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| author | Peter Hutterer <peter.hutterer@who-t.net> | 2021-03-10 16:46:43 +1000 |
|---|---|---|
| committer | Peter Hutterer <peter.hutterer@who-t.net> | 2021-03-24 14:44:47 +1000 |
| commit | b8f90d074ef97ba1020b0916cd625061e921cd77 (patch) | |
| tree | 20dd36ecb94f33dae0def35f147a7b7186bbd919 | |
| parent | 7624497df5bffed01007ffaa9099290e5bca528b (diff) | |
| download | libinput-b8f90d074ef97ba1020b0916cd625061e921cd77.tar.gz | |
doc/user: explain why we are doing motion normalization
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit 2f8dab4537dda4205763ef2a48f298da9765a408)
| -rw-r--r-- | doc/user/normalization-of-relative-motion.rst | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/doc/user/normalization-of-relative-motion.rst b/doc/user/normalization-of-relative-motion.rst index 99c62f80..b7059bee 100644 --- a/doc/user/normalization-of-relative-motion.rst +++ b/doc/user/normalization-of-relative-motion.rst @@ -27,6 +27,11 @@ libinput applies a dpi-dependent acceleration function. At low speeds, a movement speed increases, acceleration is applied - at high speeds a low-dpi device will roughly feel the same as a higher-dpi mouse. +The reason for the normalization is convenience: a caller can assume that a +delta of 1 should result in a movement of 1 pixel on a traditional +(low-dpi) screen. On screens with high resolutions, the caller must scale +according to the UI scale factors. + This normalization only applies to accelerated coordinates, unaccelerated coordinates are left in device-units. It is up to the caller to interpret those coordinates correctly. |