Re: Mode-line customization.

[Masatake YAMATO]

About Mode-line customization, it may be nice to support mouse-face on
mode-line (and header-line).

I've tried to implement mouse-face on mode-line, but it doesn't work perfectly.
I need advices from the display engine experts.

- success:
With the patch, the major mode indicator on mode-line is highlighted 
when the mouse cursor is moved on it. 

- problem:
However, in ruler-mode, current column indicator on header-line is not
highlighted but the character at 0 column on header-line is highlighted
when the mouse cursor is moved on the current column indicator.

Masatake YAMATO
Index: src/xdisp.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/xdisp.c,v
retrieving revision 1.887
diff -u -r1.887 xdisp.c
--- src/xdisp.c 4 May 2004 12:51:45 -0000       1.887
+++ src/xdisp.c 6 May 2004 00:06:20 -0000
@@ -20640,11 +20640,12 @@
    position relative to the start of the mode line.  */
 
 static void
-note_mode_line_or_margin_highlight (w, x, y, area)
-     struct window *w;
+note_mode_line_or_margin_highlight (window, x, y, area)
+     Lisp_Object window;
      int x, y;
      enum window_part area;
 {
+  struct window *w = XWINDOW (window);
   struct frame *f = XFRAME (w->frame);
   Display_Info *dpyinfo = FRAME_X_DISPLAY_INFO (f);
   Cursor cursor = FRAME_X_OUTPUT (f)->nontext_cursor;
@@ -20653,6 +20654,9 @@
   Lisp_Object string, object = Qnil;
   Lisp_Object pos, help;
 
+  Lisp_Object mouse_face;
+  int original_x_pixel = x;
+  
   if (area == ON_MODE_LINE || area == ON_HEADER_LINE)
     string = mode_line_string (w, area, &x, &y, &charpos,
                               &object, &dx, &dy, &width, &height);
@@ -20728,6 +20732,53 @@
          if (!KEYMAPP (map))
            cursor = dpyinfo->vertical_scroll_bar_cursor;
        }
+      
+     /* Change the mouse face according to what is under X/Y.  */
+      mouse_face = Fget_text_property (pos, Qmouse_face, string);
+      if (!NILP (mouse_face) && ((area == ON_MODE_LINE) || (area == 
ON_HEADER_LINE)))
+       {
+         Lisp_Object b, e;
+         struct glyph * glyph;
+         struct glyph_row *row;
+         int ignore;
+
+         if (clear_mouse_face (dpyinfo))
+           cursor = No_Cursor;
+         
+         b = Fprevious_single_property_change(make_number (charpos + 1),
+                                              Qmouse_face, string, Qnil);
+         e = Fnext_single_property_change (pos, Qmouse_face, string, Qnil);
+         if (NILP (b))
+           b = make_number (0);
+         if (NILP (e))
+           e = make_number (SCHARS (string) - 1);
+
+         dpyinfo->mouse_face_beg_col = (x - charpos) + XINT(b);
+         dpyinfo->mouse_face_beg_row = (area == ON_MODE_LINE)? 
+           (w->current_matrix)->nrows - 1: 
+           0;
+         dpyinfo->mouse_face_beg_x   = original_x_pixel - ((charpos  * width) 
+ dx);
+         dpyinfo->mouse_face_beg_y   = 0;
+         
+         dpyinfo->mouse_face_end_col = (x - charpos) + XINT(e) + 1;
+         dpyinfo->mouse_face_end_row = dpyinfo->mouse_face_beg_row;
+         dpyinfo->mouse_face_end_x   = 0;
+         dpyinfo->mouse_face_end_y   = 0;
+         
+         dpyinfo->mouse_face_past_end = 0;
+         dpyinfo->mouse_face_window  = window;
+
+         row = (area == ON_MODE_LINE)? 
+           MATRIX_MODE_LINE_ROW (w->current_matrix):
+           MATRIX_HEADER_LINE_ROW(w->current_matrix);
+         glyph = row->glyphs[TEXT_AREA] + dpyinfo->mouse_face_beg_col;
+         dpyinfo->mouse_face_face_id = face_at_string_position(w, string, 
+                                                               charpos,
+                                                               0, 0, 0, 
&ignore,
+                                                               glyph->face_id, 
1);
+
+         show_mouse_face (dpyinfo, DRAW_MOUSE_FACE);
+       }
     }
 
   define_frame_cursor1 (f, cursor, pointer);
@@ -20806,7 +20857,7 @@
   if (part == ON_MODE_LINE || part == ON_HEADER_LINE
       || part == ON_LEFT_MARGIN || part == ON_RIGHT_MARGIN)
     {
-      note_mode_line_or_margin_highlight (w, x, y, part);
+      note_mode_line_or_margin_highlight (window, x, y, part);
       return;
     }
 
Index: lisp/ruler-mode.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/ruler-mode.el,v
retrieving revision 1.20
diff -u -r1.20 ruler-mode.el
--- lisp/ruler-mode.el  19 Mar 2004 13:15:57 -0000      1.20
+++ lisp/ruler-mode.el  6 May 2004 00:06:20 -0000
@@ -690,6 +690,9 @@
         (aset ruler i ruler-mode-current-column-char)
         (put-text-property
          i (1+ i) 'face 'ruler-mode-current-column-face
+         ruler)
+       (put-text-property
+         i (1+ i) 'mouse-face 'highlight
          ruler))
        ;; Show the `goal-column' marker.
        ((and goal-column (= j goal-column))
Index: lisp/bindings.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/bindings.el,v
retrieving revision 1.130
diff -u -r1.130 bindings.el
--- lisp/bindings.el    1 May 2004 03:50:24 -0000       1.130
+++ lisp/bindings.el    6 May 2004 00:06:20 -0000
@@ -285,7 +285,7 @@
        (dashes (propertize "--" 'help-echo help-echo)))
   (setq-default mode-line-format
     (list
-     (propertize "-" 'help-echo help-echo)
+     (propertize "-" 'help-echo help-echo 'mouse-face 'highlight)
      'mode-line-mule-info
      'mode-line-modified
      'mode-line-frame-identification
@@ -303,6 +303,7 @@
     (list
      (propertize "%[(" 'help-echo help-echo)
      `(:propertize ("" mode-name)
+                  mouse-face highlight
                   help-echo "mouse-2: help for current major mode"
                   local-map ,mode-line-major-mode-keymap)
      '("" mode-line-process)