Reapply "Fix mouse position handling for nested tty child frames"

This reverts commit e2cc52dbcd196f95cc79c6c6d899b9e86e696fe5.

3 files changed, 31 insertions, 12 deletions

diff --git a/src/dispextern.h b/src/dispextern.h
index 9c193e79fd1..e1214128e35 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -3959,6 +3959,7 @@ void combine_updates_for_frame (struct frame *f, bool inhibit_id_p);
 void tty_raise_lower_frame (struct frame *f, bool raise);
 int max_child_z_order (struct frame *parent);
 void root_xy (struct frame *f, int x, int y, int *rx, int *ry);
+void child_xy (struct frame *f, int x, int y, int *cx, int *cy);
 bool is_frame_ancestor (struct frame *f1, struct frame *f2);
 
 INLINE_HEADER_END
diff --git a/src/dispnew.c b/src/dispnew.c
index 00e59c767e8..5a8064a1a02 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3328,6 +3328,17 @@ root_xy (struct frame *f, int x, int y, int *rx, int *ry)
     }
 }
 
+/* Translate absolute coordinates (X, Y) to coordinates relative to F's origin.  */
+
+void
+child_xy (struct frame *f, int x, int y, int *cx, int *cy)
+{
+  int rx, ry;
+  root_xy (f, 0, 0, &rx, &ry);
+  *cx = x - rx;
+  *cy = y - ry;
+}
+
 /* Return the rectangle frame F occupies.  X and Y are in absolute
    coordinates.  */
 
diff --git a/src/term.c b/src/term.c
index 7397ee68347..e13089af2bb 100644
--- a/src/term.c
+++ b/src/term.c
@@ -2595,7 +2595,7 @@ tty_draw_row_with_mouse_face (struct window *w, struct glyph_row *row,
 #endif
 
 static Lisp_Object
-tty_frame_at (int x, int y)
+tty_frame_at (int x, int y, int *cx, int *cy)
 {
   for (Lisp_Object frames = Ftty_frame_list_z_order (Qnil);
        !NILP (frames);
@@ -2606,24 +2606,33 @@ tty_frame_at (int x, int y)
       int fx, fy;
       root_xy (f, 0, 0, &fx, &fy);
 
-      if (fx <= x && x < fx + f->pixel_width
-          && fy <= y && y < fy + f->pixel_height)
-        return frame;
+      if ((fx <= x && x < fx + f->pixel_width)
+          && (fy <= y && y < fy + f->pixel_height))
+        {
+          child_xy (XFRAME (frame), x, y, cx, cy);
+          return frame;
+        }
     }
 
   return Qnil;
 }
 
-DEFUN ("tty-frame-at", Ftty_frame_at, Stty_frame_at,
-       2, 2, 0,
-       doc: /* Return tty frame containing pixel position X, Y.  */)
+DEFUN ("tty-frame-at", Ftty_frame_at, Stty_frame_at, 2, 2, 0,
+       doc : /* Return tty frame containing absolute pixel position (X, Y).
+Value is nil if no frame found.  Otherwise it is a list (FRAME CX CY),
+where FRAME is the frame containing (X, Y) and CX and CY are X and Y
+relative to FRAME.  */)
   (Lisp_Object x, Lisp_Object y)
 {
   if (! FIXNUMP (x) || ! FIXNUMP (y))
     /* Coordinates this big can not correspond to any frame.  */
     return Qnil;
 
-  return tty_frame_at (XFIXNUM (x), XFIXNUM (y));
+  int cx, cy;
+  Lisp_Object frame = tty_frame_at (XFIXNUM (x), XFIXNUM (y), &cx, &cy);
+  if (NILP (frame))
+    return Qnil;
+  return list3 (frame, make_fixnum (cx), make_fixnum (cy));
 }
 
 #ifdef HAVE_GPM
@@ -2756,11 +2765,9 @@ term_mouse_click (struct input_event *result, Gpm_Event *event,
 int
 handle_one_term_event (struct tty_display_info *tty, const Gpm_Event *event_in)
 {
-  Lisp_Object frame = tty_frame_at (event_in->x, event_in->y);
-  struct frame *f = decode_live_frame (frame);
   Gpm_Event event = *event_in;
-  event.x -= f->left_pos;
-  event.y -= f->top_pos;
+  Lisp_Object frame = tty_frame_at (event_in->x, event_in->y, &event.x, &event.y);
+  struct frame *f = decode_live_frame (frame);
 
   struct input_event ie;
   int count = 0;