Starting with kernel v5.0 two new axes are available for high-resolution wheel
scrolling: REL_WHEEL_HI_RES and REL_HWHEEL_HI_RES. Both axes send data in
fractions of 120 where each multiple of 120 amounts to one logical scroll
event. Fractions of 120 indicate a wheel movement less than one detent.
This commit adds a new API for scroll events. Three new event types that encode
the axis source in the event type name and a new API to get a normalized-to-120
value that also used by Windows and the kernel (each multiple of 120 represents
a logical scroll click).
This addresses a main shortcoming with the existing API - it was unreliable to
calculate the click angle based on the axis value+discrete events and thus any
caller using the axis value alone would be left with some ambiguity. With the
v120 API it's now possible to (usually) calculate the click angle, but more
importantly it provides the simplest hw-independent way of scrolling by a
click or a fraction of a click.
A new event type is required, the only way to integrate the v120 value
otherwise was to start sending events with a discrete value of 0. This
would break existing xf86-input-libinput (divide by zero, fixed in 0.28.2) and
weston (general confusion). mutter, kwin are unaffected.
With the new API, the old POINTER_AXIS event are deprecated - callers should use
the new API where available and discard any POINTER_AXIS events.
Notable: REL_WHEEL/REL_HWHEEL are emulated by the kernel but there's no
guarantee that they'll come every accumulated 120 values, e.g. Logitech mice
often send events that don't add up to 120 per detent.
We use the kernel's wheel click emulation instead of doing our own.
libinput guarantees high-resolution events even on pre-5.0 kernels.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Scroll button locking is an accessibility feature. When enabled, the scroll
button does not need to be held down, the first click holds it logically down,
to be released on the second click of that same button.
This is implemented as simple event filter, so we still get the same behavior
from the emulated logical button, i.e. a physical double click results in a
single logical click of that button provided no scrolling was triggered.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This is a large commit because it's difficult to split this up and we don't
care about bisecting here anyway.
doxygen is going to produce the API documentation only
sphinx is going to produce the prose user (and a bit of developer) documentation.
The source split is doc/api and doc/user.
Steps performed:
- run the doxygen-to-sphinx.sh script to convert all .dox sources to .rst
- manually fixed the .rst to render correctly
- add a few extra .rst documents to generate the right hierarchy
- hook up sphinx-build in meson
- add a new @mainpage for doxygen more aimed at developers
For the build directory:
- sphinx produces /Documentation
- doxygen now produces /api/
These need to be manually combined in the wayland-web repo, meson doesn't
support subdirectories as output paths within the build dir and the
documentation doesn't need to be installed anywhere.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
