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#66655
29.1; Clicking buttons sometimes doesn't work
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Message #79 received at 66655 <at> debbugs.gnu.org (full text, mbox):
>> Where do you see that?
> In the test for the equal buffer position.
The old code did:
if (! (0 < double_click_fuzz
&& - double_click_fuzz < xdiff
&& xdiff < double_click_fuzz
&& - double_click_fuzz < ydiff
&& ydiff < double_click_fuzz
/* Maybe the mouse has moved a lot, caused scrolling, and
eventually ended up at the same screen position (but
not buffer position) in which case it is a drag, not
a click. */
/* FIXME: OTOH if the buffer position has changed
because of a timer or process filter rather than
because of mouse movement, it should be considered as
a click. But mouse-drag-region completely ignores
this case and it hasn't caused any real problem, so
it's probably OK to ignore it as well. */
&& (EQ (Fcar (Fcdr (start_pos)),
Fcar (Fcdr (position))) /* Same buffer pos */
|| !EQ (Fcar (start_pos),
Fcar (position))))) /* Different window */
which in short is approximately:
if (! (!mouse_has_moved
&& (EQ (Fcar (Fcdr (start_pos)),
Fcar (Fcdr (position)))
|| !EQ (Fcar (start_pos),
Fcar (position)))))
If we apply deMorgan we get:
if (mouse_has_moved
|| !(EQ (Fcar (Fcdr (start_pos)),
Fcar (Fcdr (position)))
|| !EQ (Fcar (start_pos),
Fcar (position)))))
apply deMorgan again we get:
if (mouse_has_moved
|| (!EQ (Fcar (Fcdr (start_pos)),
Fcar (Fcdr (position)))
&& EQ (Fcar (start_pos),
Fcar (position)))))
I changed it to:
if (mouse_has_moved
&& (!EQ (Fcar (Fcdr (start_pos)),
Fcar (Fcdr (position))))
&& EQ (Fcar (start_pos), Fcar (position)))
The main purpose of the change is to address the "FIXME" in the comment:
if the mouse hasn't moved, I don't think we should generate a `drag`
even if the buffer content under the mouse has changed.
So, IIUC, what you were saying is that with the new code, a small
movement that goes from one buffer position to another both of which are
within the fuzz will be considered as a click whereas with the current
code it will be a `drag`. Maybe that's worse than the "FIXME" issue it
tries to address?
The other part of the change is the handling of `EQ (Fcar (start_pos),
Fcar (position))` and I must admit I don't know what to do with it, so
this part of the change is largely arbitrary: I don't know why we
currently check this condition nor why we only check it when mouse has
not moved.
Stefan
This bug report was last modified 1 year and 232 days ago.
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