[Emacs-diffs] emacs-24 r117203: Attempt to solve bug #17497 by minimizing cursor motion during TTY menu updates.

[Eli Zaretskii]

------------------------------------------------------------
revno: 117203
revision-id: address@hidden
parent: address@hidden
fixes bug: http://debbugs.gnu.org/17497
committer: Eli Zaretskii <address@hidden>
branch nick: emacs-24
timestamp: Wed 2014-06-04 12:16:46 +0300
message:
  Attempt to solve bug #17497 by minimizing cursor motion during TTY menu 
updates.
  
   src/term.c (tty_menu_display): Don't position cursor here.  Instead,
   pass the cursor coordinates to update_frame_with_menu.
   (tty_menu_activate): Send the hide cursor command only once in an
   iteration through the outer 'while' loop.
   src/dispnew.c (update_frame_1): Accept an additional argument
   SET_CURSOR_P, and position the cursor at the end of the frame
   update only if that argument is non-zero.  All callers changed to
   provide the additional argument as non-zero, except for
   update_frame_with_menu.
   (update_frame_with_menu): Accept 2 additional arguments ROW and
   COL; if they are non-negative, instruct update_frame_1 not to
   position the cursor, and instead position it according to ROW and
   COL.
   src/dispextern.h (update_frame_with_menu): Update prototype.
modified:
  src/ChangeLog                  changelog-20091113204419-o5vbwnq5f7feedwu-1438
  src/dispextern.h               
dispextern.h-20091113204419-o5vbwnq5f7feedwu-218
  src/dispnew.c                  dispnew.c-20091113204419-o5vbwnq5f7feedwu-258
  src/term.c                     term.c-20091113204419-o5vbwnq5f7feedwu-220

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2014-06-02 18:42:07 +0000
+++ b/src/ChangeLog     2014-06-04 09:16:46 +0000
@@ -1,3 +1,23 @@
+2014-06-04  Eli Zaretskii  <address@hidden>
+
+       Minimize cursor motion during TTY menu updates.
+       * term.c (tty_menu_display): Don't position cursor here.  Instead,
+       pass the cursor coordinates to update_frame_with_menu.
+       (tty_menu_activate): Send the hide cursor command only once in an
+       iteration through the outer 'while' loop.
+
+       * dispnew.c (update_frame_1): Accept an additional argument
+       SET_CURSOR_P, and position the cursor at the end of the frame
+       update only if that argument is non-zero.  All callers changed to
+       provide the additional argument as non-zero, except for
+       update_frame_with_menu.
+       (update_frame_with_menu): Accept 2 additional arguments ROW and
+       COL; if they are non-negative, instruct update_frame_1 not to
+       position the cursor, and instead position it according to ROW and
+       COL.
+
+       * dispextern.h (update_frame_with_menu): Update prototype.
+
 2014-06-02  Stefan Monnier  <address@hidden>
 
        * callproc.c (call_process): Don't check read-only if we don't insert

=== modified file 'src/dispextern.h'
--- a/src/dispextern.h  2014-02-04 07:36:58 +0000
+++ b/src/dispextern.h  2014-06-04 09:16:46 +0000
@@ -3454,7 +3454,7 @@
                                          int *, int *, int *, int *);
 extern void redraw_frame (struct frame *);
 extern bool update_frame (struct frame *, bool, bool);
-extern void update_frame_with_menu (struct frame *);
+extern void update_frame_with_menu (struct frame *, int, int);
 extern void bitch_at_user (void);
 extern void adjust_frame_glyphs (struct frame *);
 void free_glyphs (struct frame *);

=== modified file 'src/dispnew.c'
--- a/src/dispnew.c     2014-06-02 16:53:02 +0000
+++ b/src/dispnew.c     2014-06-04 09:16:46 +0000
@@ -92,7 +92,7 @@
 static void mirror_line_dance (struct window *, int, int, int *, char *);
 static bool update_window_tree (struct window *, bool);
 static bool update_window (struct window *, bool);
-static bool update_frame_1 (struct frame *, bool, bool);
+static bool update_frame_1 (struct frame *, bool, bool, bool);
 static bool scrolling (struct frame *);
 static void set_window_cursor_after_update (struct window *);
 static void adjust_frame_glyphs_for_window_redisplay (struct frame *);
@@ -3070,7 +3070,7 @@
 
       /* Update the display  */
       update_begin (f);
-      paused_p = update_frame_1 (f, force_p, inhibit_hairy_id_p);
+      paused_p = update_frame_1 (f, force_p, inhibit_hairy_id_p, 1);
       update_end (f);
 
       if (FRAME_TERMCAP_P (f) || FRAME_MSDOS_P (f))
@@ -3100,12 +3100,17 @@
    glyphs.  This is like the second part of update_frame, but it
    doesn't call build_frame_matrix, because we already have the
    desired matrix prepared, and don't want it to be overwritten by the
-   text of the normal display.  */
+   text of the normal display.
+
+   ROW and COL, if non-negative, are the row and column of the TTY
+   frame where to position the cursor after the frame update is
+   complete.  Negative values mean ask update_frame_1 to position the
+   cursor "normally", i.e. at point in the selected window.  */
 void
-update_frame_with_menu (struct frame *f)
+update_frame_with_menu (struct frame *f, int row, int col)
 {
   struct window *root_window = XWINDOW (f->root_window);
-  bool paused_p;
+  bool paused_p, cursor_at_point_p;
 
   eassert (FRAME_TERMCAP_P (f));
 
@@ -3115,9 +3120,14 @@
 
   /* Update the display.  */
   update_begin (f);
+  cursor_at_point_p = !(row >= 0 && col >= 0);
   /* Force update_frame_1 not to stop due to pending input, and not
      try scrolling.  */
-  paused_p = update_frame_1 (f, 1, 1);
+  paused_p = update_frame_1 (f, 1, 1, cursor_at_point_p);
+  /* ROW and COL tell us where in the menu to position the cursor, so
+     that screen readers know the active region on the screen.  */
+  if (!cursor_at_point_p)
+    cursor_to (f, row, col);
   update_end (f);
 
   if (FRAME_TTY (f)->termscript)
@@ -4413,12 +4423,14 @@
 /* Update the desired frame matrix of frame F.
 
    FORCE_P means that the update should not be stopped by pending input.
-   INHIBIT_HAIRY_ID_P means that scrolling should not be tried.
+   INHIBIT_ID_P means that scrolling by insert/delete should not be tried.
+   SET_CURSOR_P false means do not set cursor at point in selected window.
 
    Value is true if update was stopped due to pending input.  */
 
 static bool
-update_frame_1 (struct frame *f, bool force_p, bool inhibit_id_p)
+update_frame_1 (struct frame *f, bool force_p, bool inhibit_id_p,
+               bool set_cursor_p)
 {
   /* Frame matrices to work on.  */
   struct glyph_matrix *current_matrix = f->current_matrix;
@@ -4490,7 +4502,7 @@
   pause_p = 0 < i && i < FRAME_LINES (f) - 1;
 
   /* Now just clean up termcap drivers and set cursor, etc.  */
-  if (!pause_p)
+  if (!pause_p && set_cursor_p)
     {
       if ((cursor_in_echo_area
           /* If we are showing a message instead of the mini-buffer,

=== modified file 'src/term.c'
--- a/src/term.c        2014-05-01 15:59:42 +0000
+++ b/src/term.c        2014-06-04 09:16:46 +0000
@@ -2907,8 +2907,7 @@
       display_tty_menu_item (menu->text[j], max_width, face, x, y + i,
                             menu->submenu[j] != NULL);
     }
-  update_frame_with_menu (sf);
-  cursor_to (sf, row, col);
+  update_frame_with_menu (sf, row, col);
 }
 
 /* --------------------------- X Menu emulation ---------------------- */
@@ -3079,7 +3078,7 @@
 screen_update (struct frame *f, struct glyph_matrix *mtx)
 {
   restore_desired_matrix (f, mtx);
-  update_frame_with_menu (f);
+  update_frame_with_menu (f, -1, -1);
 }
 
 typedef enum {
@@ -3228,7 +3227,7 @@
 
   /* Force update of the current frame, so that the desired and the
      current matrices are identical.  */
-  update_frame_with_menu (sf);
+  update_frame_with_menu (sf, -1, -1);
   state[0].menu = menu;
   state[0].screen_behind = save_and_enable_current_matrix (sf);
 
@@ -3373,8 +3372,6 @@
                            state[statecount - 1].y,
                            state[statecount - 1].pane,
                            faces, x, y, first_item, 1);
-         tty_hide_cursor (tty);
-         fflush (tty->output);
          /* The call to display help-echo below will move the cursor,
             so remember its current position as computed by
             tty_menu_display.  */
@@ -3393,10 +3390,13 @@
             item, so that screen readers and other accessibility aids
             know where the active region is.  */
          cursor_to (sf, row, col);
-         tty_hide_cursor (tty);
-         fflush (tty->output);
          prev_menu_help_message = menu_help_message;
        }
+      /* Both tty_menu_display and help_callback invoke update_end,
+        which calls tty_show_cursor.  Re-hide it, so it doesn't show
+        through the menus.  */
+      tty_hide_cursor (tty);
+      fflush (tty->output);
     }
 
   sf->mouse_moved = 0;