bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

[Visuwesh]

Currently, to know if a mouse button is being pressed, one has to keep
track of state by cleverly utilising [down-mouse-N] and [mouse-N] events
(see [1]).  It is certainly no easy task, it would be really nice if
Emacs had the equivalent of `xinput --query-state <mouse-id>' [2]
(the implementation of which can be found in state.c in xinput's
source).

The reason I ask this is because I would really like to have mouse
chording in Emacs but currently it is too hard to implement it (BTW,
mouse-copy.el talks about mouse-chording).

    1. https://github.com/akrito/acme-mouse
    2. All you need to do is,
           % xinput --query-state <mouse-id> |sed -n 's/[ \t]\+button\[1\]=//p'
       to get the state of mouse-1.

In GNU Emacs 29.0.50 (build 26, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2022-07-22 built on astatine
Repository revision: 12a3137cd381cb743768033e789b900b015041d7
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Debian GNU/Linux bookworm/sid

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bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Visuwesh <visuweshm@gmail.com> writes:

> Currently, to know if a mouse button is being pressed, one has to keep
> track of state by cleverly utilising [down-mouse-N] and [mouse-N] events
> (see [1]).  It is certainly no easy task, it would be really nice if
> Emacs had the equivalent of `xinput --query-state <mouse-id>' [2]
> (the implementation of which can be found in state.c in xinput's
> source).

Relying on the X input extension is not portable, not only outside of
X, but also inside Emacs, which supports being run on X servers where
the input extension is not available.

How about a function that returns a list of mouse buttons currently held
down on a given terminal? That would be very straightforward to
implement.

bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

[Visuwesh]

[செவ்வாய் ஜூலை 26, 2022] Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" wrote:

> Visuwesh <visuweshm@gmail.com> writes:
>
>> Currently, to know if a mouse button is being pressed, one has to keep
>> track of state by cleverly utilising [down-mouse-N] and [mouse-N] events
>> (see [1]).  It is certainly no easy task, it would be really nice if
>> Emacs had the equivalent of `xinput --query-state <mouse-id>' [2]
>> (the implementation of which can be found in state.c in xinput's
>> source).
>
> Relying on the X input extension is not portable, not only outside of
> X, but also inside Emacs, which supports being run on X servers where
> the input extension is not available.
>
> How about a function that returns a list of mouse buttons currently held
> down on a given terminal? That would be very straightforward to
> implement.

That would work just fine with me, thanks.  I pointed out xinput since
that was the first straightforward thing that came up when I searched
the internet.  BTW, it would be nice if the order of the buttons was in
the order they were pressed i.e., if I pressed mouse-1 then mouse-2 the
list would be (mouse-2 mouse-1).

bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Visuwesh <visuweshm@gmail.com> writes:

> BTW, it would be nice if the order of the buttons was in the order
> they were pressed i.e., if I pressed mouse-1 then mouse-2 the list
> would be (mouse-2 mouse-1).

That information is unfortunately not readily available, but can't you
look at `recent-keys'?

bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

[Visuwesh]

[செவ்வாய் ஜூலை 26, 2022] Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" wrote:

> Visuwesh <visuweshm@gmail.com> writes:
>
>> BTW, it would be nice if the order of the buttons was in the order
>> they were pressed i.e., if I pressed mouse-1 then mouse-2 the list
>> would be (mouse-2 mouse-1).
>
> That information is unfortunately not readily available, but can't you
> look at `recent-keys'?

It's not a huge deal breaker, I think.  Thanks for the pointer to
`recent-keys' though.