*** empty log message ***

[gnu-emacs] / src / w32term.c

diff --git a/src/w32term.c b/src/w32term.c
index 2c6559c89328d7d1477fd62784e0d66a62f07685..0422257f2d6a547e009dfc79fb6ee72271551d12 100644 (file)
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -1,12 +1,13 @@
 /* Implementation of GUI terminal on the Microsoft W32 API.
-   Copyright (C) 1989, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
-                 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1989, 1993, 1994, 1995, 1996, 1997, 1998,
+                 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+                 2006, 2007 Free Software Foundation, Inc.
 
 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
-the Free Software Foundation; either version 2, or (at your option)
+the Free Software Foundation; either version 3, or (at your option)
 any later version.
 
 GNU Emacs is distributed in the hope that it will be useful,
@@ -3473,31 +3474,51 @@ w32_set_scroll_bar_thumb (bar, portion, position, whole)
      int portion, position, whole;
 {
   Window w = SCROLL_BAR_W32_WINDOW (bar);
-  double range = VERTICAL_SCROLL_BAR_TOP_RANGE (f, XINT (bar->height));
+  /* We use the whole scroll-bar height in the calculations below, to
+     avoid strange effects like scrolling backwards when just clicking
+     on the handle (without moving it).  */
+  double range = VERTICAL_SCROLL_BAR_TOP_RANGE (f, XINT (bar->height))
+                 + VERTICAL_SCROLL_BAR_MIN_HANDLE;
   int sb_page, sb_pos;
   BOOL draggingp = !NILP (bar->dragging) ? TRUE : FALSE;
   SCROLLINFO si;
 
-  if (whole)
+  /* We used to change the nPage setting while dragging the handle,
+     but that had very strange effects (such as scrolling backwards
+     while dragging downwards).
+
+     Now, we don't change the nPage setting while dragging unless we
+     get near to the end of the buffer, in which case we often have to
+     resize the handle to "go all the way".  */
+
+  if (draggingp)
     {
-#if 0
-      /* This code is not used (the settings are overwritten
-        immediately by the lines below it).
-        Should it be used?  KFS 2007-02-19.  */
+      int near_bottom_p;
+      BLOCK_INPUT;
+      si.cbSize = sizeof (si);
+      si.fMask = SIF_POS | SIF_PAGE;
+      GetScrollInfo(w, SB_CTL, &si);
+      near_bottom_p = si.nPos + si.nPage >= range;
+      UNBLOCK_INPUT;
+      if (!near_bottom_p)
+       return;
+    }
 
+  if (whole)
+    {
       /* Position scroll bar at rock bottom if the bottom of the
          buffer is visible. This avoids shinking the thumb away
          to nothing if it is held at the bottom of the buffer.  */
-      if (position + portion >= whole)
-        {
-          sb_page = range * (whole - position) / whole
-            + VERTICAL_SCROLL_BAR_MIN_HANDLE;
-          sb_pos = range;
-        }
-#endif
-
-      sb_page = portion * range / whole + VERTICAL_SCROLL_BAR_MIN_HANDLE;
-      sb_pos = position * range / whole;
+      if (position + portion >= whole && !draggingp)
+       {
+         sb_page = range * (whole - position) / whole;
+         sb_pos = range;
+       }
+      else
+       {
+         sb_pos = position * range / whole;
+         sb_page = (min (portion, (whole - position)) * range) / whole;
+       }
     }
   else
     {
@@ -3505,19 +3526,16 @@ w32_set_scroll_bar_thumb (bar, portion, position, whole)
       sb_pos = 0;
     }
 
+  sb_page = max (sb_page, VERTICAL_SCROLL_BAR_MIN_HANDLE);
+
   BLOCK_INPUT;
 
   si.cbSize = sizeof (si);
-  /* Only update page size if currently dragging, to reduce
-     flicker effects.  */
-  if (draggingp)
-    si.fMask = SIF_PAGE;
-  else
-    si.fMask = SIF_PAGE | SIF_POS;
+  si.fMask = SIF_PAGE | SIF_POS;
   si.nPage = sb_page;
   si.nPos = sb_pos;
 
-  SetScrollInfo (w, SB_CTL, &si, !draggingp);
+  SetScrollInfo (w, SB_CTL, &si, TRUE);
 
   UNBLOCK_INPUT;
 }
@@ -4318,7 +4336,7 @@ w32_read_socket (sd, expected, hold_quit)
                  /* Window will be selected only when it is not
                     selected now and last mouse movement event was
                     not in it.  Minibuffer window will be selected
-                    iff it is active.  */
+                    only when it is active.  */
                  if (WINDOWP(window)
                      && !EQ (window, last_window)
                      && !EQ (window, selected_window))