* termhooks.h (struct input_event): Doc fix.

	(NUM_MOUSE_BUTTONS): New constant.
	(click_modifier): New modifier.
	(NUM_MODIFIER_COMBOS): Removed.

1 files changed, 24 insertions, 9 deletions

diff --git a/src/termhooks.h b/src/termhooks.h
index 10d303100c4..695c5a316e5 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -101,7 +101,9 @@ struct input_event {
                                    was typed.
                                    .timestamp gives a timestamp (in
                                    milliseconds) for the keystroke.  */
-    mouse_click,                /* The button number is in .code.
+    mouse_click,                /* The button number is in .code; it must
+                                   be >= 0 and < NUM_MOUSE_BUTTONS, defined
+                                   below.
                                    .modifiers holds the state of the
                                    modifier keys.
                                    .x and .y give the mouse position,
@@ -153,25 +155,38 @@ struct input_event {
   unsigned long timestamp;
 };
 
+/* This is used in keyboard.c, to tell how many buttons we will need
+   to track the positions of.  */
+#define NUM_MOUSE_BUTTONS (5)
+
 /* Bits in the modifiers member of the input_event structure.
    Note that reorder_modifiers assumes that the bits are in canonical
-   order.  */
+   order.  
+
+   The modifiers applied to mouse clicks are rather ornate.  The
+   window-system-specific code should store mouse clicks with
+   up_modifier or down_modifier set; the window-system independent
+   code turns all up_modifier events into either drag_modifier or
+   click_modifier.  The click_modifier has no written representation
+   in the names of the symbols used as event heads, but it does appear
+   in the Qevent_symbol_components property of the event heads.  */
 enum {
-  up_modifier   =   1,          /* This only applies to mouse buttons.  */
+  up_modifier   =   1,          /* Only used on mouse buttons - always
+                                   turned into a click or a drag modifier
+                                   before lisp code sees the event.  */
   alt_modifier  =   2,          /* Under X, the XK_Alt_[LR] keysyms.  */
   ctrl_modifier =   4,
   hyper_modifier=   8,          /* Under X, the XK_Hyper_[LR] keysyms.  */
   meta_modifier =  16,          /* Under X, the XK_Meta_[LR] keysyms.  */
   shift_modifier=  32,
   super_modifier=  64,          /* Under X, the XK_Super_[LR] keysyms.  */
-  down_modifier = 128,          /* The window-system independent code finds
-                                   it handy to have this modifier, but
-                                   it is ignored in the event queue.  */
-  drag_modifier = 256,          /* Same as down_modifier.  */
+  down_modifier = 128,          /* Only used on mouse buttons.  */
+  drag_modifier = 256,          /* This is never used in the event
+                                   queue; it's only used internally by
+                                   the window-system-independent code.  */
+  click_modifier= 512,          /* See drag_modifier.  */
   last_modifier                 /* This should always be one more than the
                                    highest modifier bit defined.  */
 };
 
-#define NUM_MODIFIER_COMBOS ((last_modifier-1) << 1)
-
 #endif