How to set the single click speed?

Karl Auer kauer at
Fri Jan 22 16:18:30 UTC 2016

On Fri, 2016-01-22 at 16:11 +0100, Liam Proven wrote:
> Rapid random movements in optical mice is a sign that a hair or other
> fibre is trapped in the niche where the lens is housed on the
> underside of the device.

Yes. Some surfaces don't work well or at all, either, or work with some
mice and not others (wavelength?).

But none of those things explain the click issues.

Standard mice are unbelievably simple critters. They send short messages
about basic events, and the smarts are in the software. The messages are
just the current button states, delta X and delta Y - the software has
to figure out if buttons have gone down, have gone up, or are still down
(or still up). A "click" doesn't really exist for the mouse itself. A
click is "button X down" plus "button X up" with no more than some
configurable time in between, and provided the mouse hasn't moved too
far between the two button state changes - all of which is up to the
software to work out.

The software turns the primitive mouse messages into "events" and makes
them available to software - so when button X gets pressed and released
within a certain period, the software will send a button X down event, a
button X up event and a button X clicked event. A double click causes
all that twice, plus a double-click event. Most mouse APIs include the
current mouse position with every event, but the mouse itself has no
idea where it is - the software tracks the mouse position by
accumulating every movement.

There is hardware debounce in the mouse, but that's about it. Smart mice
- programmable gaming mice - can be told to synthesise sequences of
these message, and some are keyboards as well as mice (because USB) or
have other not-really-mousey features, but as far as the actual mousing
about is concerned, it's all very primitive stuff.

Regards, K.

[1] When I was writing mouse drivers, the unit of distance for mouse
movement was the "mickey". In these days of far higher resolution mice,
the unit may be something else - micromickeys?

Karl Auer (kauer at

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