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author | Peter Hutterer <peter.hutterer@who-t.net> | 2021-03-10 16:46:43 +1000 |
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committer | Peter Hutterer <peter.hutterer@who-t.net> | 2021-03-16 21:29:56 +0000 |
commit | 2f8dab4537dda4205763ef2a48f298da9765a408 (patch) | |
tree | 627ab1482015648bfe2d826bfe373d6fd7ee978c /doc | |
parent | 1d0dbd2461e49c903cdf03c6841c34450cf70dbf (diff) | |
download | libinput-2f8dab4537dda4205763ef2a48f298da9765a408.tar.gz |
doc/user: explain why we are doing motion normalization
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Diffstat (limited to 'doc')
-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. |