63 lines
2.1 KiB
Diff
63 lines
2.1 KiB
Diff
From e288c3045d0c582ee19e85cbe11529dc374d4bbf Mon Sep 17 00:00:00 2001
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From: Peter Hutterer <peter.hutterer@who-t.net>
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Date: Mon, 21 Nov 2016 08:39:47 +1000
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Subject: [PATCH libinput] touchpad: only use the last two coordinates for
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delta calculation
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Taking the last 4 points means factoring in a coordinate that may be more than
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40ms in the past - or even more when the finger moves slowly and we don't get
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events for a while. This makes the pointer more sluggish and slower to catch up
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with what the finger is actually doing.
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We already have the motion hysteresis as a separate item to prevent jumps (and
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thus adds some delay to the movement), the calculation over time doesn't
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provide enough benefit to justify the sluggish pointer.
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Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
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---
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src/evdev-mt-touchpad.c | 20 +++++---------------
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1 file changed, 5 insertions(+), 15 deletions(-)
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diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
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index d72cb19..7b8514c 100644
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--- a/src/evdev-mt-touchpad.c
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+++ b/src/evdev-mt-touchpad.c
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@@ -262,29 +262,19 @@ tp_end_sequence(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
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tp_end_touch(tp, t, time);
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}
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-static double
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-tp_estimate_delta(int x0, int x1, int x2, int x3)
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-{
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- return (x0 + x1 - x2 - x3) / 4.0;
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-}
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-
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struct normalized_coords
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tp_get_delta(struct tp_touch *t)
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{
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struct device_float_coords delta;
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const struct normalized_coords zero = { 0.0, 0.0 };
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- if (t->history.count < TOUCHPAD_MIN_SAMPLES)
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+ if (t->history.count <= 1)
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return zero;
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- delta.x = tp_estimate_delta(tp_motion_history_offset(t, 0)->x,
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- tp_motion_history_offset(t, 1)->x,
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- tp_motion_history_offset(t, 2)->x,
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- tp_motion_history_offset(t, 3)->x);
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- delta.y = tp_estimate_delta(tp_motion_history_offset(t, 0)->y,
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- tp_motion_history_offset(t, 1)->y,
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- tp_motion_history_offset(t, 2)->y,
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- tp_motion_history_offset(t, 3)->y);
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+ delta.x = tp_motion_history_offset(t, 0)->x -
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+ tp_motion_history_offset(t, 1)->x;
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+ delta.y = tp_motion_history_offset(t, 0)->y -
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+ tp_motion_history_offset(t, 1)->y;
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return tp_normalize_delta(t->tp, delta);
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}
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--
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2.9.3
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