bug#28658: 27.0.50; [PATCH] double/triple clicking in xterm-mouse-mode doesn't respect mouse position

[Alex <agrambot@gmail.com>]

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Eli Zaretskii <eliz@gnu.org> writes:

>> From: Alex <agrambot@gmail.com>
>> Cc: 28658@debbugs.gnu.org
>> Date: Thu, 05 Oct 2017 18:14:39 -0600
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> 
>> >> @@ -290,12 +292,14 @@ xterm-mouse-event
>> >>                (xterm-mouse--set-click-count event click-count)))
>> >>             ((not last-time) nil)
>> >>             ((and (> double-click-time (* 1000 (- this-time last-time)))
>> >> +                 (eq x last-x)
>> >> +                 (eq y last-y)
>> >
>> > IMO, 'eq' is not right here: this test should obey the value of
>> > double-click-fuzz, whose units on TTY frames are 1/8 of a character.
>> 
>> I don't understand how to use double-click-fuzz in TTY frames. You said
>> that TTY frames can't discern screen position differences of less than a
>> character, so then why are the units 1/8th of a character?
>
> I don't know why the units are 1/8th of a character, perhaps so that a
> user could set the same value for both GUI and TTY frames.  In any
> case, dividing the value of double-click-fuzz by 8 before comparing
> with coordinate differences is easy enough, no?

Yes, I was just confused about the units, but that makes sense. Though
in my GTK Emacs, (frame-char-width) returns 9 instead of 8 for me...

Anyway, here's the patch:


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From e9c7aca2ade951e03f67db66bb8d2608d740936d Mon Sep 17 00:00:00 2001
From: Alexander Gramiak <agrambot@gmail.com>
Date: Sat, 30 Sep 2017 15:47:56 -0600
Subject: [PATCH] Increase xterm click count only within double-click-fuzz

* lisp/xt-mouse.el (xterm-mouse-event): Save the last click's position
and check it against the current click's position.
---
 lisp/xt-mouse.el | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lisp/xt-mouse.el b/lisp/xt-mouse.el
index d268e1a3fe..d704cfa4e8 100644
--- a/lisp/xt-mouse.el
+++ b/lisp/xt-mouse.el
@@ -278,6 +278,8 @@ xterm-mouse-event
                (last-name (symbol-name last-type))
                (last-time (nth 1 last-click))
                (click-count (nth 2 last-click))
+               (last-x (nth 3 last-click))
+               (last-y (nth 4 last-click))
                (this-time (float-time))
                (name (symbol-name type)))
           (cond
@@ -292,12 +294,16 @@ xterm-mouse-event
                  double-click-time
                  (or (eq double-click-time t)
                      (> double-click-time (* 1000 (- this-time last-time))))
+                 (<= (abs (- x last-x))
+                     (/ double-click-fuzz 8))
+                 (<= (abs (- y last-y))
+                     (/ double-click-fuzz 8))
                  (equal last-name (replace-match "" t t name)))
             (setq click-count (1+ click-count))
             (xterm-mouse--set-click-count event click-count))
            (t (setq click-count 1)))
           (set-terminal-parameter nil 'xterm-mouse-last-click
-                                  (list type this-time click-count)))
+                                  (list type this-time click-count x y)))
 
         (set-terminal-parameter nil 'xterm-mouse-x x)
         (set-terminal-parameter nil 'xterm-mouse-y y)
-- 
2.14.2