Cleanup of window coordinate positioning code.

Now, text area click input events measure Y from the top of the text
area, excluding the header line if any.

* src/dispnew.c (buffer_posn_from_coords): Assume that X counts from
the start of the text area.

* src/keyboard.c (make_lispy_position): For text area clicks, record Y
pixel position relative to the text area, excluding header line.
Also change X and Y to Lisp_Objects, not pointers; don't return
coordinate values via pointers.  Pass ON_TEXT_AREA coordinate to
buffer_posn_from_coords counting from the start of the text area.
(Fposn_at_x_y, make_lispy_event): Callers changed.

* src/w32term.c (w32_read_socket):
* src/msdos.c (dos_rawgetc):
* src/xterm.c (handle_one_xevent): Likewise.

* src/window.c (coordinates_in_window): Change X and Y to ints rather
than pointers; don't return coordinates via pointers.
(struct check_window_data): Change X and Y from pointers to ints.
(window_from_coordinates): Remove args WX and WY; don't return
coordinates via pointers.
(Fcoordinates_in_window_p, window_from_coordinates):
(check_window_containing, Fwindow_at): Callers changed.
(window_relative_x_coord): New function.

* src/window.h (window_from_coordinates, window_relative_x_coord):
Update prototypes.

* src/xdisp.c (remember_mouse_glyph): Change window_from_coordinates
call.  Use window_relative_x_coord.
(note_mouse_highlight): Change window_from_coordinates call.

9 files changed, 244 insertions, 255 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ca673be0074..401a93bbfb3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,35 @@
+2010-11-16  Chong Yidong  <cyd@stupidchicken.com>
+
+        * keyboard.c (make_lispy_position): For text area clicks, record Y
+        pixel position relative to the text area, excluding header line.
+        Also change X and Y to Lisp_Objects, not pointers; don't return
+        coordinate values via pointers.  Pass ON_TEXT_AREA coordinate to
+        buffer_posn_from_coords counting from the start of the text area.
+        (Fposn_at_x_y, make_lispy_event): Callers changed.
+
+        * window.c (coordinates_in_window): Change X and Y to ints rather
+        than pointers; don't return coordinates via pointers.
+        (struct check_window_data): Change X and Y from pointers to ints.
+        (window_from_coordinates): Remove args WX and WY; don't return
+        coordinates via pointers.
+        (Fcoordinates_in_window_p, window_from_coordinates):
+        (check_window_containing, Fwindow_at): Callers changed.
+        (window_relative_x_coord): New function.
+
+        * window.h (window_from_coordinates, window_relative_x_coord):
+        Update prototypes.
+
+        * dispnew.c (buffer_posn_from_coords): Assume that X counts from
+        the start of the text area.
+
+        * xdisp.c (remember_mouse_glyph): Change window_from_coordinates
+        call.  Use window_relative_x_coord.
+        (note_mouse_highlight): Change window_from_coordinates call.
+
+        * w32term.c (w32_read_socket):
+        * msdos.c (dos_rawgetc):
+        * xterm.c (handle_one_xevent): Likewise.
+
 2010-11-16  Dan Nicolaescu  <dann@ics.uci.edu>
 
         * strftime.c (LOCALE_PARAM_DECL): Update for standard C.
diff --git a/src/dispnew.c b/src/dispnew.c
index 116d9972ba5..8835b458fd6 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -5393,7 +5393,7 @@ buffer_posn_from_coords (struct window *w, int *x, int *y, struct display_pos *p
   BYTEPOS (startp) = min (ZV_BYTE, max (BEGV_BYTE, BYTEPOS (startp)));
   start_display (&it, w, startp);
 
-  x0 = *x - WINDOW_LEFT_MARGIN_WIDTH (w);
+  x0 = *x;
 
   /* First, move to the beginning of the row corresponding to *Y.  We
      need to be in that row to get the correct value of base paragraph
diff --git a/src/keyboard.c b/src/keyboard.c
index 017a4981b98..d048404e856 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -5243,24 +5243,22 @@ EMACS_INT double_click_fuzz;
 
 int double_click_count;
 
-/* Return position of a mouse click or wheel event */
+/* X and Y are frame-relative coordinates for a click or wheel event.
+   Return a Lisp-style event list.  */
 
 static Lisp_Object
-make_lispy_position (struct frame *f, Lisp_Object *x, Lisp_Object *y,
+make_lispy_position (struct frame *f, Lisp_Object x, Lisp_Object y,
                      unsigned long time)
 {
-  Lisp_Object window;
   enum window_part part;
   Lisp_Object posn = Qnil;
   Lisp_Object extra_info = Qnil;
-  int wx, wy;
-
-  /* Set `window' to the window under frame pixel coordinates (x,y)  */
-  if (f)
-    window = window_from_coordinates (f, XINT (*x), XINT (*y),
-                                      &part, &wx, &wy, 0);
-  else
-    window = Qnil;
+  /* Coordinate pixel positions to return.  */
+  int xret = 0, yret = 0;
+  /* The window under frame pixel coordinates (x,y)  */
+  Lisp_Object window = f
+    ? window_from_coordinates (f, XINT (x), XINT (y), &part, 0)
+    : Qnil;
 
   if (WINDOWP (window))
     {
@@ -5268,102 +5266,113 @@ make_lispy_position (struct frame *f, Lisp_Object *x, Lisp_Object *y,
       struct window *w = XWINDOW (window);
       Lisp_Object string_info = Qnil;
       EMACS_INT textpos = -1;
-      int rx = -1, ry = -1;
-      int dx = -1, dy = -1;
+      int col = -1, row = -1;
+      int dx  = -1, dy  = -1;
       int width = -1, height = -1;
       Lisp_Object object = Qnil;
 
-      /* Set event coordinates to window-relative coordinates
-         for constructing the Lisp event below.  */
-      XSETINT (*x, wx);
-      XSETINT (*y, wy);
+      /* Pixel coordinates relative to the window corner.  */
+      int wx = XINT (x) - WINDOW_LEFT_EDGE_X (w);
+      int wy = XINT (y) - WINDOW_TOP_EDGE_Y (w);
 
+      /* For text area clicks, return X, Y relative to the corner of
+         this text area.  Note that dX, dY etc are set below, by
+         buffer_posn_from_coords.  */
       if (part == ON_TEXT)
         {
-          wx += WINDOW_LEFT_MARGIN_WIDTH (w);
+          xret = XINT (x) - window_box_left (w, TEXT_AREA);
+          yret = wy - WINDOW_HEADER_LINE_HEIGHT (w);
         }
+      /* For mode line and header line clicks, return X relative to
+         the left window edge; ignore Y.  Use mode_line_string to look
+         for a string on the click position.  */
       else if (part == ON_MODE_LINE || part == ON_HEADER_LINE)
         {
-          /* Mode line or header line.  Look for a string under
-             the mouse that may have a `local-map' property.  */
           Lisp_Object string;
           EMACS_INT charpos;
 
-          posn = part == ON_MODE_LINE ? Qmode_line : Qheader_line;
-          rx = wx, ry = wy;
-          string = mode_line_string (w, part, &rx, &ry, &charpos,
+          posn = (part == ON_MODE_LINE) ? Qmode_line : Qheader_line;
+          /* Note that mode_line_string takes COL, ROW as pixels and
+             converts them to characters.  */
+          col = wx;
+          row = wy;
+          string = mode_line_string (w, part, &col, &row, &charpos,
                                      &object, &dx, &dy, &width, &height);
           if (STRINGP (string))
             string_info = Fcons (string, make_number (charpos));
-          if (w == XWINDOW (selected_window)
-              && current_buffer == XBUFFER (w->buffer))
-            textpos = PT;
-          else
-            textpos = XMARKER (w->pointm)->charpos;
-        }
-      else if (part == ON_VERTICAL_BORDER)
-        {
-          posn = Qvertical_line;
-          wx = -1;
-          dx = 0;
-          width = 1;
+          textpos = (w == XWINDOW (selected_window)
+                     && current_buffer == XBUFFER (w->buffer))
+            ? PT : XMARKER (w->pointm)->charpos;
+
+          xret = wx;
         }
+      /* For fringes and margins, Y is relative to the area's (and the
+         window's) top edge, while X is meaningless.  */
       else if (part == ON_LEFT_MARGIN || part == ON_RIGHT_MARGIN)
         {
           Lisp_Object string;
           EMACS_INT charpos;
 
           posn = (part == ON_LEFT_MARGIN) ? Qleft_margin : Qright_margin;
-          rx = wx, ry = wy;
-          string = marginal_area_string (w, part, &rx, &ry, &charpos,
+          col = wx;
+          row = wy;
+          string = marginal_area_string (w, part, &col, &row, &charpos,
                                          &object, &dx, &dy, &width, &height);
           if (STRINGP (string))
             string_info = Fcons (string, make_number (charpos));
-          if (part == ON_LEFT_MARGIN)
-            wx = 0;
-          else
-            wx = window_box_right_offset (w, TEXT_AREA) - 1;
+          yret = wy - WINDOW_HEADER_LINE_HEIGHT (w);
         }
       else if (part == ON_LEFT_FRINGE)
         {
           posn = Qleft_fringe;
-          rx = 0;
-          dx = wx;
-          wx = (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
-                ? 0
-                : window_box_width (w, LEFT_MARGIN_AREA));
-          dx -= wx;
+          col = 0;
+          dx = wx
+            - (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
+               ? 0 : window_box_width (w, LEFT_MARGIN_AREA));
+          dy = yret = wy - WINDOW_HEADER_LINE_HEIGHT (w);
         }
       else if (part == ON_RIGHT_FRINGE)
         {
           posn = Qright_fringe;
-          rx = 0;
-          dx = wx;
-          wx = (window_box_width (w, LEFT_MARGIN_AREA)
-                + window_box_width (w, TEXT_AREA)
-                + (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
-                   ? window_box_width (w, RIGHT_MARGIN_AREA)
-                   : 0));
-          dx -= wx;
+          col = 0;
+          dx = wx
+            - window_box_width (w, LEFT_MARGIN_AREA)
+            - window_box_width (w, TEXT_AREA)
+            - (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
+               ? window_box_width (w, RIGHT_MARGIN_AREA)
+               : 0);
+          dy = yret = wy - WINDOW_HEADER_LINE_HEIGHT (w);
         }
-      else
+      else if (part == ON_VERTICAL_BORDER)
         {
-          /* Note: We have no special posn for part == ON_SCROLL_BAR.  */
-          wx = max (WINDOW_LEFT_MARGIN_WIDTH (w), wx);
+          posn = Qvertical_line;
+          width = 1;
+          dx = 0;
+          dy = yret = wy;
         }
+      /* Nothing special for part == ON_SCROLL_BAR.  */
 
+      /* For clicks in the text area, fringes, or margins, call
+         buffer_posn_from_coords to extract TEXTPOS, the buffer
+         position nearest to the click.  */
       if (textpos < 0)
         {
           Lisp_Object string2, object2 = Qnil;
           struct display_pos p;
           int dx2, dy2;
           int width2, height2;
-          string2 = buffer_posn_from_coords (w, &wx, &wy, &p,
+          /* The pixel X coordinate passed to buffer_posn_from_coords
+             is the X coordinate relative to the text area for
+             text-area clicks, zero otherwise.  */
+          int x2 = (part == ON_TEXT) ? xret : 0;
+          int y2 = wy;
+
+          string2 = buffer_posn_from_coords (w, &x2, &y2, &p,
                                              &object2, &dx2, &dy2,
                                              &width2, &height2);
           textpos = CHARPOS (p.pos);
-          if (rx < 0) rx = wx;
-          if (ry < 0) ry = wy;
+          if (col < 0) col = x2;
+          if (row < 0) row = y2;
           if (dx < 0) dx = dx2;
           if (dy < 0) dy = dy2;
           if (width < 0) width = width2;
@@ -5394,34 +5403,27 @@ make_lispy_position (struct frame *f, Lisp_Object *x, Lisp_Object *y,
 #endif
 
       /* Object info */
-      extra_info = Fcons (object,
-                          Fcons (Fcons (make_number (dx),
-                                        make_number (dy)),
-                                 Fcons (Fcons (make_number (width),
-                                               make_number (height)),
-                                        Qnil)));
+      extra_info
+        = list3 (object,
+                 Fcons (make_number (dx), make_number (dy)),
+                 Fcons (make_number (width), make_number (height)));
 
       /* String info */
       extra_info = Fcons (string_info,
                           Fcons (make_number (textpos),
-                                 Fcons (Fcons (make_number (rx),
-                                               make_number (ry)),
+                                 Fcons (Fcons (make_number (col),
+                                               make_number (row)),
                                         extra_info)));
     }
   else if (f != 0)
-    {
-      XSETFRAME (window, f);
-    }
+    XSETFRAME (window, f);
   else
-    {
-      window = Qnil;
-      XSETFASTINT (*x, 0);
-      XSETFASTINT (*y, 0);
-    }
+    window = Qnil;
 
   return Fcons (window,
                 Fcons (posn,
-                       Fcons (Fcons (*x, *y),
+                       Fcons (Fcons (make_number (xret),
+                                     make_number (yret)),
                               Fcons (make_number (time),
                                      extra_info))));
 }
@@ -5610,14 +5612,6 @@ make_lispy_event (struct input_event *event)
                 int hpos;
                 int i;
 
-#if 0
-                /* Activate the menu bar on the down event.  If the
-                   up event comes in before the menu code can deal with it,
-                   just ignore it.  */
-                if (! (event->modifiers & down_modifier))
-                  return Qnil;
-#endif
-
                 /* Find the menu bar item under `column'.  */
                 item = Qnil;
                 items = FRAME_MENU_BAR_ITEMS (f);
@@ -5649,7 +5643,7 @@ make_lispy_event (struct input_event *event)
               }
 #endif /* not USE_X_TOOLKIT && not USE_GTK && not HAVE_NS */
 
-            position = make_lispy_position (f, &event->x, &event->y,
+            position = make_lispy_position (f, event->x, event->y,
                                             event->timestamp);
           }
 #ifndef USE_TOOLKIT_SCROLL_BARS
@@ -5749,23 +5743,21 @@ make_lispy_event (struct input_event *event)
               return Qnil;
 
             event->modifiers &= ~up_modifier;
-#if 0 /* Formerly we treated an up with no down as a click event.  */
-            if (!CONSP (start_pos))
-              event->modifiers |= click_modifier;
-            else
-#endif
+
               {
-                Lisp_Object down;
+                Lisp_Object new_down, down;
                 EMACS_INT xdiff = double_click_fuzz, ydiff = double_click_fuzz;
 
                 /* The third element of every position
                    should be the (x,y) pair.  */
                 down = Fcar (Fcdr (Fcdr (start_pos)));
+                new_down = Fcar (Fcdr (Fcdr (position)));
+
                 if (CONSP (down)
                     && INTEGERP (XCAR (down)) && INTEGERP (XCDR (down)))
                   {
-                    xdiff = XINT (event->x) - XINT (XCAR (down));
-                    ydiff = XINT (event->y) - XINT (XCDR (down));
+                    xdiff = XINT (XCAR (new_down)) - XINT (XCAR (down));
+                    ydiff = XINT (XCDR (new_down)) - XINT (XCDR (down));
                   }
 
                 if (ignore_mouse_drag_p)
@@ -5848,7 +5840,7 @@ make_lispy_event (struct input_event *event)
         if (! FRAME_LIVE_P (f))
           return Qnil;
 
-        position = make_lispy_position (f, &event->x, &event->y,
+        position = make_lispy_position (f, event->x, event->y,
                                         event->timestamp);
 
         /* Set double or triple modifiers to indicate the wheel speed.  */
@@ -5868,10 +5860,8 @@ make_lispy_event (struct input_event *event)
           else
             abort ();
 
-          if (FRAME_WINDOW_P (f))
-            fuzz = double_click_fuzz;
-          else
-            fuzz = double_click_fuzz / 8;
+          fuzz = FRAME_WINDOW_P (f)
+            ? double_click_fuzz : double_click_fuzz / 8;
 
           if (event->modifiers & up_modifier)
             {
@@ -6009,7 +5999,7 @@ make_lispy_event (struct input_event *event)
         if (! FRAME_LIVE_P (f))
           return Qnil;
 
-        position = make_lispy_position (f, &event->x, &event->y,
+        position = make_lispy_position (f, event->x, event->y,
                                         event->timestamp);
 
         head = modify_event_symbol (0, event->modifiers,
@@ -6092,8 +6082,8 @@ make_lispy_event (struct input_event *event)
         start_pos_ptr = &AREF (button_down_location, button);
         start_pos = *start_pos_ptr;
 
-        position = make_lispy_position (f, &event->x, &event->y,
-                                            event->timestamp);
+        position = make_lispy_position (f, event->x, event->y,
+                                        event->timestamp);
 
         if (event->modifiers & down_modifier)
           *start_pos_ptr = Fcopy_alist (position);
@@ -6152,25 +6142,19 @@ make_lispy_movement (FRAME_PTR frame, Lisp_Object bar_window, enum scroll_bar_pa
 
       part_sym = *scroll_bar_parts[(int) part];
       return Fcons (Qscroll_bar_movement,
-                    (Fcons (Fcons (bar_window,
-                                   Fcons (Qvertical_scroll_bar,
-                                          Fcons (Fcons (x, y),
-                                                 Fcons (make_number (time),
-                                                        Fcons (part_sym,
-                                                               Qnil))))),
-                            Qnil)));
+                    Fcons (list5 (bar_window,
+                                  Qvertical_scroll_bar,
+                                  Fcons (x, y),
+                                  make_number (time),
+                                  part_sym),
+                           Qnil));
     }
-
   /* Or is it an ordinary mouse movement?  */
   else
     {
       Lisp_Object position;
-
-      position = make_lispy_position (frame, &x, &y, time);
-
-      return Fcons (Qmouse_movement,
-                    Fcons (position,
-                           Qnil));
+      position = make_lispy_position (frame, x, y, time);
+      return list2 (Qmouse_movement, position);
     }
 }
 
@@ -11327,7 +11311,7 @@ The `posn-' functions access elements of such lists.  */)
 
   CHECK_LIVE_FRAME (frame_or_window);
 
-  return make_lispy_position (XFRAME (frame_or_window), &x, &y, 0);
+  return make_lispy_position (XFRAME (frame_or_window), x, y, 0);
 }
 
 DEFUN ("posn-at-point", Fposn_at_point, Sposn_at_point, 0, 2, 0,
diff --git a/src/msdos.c b/src/msdos.c
index 6593714ba1f..964fde0cbf5 100644
--- a/src/msdos.c
+++ b/src/msdos.c
@@ -2698,7 +2698,7 @@ dos_rawgetc (void)
               mouse_window = window_from_coordinates (SELECTED_FRAME(),
                                                       mouse_last_x,
                                                       mouse_last_y,
-                                                      0, 0, 0, 0);
+                                                      0, 0);
               /* A window will be selected only when it is not
                  selected now, and the last mouse movement event was
                  not in it.  A minibuffer window will be selected iff
diff --git a/src/w32term.c b/src/w32term.c
index 33b60c568c0..7145efbc604 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -4317,7 +4317,7 @@ w32_read_socket (struct terminal *terminal, int expected,
                   int x = LOWORD (msg.msg.lParam);
                   int y = HIWORD (msg.msg.lParam);
 
-                  window = window_from_coordinates (f, x, y, 0, 0, 0, 0);
+                  window = window_from_coordinates (f, x, y, 0, 0);
 
                   /* Window will be selected only when it is not
                      selected now and last mouse movement event was
@@ -4396,7 +4396,7 @@ w32_read_socket (struct terminal *terminal, int expected,
                     int x = XFASTINT (inev.x);
                     int y = XFASTINT (inev.y);
 
-                    window = window_from_coordinates (f, x, y, 0, 0, 0, 1);
+                    window = window_from_coordinates (f, x, y, 0, 1);
 
                     if (EQ (window, f->tool_bar_window))
                       {
diff --git a/src/window.c b/src/window.c
index 086cd858c2e..a2a0c793111 100644
--- a/src/window.c
+++ b/src/window.c
@@ -755,32 +755,26 @@ display margins, fringes, header line, and/or mode line.  */)
                              - WINDOW_MODE_LINE_HEIGHT (w) + add_y));
 }
 
-/* Test if the character at column *X, row *Y is within window W.
+/* Test if the character at column X, row Y is within window W.
    If it is not, return ON_NOTHING;
-   if it is in the window's text area,
-      set *x and *y to its location relative to the upper left corner
-         of the window, and
-      return ON_TEXT;
+   if it is in the window's text area, return ON_TEXT;
    if it is on the window's modeline, return ON_MODE_LINE;
    if it is on the border between the window and its right sibling,
       return ON_VERTICAL_BORDER.
-   if it is on a scroll bar,
-      return ON_SCROLL_BAR.
+   if it is on a scroll bar, return ON_SCROLL_BAR.
    if it is on the window's top line, return ON_HEADER_LINE;
    if it is in left or right fringe of the window,
-      return ON_LEFT_FRINGE or ON_RIGHT_FRINGE, and convert *X and *Y
-      to window-relative coordinates;
+      return ON_LEFT_FRINGE or ON_RIGHT_FRINGE;
    if it is in the marginal area to the left/right of the window,
-      return ON_LEFT_MARGIN or ON_RIGHT_MARGIN, and convert *X and *Y
-      to window-relative coordinates.
+      return ON_LEFT_MARGIN or ON_RIGHT_MARGIN.
 
    X and Y are frame relative pixel coordinates.  */
 
 static enum window_part
-coordinates_in_window (register struct window *w, register int *x, register int *y)
+coordinates_in_window (register struct window *w, int x, int y)
 {
   struct frame *f = XFRAME (WINDOW_FRAME (w));
-  int left_x, right_x, top_y, bottom_y;
+  int left_x, right_x;
   enum window_part part;
   int ux = FRAME_COLUMN_WIDTH (f);
   int x0 = WINDOW_LEFT_EDGE_X (w);
@@ -789,6 +783,12 @@ coordinates_in_window (register struct window *w, register int *x, register int
      (Between mode lines for instance.  */
   int grabbable_width = ux;
   int lmargin_width, rmargin_width, text_left, text_right;
+  int top_y = WINDOW_TOP_EDGE_Y (w);
+  int bottom_y = WINDOW_BOTTOM_EDGE_Y (w);
+
+  /* Outside any interesting row?  */
+  if (y < top_y || y >= bottom_y)
+    return ON_NOTHING;
 
   /* In what's below, we subtract 1 when computing right_x because we
      want the rightmost pixel, which is given by left_pixel+width-1.  */
@@ -796,21 +796,13 @@ coordinates_in_window (register struct window *w, register int *x, register int
     {
       left_x = 0;
       right_x = WINDOW_TOTAL_WIDTH (w) - 1;
-      top_y = WINDOW_TOP_EDGE_Y (w);
-      bottom_y = WINDOW_BOTTOM_EDGE_Y (w);
     }
   else
     {
       left_x = WINDOW_BOX_LEFT_EDGE_X (w);
       right_x = WINDOW_BOX_RIGHT_EDGE_X (w) - 1;
-      top_y = WINDOW_TOP_EDGE_Y (w);
-      bottom_y = WINDOW_BOTTOM_EDGE_Y (w);
     }
 
-  /* Outside any interesting row?  */
-  if (*y < top_y || *y >= bottom_y)
-    return ON_NOTHING;
-
   /* On the mode line or header line?  If it's near the start of
      the mode or header line of window that's has a horizontal
      sibling, say it's on the vertical line.  That's to be able
@@ -818,7 +810,7 @@ coordinates_in_window (register struct window *w, register int *x, register int
      scroll bars.  */
 
   if (WINDOW_WANTS_MODELINE_P (w)
-      && *y >= bottom_y - CURRENT_MODE_LINE_HEIGHT (w))
+      && y >= bottom_y - CURRENT_MODE_LINE_HEIGHT (w))
     {
       part = ON_MODE_LINE;
 
@@ -827,60 +819,37 @@ coordinates_in_window (register struct window *w, register int *x, register int
          between mode lines of horizontally adjacent mode lines
          as the vertical border.  If scroll bars on the left,
          return the right window.  */
-      if (WINDOW_HAS_VERTICAL_SCROLL_BAR_ON_LEFT (w)
-          || WINDOW_RIGHTMOST_P (w))
-        {
-          if (!WINDOW_LEFTMOST_P (w) && eabs (*x - x0) < grabbable_width)
-            {
-              /* Convert X and Y to window relative coordinates.
-                 Vertical border is at the left edge of window.  */
-              *x = max (0, *x - x0);
-              *y -= top_y;
-              return ON_VERTICAL_BORDER;
-            }
-        }
-      else
-        {
-          /* Make sure we're not at the rightmost position of a
-             mode-/header-line and there's yet another window on
-             the right.  (Bug#1372)  */
-          if ((WINDOW_RIGHTMOST_P (w) || *x < x1)
-              && eabs (*x - x1) < grabbable_width)
-            {
-              /* Convert X and Y to window relative coordinates.
-                 Vertical border is at the right edge of window.  */
-              *x = min (x1, *x) - x0;
-              *y -= top_y;
-              return ON_VERTICAL_BORDER;
-            }
-        }
-
-      if (*x < x0 || *x >= x1)
+      if ((WINDOW_HAS_VERTICAL_SCROLL_BAR_ON_LEFT (w)
+           || WINDOW_RIGHTMOST_P (w))
+          && !WINDOW_LEFTMOST_P (w)
+          && eabs (x - x0) < grabbable_width)
+        return ON_VERTICAL_BORDER;
+
+      /* Make sure we're not at the rightmost position of a
+         mode-/header-line and there's yet another window on the
+         right.  (Bug#1372)  */
+      else if ((WINDOW_RIGHTMOST_P (w) || x < x1)
+               && eabs (x - x1) < grabbable_width)
+        return ON_VERTICAL_BORDER;
+
+      if (x < x0 || x >= x1)
         return ON_NOTHING;
 
-      /* Convert X and Y to window relative coordinates.
-         Mode line starts at left edge of window.  */
-      *x -= x0;
-      *y -= top_y;
       return part;
     }
 
   if (WINDOW_WANTS_HEADER_LINE_P (w)
-      && *y < top_y + CURRENT_HEADER_LINE_HEIGHT (w))
+      && y < top_y + CURRENT_HEADER_LINE_HEIGHT (w))
     {
       part = ON_HEADER_LINE;
       goto header_vertical_border_check;
     }
 
-  if (*x < x0 || *x >= x1)
-    return ON_NOTHING;
+  if (x < x0 || x >= x1) return ON_NOTHING;
 
   /* Outside any interesting column?  */
-  if (*x < left_x || *x > right_x)
-    {
-      *y -= top_y;
-      return ON_SCROLL_BAR;
-    }
+  if (x < left_x || x > right_x)
+    return ON_SCROLL_BAR;
 
   lmargin_width = window_box_width (w, LEFT_MARGIN_AREA);
   rmargin_width = window_box_width (w, RIGHT_MARGIN_AREA);
@@ -893,77 +862,79 @@ coordinates_in_window (register struct window *w, register int *x, register int
       if (!w->pseudo_window_p
           && !WINDOW_HAS_VERTICAL_SCROLL_BAR (w)
           && !WINDOW_RIGHTMOST_P (w)
-          && (eabs (*x - right_x) < grabbable_width))
-        {
-          /* Convert X and Y to window relative coordinates.
-             Vertical border is at the right edge of window.  */
-          *x = min (right_x, *x) - left_x;
-          *y -= top_y;
-          return ON_VERTICAL_BORDER;
-        }
-    }
-  else
-    {
-      /* Need to say "*x > right_x" rather than >=, since on character
-         terminals, the vertical line's x coordinate is right_x.  */
-      if (!w->pseudo_window_p
-          && !WINDOW_RIGHTMOST_P (w)
-          && *x > right_x - ux)
-        {
-          /* On the border on the right side of the window?  Assume that
-             this area begins at RIGHT_X minus a canonical char width.  */
-          *x = min (right_x, *x) - left_x;
-          *y -= top_y;
-          return ON_VERTICAL_BORDER;
-        }
+          && (eabs (x - right_x) < grabbable_width))
+        return ON_VERTICAL_BORDER;
     }
+  /* Need to say "x > right_x" rather than >=, since on character
+     terminals, the vertical line's x coordinate is right_x.  */
+  else if (!w->pseudo_window_p
+           && !WINDOW_RIGHTMOST_P (w)
+           && x > right_x - ux)
+    return ON_VERTICAL_BORDER;
 
-  if (*x < text_left)
+  if (x < text_left)
     {
       if (lmargin_width > 0
           && (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
-              ? (*x >= left_x + WINDOW_LEFT_FRINGE_WIDTH (w))
-              : (*x < left_x + lmargin_width)))
-        {
-          *x -= left_x;
-          if (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w))
-            *x -= WINDOW_LEFT_FRINGE_WIDTH (w);
-          *y -= top_y;
-          return ON_LEFT_MARGIN;
-        }
+              ? (x >= left_x + WINDOW_LEFT_FRINGE_WIDTH (w))
+              : (x < left_x + lmargin_width)))
+        return ON_LEFT_MARGIN;
 
-      /* Convert X and Y to window-relative pixel coordinates.  */
-      *x -= left_x;
-      *y -= top_y;
       return ON_LEFT_FRINGE;
     }
 
-  if (*x >= text_right)
+  if (x >= text_right)
     {
       if (rmargin_width > 0
           && (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
-              ? (*x < right_x - WINDOW_RIGHT_FRINGE_WIDTH (w))
-              : (*x >= right_x - rmargin_width)))
-        {
-          *x -= right_x - rmargin_width;
-          if (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w))
-            *x += WINDOW_RIGHT_FRINGE_WIDTH (w);
-          *y -= top_y;
-          return ON_RIGHT_MARGIN;
-        }
+              ? (x < right_x - WINDOW_RIGHT_FRINGE_WIDTH (w))
+              : (x >= right_x - rmargin_width)))
+        return ON_RIGHT_MARGIN;
 
-      /* Convert X and Y to window-relative pixel coordinates.  */
-      *x -= left_x + WINDOW_LEFT_FRINGE_WIDTH (w);
-      *y -= top_y;
       return ON_RIGHT_FRINGE;
     }
 
   /* Everything special ruled out - must be on text area */
-  *x -= text_left;
-  *y -= top_y;
   return ON_TEXT;
 }
 
+/* Take X is the frame-relative pixel x-coordinate, and return the
+   x-coordinate relative to part PART of window W. */
+int
+window_relative_x_coord (struct window *w, enum window_part part, int x)
+{
+  int left_x = (w->pseudo_window_p) ? 0 : WINDOW_BOX_LEFT_EDGE_X (w);
+
+  switch (part)
+    {
+    case ON_TEXT:
+      return x - window_box_left (w, TEXT_AREA);
+
+    case ON_LEFT_FRINGE:
+      return x - left_x;
+
+    case ON_RIGHT_FRINGE:
+      return x - left_x - WINDOW_LEFT_FRINGE_WIDTH (w);
+
+    case ON_LEFT_MARGIN:
+      return (x - left_x
+              - ((WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w))
+                 ? WINDOW_LEFT_FRINGE_WIDTH (w) : 0));
+
+    case ON_RIGHT_MARGIN:
+      return (x + 1
+              - ((w->pseudo_window_p)
+                 ? WINDOW_TOTAL_WIDTH (w)
+                 : WINDOW_BOX_RIGHT_EDGE_X (w))
+              + window_box_width (w, RIGHT_MARGIN_AREA)
+              + ((WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w))
+                 ? WINDOW_RIGHT_FRINGE_WIDTH (w) : 0));
+    }
+
+  /* ON_SCROLL_BAR, ON_NOTHING, and ON_VERTICAL_BORDER:  */
+  return 0;
+}
+
 
 DEFUN ("coordinates-in-window-p", Fcoordinates_in_window_p,
        Scoordinates_in_window_p, 2, 2, 0,
@@ -1000,14 +971,16 @@ If they are in the windows's left or right marginal areas, `left-margin'\n\
   x = FRAME_PIXEL_X_FROM_CANON_X (f, lx) + FRAME_INTERNAL_BORDER_WIDTH (f);
   y = FRAME_PIXEL_Y_FROM_CANON_Y (f, ly) + FRAME_INTERNAL_BORDER_WIDTH (f);
 
-  switch (coordinates_in_window (w, &x, &y))
+  switch (coordinates_in_window (w, x, y))
     {
     case ON_NOTHING:
       return Qnil;
 
     case ON_TEXT:
-      /* X and Y are now window relative pixel coordinates.  Convert
-         them to canonical char units before returning them.  */
+      /* Convert X and Y to window relative pixel coordinates, and
+         return the canonical char units.  */
+      x -= window_box_left (w, TEXT_AREA);
+      y -= WINDOW_TOP_EDGE_Y (w);
       return Fcons (FRAME_CANON_X_FROM_PIXEL_X (f, x),
                     FRAME_CANON_Y_FROM_PIXEL_Y (f, y));
 
@@ -1054,7 +1027,7 @@ If they are in the windows's left or right marginal areas, `left-margin'\n\
 struct check_window_data
 {
   Lisp_Object *window;
-  int *x, *y;
+  int x, y;
   enum window_part *part;
 };
 
@@ -1081,8 +1054,7 @@ check_window_containing (struct window *w, void *user_data)
    return it as a Lisp_Object.
 
    If X, Y is on one of the window's special `window_part' elements,
-   set *PART to the id of that element, and return X and Y converted
-   to window relative coordinates in WX and WY.
+   set *PART to the id of that element.
 
    If there is no window under X, Y return nil and leave *PART
    unmodified.  TOOL_BAR_P non-zero means detect tool-bar windows.
@@ -1097,7 +1069,8 @@ check_window_containing (struct window *w, void *user_data)
    case.  */
 
 Lisp_Object
-window_from_coordinates (struct frame *f, int x, int y, enum window_part *part, int *wx, int *wy, int tool_bar_p)
+window_from_coordinates (struct frame *f, int x, int y,
+                         enum window_part *part, int tool_bar_p)
 {
   Lisp_Object window;
   struct check_window_data cw;
@@ -1107,7 +1080,7 @@ window_from_coordinates (struct frame *f, int x, int y, enum window_part *part,
     part = &dummy;
 
   window = Qnil;
-  cw.window = &window, cw.x = &x, cw.y = &y; cw.part = part;
+  cw.window = &window, cw.x = x, cw.y = y; cw.part = part;
   foreach_window (f, check_window_containing, &cw);
 
   /* If not found above, see if it's in the tool bar window, if a tool
@@ -1116,16 +1089,13 @@ window_from_coordinates (struct frame *f, int x, int y, enum window_part *part,
       && tool_bar_p
       && WINDOWP (f->tool_bar_window)
       && WINDOW_TOTAL_LINES (XWINDOW (f->tool_bar_window)) > 0
-      && (coordinates_in_window (XWINDOW (f->tool_bar_window), &x, &y)
+      && (coordinates_in_window (XWINDOW (f->tool_bar_window), x, y)
           != ON_NOTHING))
     {
       *part = ON_TEXT;
       window = f->tool_bar_window;
     }
 
-  if (wx) *wx = x;
-  if (wy) *wy = y;
-
   return window;
 }
 
@@ -1152,7 +1122,7 @@ column 0.  */)
                                    + FRAME_INTERNAL_BORDER_WIDTH (f)),
                                   (FRAME_PIXEL_Y_FROM_CANON_Y (f, y)
                                    + FRAME_INTERNAL_BORDER_WIDTH (f)),
-                                  0, 0, 0, 0);
+                                  0, 0);
 }
 
 DEFUN ("window-point", Fwindow_point, Swindow_point, 0, 1, 0,
diff --git a/src/window.h b/src/window.h
index e9529487b14..c1148836d79 100644
--- a/src/window.h
+++ b/src/window.h
@@ -788,8 +788,7 @@ EXFUN (Fset_window_point, 2);
 extern Lisp_Object make_window (void);
 extern void delete_window (Lisp_Object);
 extern Lisp_Object window_from_coordinates (struct frame *, int, int,
-                                            enum window_part *,
-                                            int *, int*, int);
+                                            enum window_part *, int);
 EXFUN (Fwindow_dedicated_p, 1);
 extern int window_height (Lisp_Object);
 extern int window_width (Lisp_Object);
@@ -804,6 +803,7 @@ extern void foreach_window (struct frame *,
                             void *);
 extern void grow_mini_window (struct window *, int);
 extern void shrink_mini_window (struct window *);
+extern int window_relative_x_coord (struct window *, enum window_part, int);
 
 void run_window_configuration_change_hook (struct frame *f);
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 21c89088383..d3ebc1a4a8a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2218,7 +2218,7 @@ remember_mouse_glyph (struct frame *f, int gx, int gy, NativeRectangle *rect)
      frame pixel coordinates X/Y on frame F.  */
 
   if (!f->glyphs_initialized_p
-      || (window = window_from_coordinates (f, gx, gy, &part, &x, &y, 0),
+      || (window = window_from_coordinates (f, gx, gy, &part, 0),
           NILP (window)))
     {
       width = FRAME_SMALLEST_CHAR_WIDTH (f);
@@ -2230,6 +2230,9 @@ remember_mouse_glyph (struct frame *f, int gx, int gy, NativeRectangle *rect)
   width = WINDOW_FRAME_COLUMN_WIDTH (w);
   height = WINDOW_FRAME_LINE_HEIGHT (w);
 
+  x = window_relative_x_coord (w, part, gx);
+  y = gy - WINDOW_TOP_EDGE_Y (w);
+
   r = MATRIX_FIRST_TEXT_ROW (w->current_matrix);
   end_row = MATRIX_BOTTOM_TEXT_ROW (w->current_matrix, w);
 
@@ -25383,7 +25386,7 @@ note_mouse_highlight (struct frame *f, int x, int y)
     }
 
   /* Which window is that in?  */
-  window = window_from_coordinates (f, x, y, &part, 0, 0, 1);
+  window = window_from_coordinates (f, x, y, &part, 1);
 
   /* If we were displaying active text in another window, clear that.
      Also clear if we move out of text area in same window.  */
diff --git a/src/xterm.c b/src/xterm.c
index 331ff9ab4a9..eaa19523970 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -6658,7 +6658,7 @@ handle_one_xevent (struct x_display_info *dpyinfo, XEvent *eventp, int *finish,
 
                 window = window_from_coordinates (f,
                                                   event.xmotion.x, event.xmotion.y,
-                                                  0, 0, 0, 0);
+                                                  0, 0);
 
                 /* Window will be selected only when it is not selected now and
                    last mouse movement event was not in it.  Minibuffer window
@@ -6797,7 +6797,7 @@ handle_one_xevent (struct x_display_info *dpyinfo, XEvent *eventp, int *finish,
                 int x = event.xbutton.x;
                 int y = event.xbutton.y;
 
-                window = window_from_coordinates (f, x, y, 0, 0, 0, 1);
+                window = window_from_coordinates (f, x, y, 0, 1);
                 tool_bar_p = EQ (window, f->tool_bar_window);
 
                 if (tool_bar_p && event.xbutton.button < 4)