cvf->c_slweight;
+      if (cvf == D_forecv)
+        D_forecv = cvt;
+      if (!save)
+	{
+	  cvt->c_display = display;
+	  if (!cvf->c_slperp)
+	    {
+	      cvt->c_captev.type = EV_TIMEOUT;
+	      cvt->c_captev.data = (char *)cvt;
+	      cvt->c_captev.handler = cv_winid_fn;
+	      cvt->c_blank.l_cvlist = 0;
+	      cvt->c_blank.l_layfn = &BlankLf;
+	      cvt->c_blank.l_bottom = &cvt->c_blank;
+	    }
+          cvt->c_layer = cvf->c_layer;
+	}
+      else
+	{
+	  struct win *p = cvf->c_layer ? Layer2Window(cvf->c_layer) : 0;
+          cvt->c_layer = p ? &p->w_layer : 0;
+	}
+      if (cvf->c_slperp)
+	{
+	  cvt->c_slperp = (struct canvas *)calloc(1, sizeof(struct canvas));
+	  cvt->c_slperp->c_slback = cvt;
+	  CanvasInitBlank(cvt->c_slperp);
+	  DupLayoutCv(cvf->c_slperp, cvt->c_slperp, save);
+	}
+      if (cvf->c_slnext)
+	{
+	  cvt->c_slnext = (struct canvas *)calloc(1, sizeof(struct canvas));
+	  cvt->c_slnext->c_slprev = cvt;
+	  cvt->c_slnext->c_slback = cvt->c_slback;
+	  CanvasInitBlank(cvt->c_slnext);
+	}
+      cvf = cvf->c_slnext;
+      cvt = cvt->c_slnext;
+    }
+}
+
+void
+PutWindowCv(cv)
+struct canvas *cv;
+{
+  struct win *p;
+  for (; cv; cv = cv->c_slnext)
+    {
+      if (cv->c_slperp)
+	{
+	  PutWindowCv(cv->c_slperp);
+	  continue;
+	}
+      p = cv->c_layer ? (struct win *)cv->c_layer->l_data : 0;
+      cv->c_layer = 0;
+      SetCanvasWindow(cv, p);
+    }
+}
+