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From 89b6d267aec60ded8bf72d78be7237df935c0eb4 Mon Sep 17 00:00:00 2001
From: detiam <dehe_tian@outlook.com>
Date: Wed, 17 Apr 2024 17:55:00 +0800
Subject: [PATCH 1/2] Revert "dix: fix wheel emulation lockup when a negative
increment is set"
This reverts commit d2158d4063dd87e630ca4c853ac07b88f3662c8f.
---
dix/getevents.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/dix/getevents.c b/dix/getevents.c
index c39ef3371..d4441224e 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -1607,9 +1607,9 @@ emulate_scroll_button_events(InternalEvent *events,
/* The next value we want to send out a button event for */
double next_val = last_scroll_val + direction * incr;
- if ((((direction > 0 && incr > 0) || (direction < 0 && incr < 0)) && (next_val > current_val)) ||
- (((direction > 0 && incr < 0) || (direction < 0 && incr > 0)) && (next_val < current_val)))
- break;
+ if ((direction > 0 && next_val > current_val) ||
+ (direction < 0 && next_val < current_val))
+ break;
/* fill_pointer_events() generates four events: one normal and one raw
* event for button press and button release.
--
2.44.0
From 9d89f0cfd4277a19e4afd5b24e6dfd38f2435fed Mon Sep 17 00:00:00 2001
From: detiam <dehe_tian@outlook.com>
Date: Wed, 17 Apr 2024 17:55:10 +0800
Subject: [PATCH 2/2] Revert "dix: switch scroll button emulation to multiples
of increment"
This reverts commit 0a22502c34f2ea9799a67386498f657d769c7af8.
---
dix/getevents.c | 107 +++++++++++-------------------------------------
1 file changed, 24 insertions(+), 83 deletions(-)
diff --git a/dix/getevents.c b/dix/getevents.c
index d4441224e..e9a73981f 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -1500,8 +1500,7 @@ fill_pointer_events(InternalEvent *events, DeviceIntPtr pDev, int type,
* @param type The real type of the event
* @param axis The axis number to generate events for
* @param mask State before this event in absolute coords
- * @param last_valuators The device's last valuators value
- * @param[in,out] lastScroll Last scroll state posted in absolute coords (modified
+ * @param[in,out] last Last scroll state posted in absolute coords (modified
* in-place)
* @param ms Current time in ms
* @param max_events Max number of events to be generated
@@ -1513,19 +1512,15 @@ emulate_scroll_button_events(InternalEvent *events,
int type,
int axis,
const ValuatorMask *mask,
- const ValuatorMask *last_valuators,
- ValuatorMask *lastScroll, CARD32 ms, int max_events)
+ ValuatorMask *last, CARD32 ms, int max_events)
{
AxisInfoPtr ax;
double delta;
double incr;
- int direction = 0; /* -1 for up, 1 for down */
int num_events = 0;
+ double total;
int b;
int flags = 0;
- double last_val, /* abs axis value from previous event */
- current_val, /* abs axis value for this event */
- last_scroll_val; /* abs axis value we sent out the last scroll button for */
if (dev->valuator->axes[axis].scroll.type == SCROLL_TYPE_NONE)
return 0;
@@ -1543,73 +1538,25 @@ emulate_scroll_button_events(InternalEvent *events,
if (type != ButtonPress && type != ButtonRelease)
flags |= POINTER_EMULATED;
- if (!valuator_mask_isset(lastScroll, axis))
- valuator_mask_set_double(lastScroll, axis, 0);
-
- /* The delta between the last value we sent a scroll button event for
- * and the current event value (which has been applied already in
- * fill_pointer_events). This tells us the scroll direction. */
- delta = valuator_mask_get_double(mask, axis) - valuator_mask_get_double(lastScroll, axis);
- direction = delta * incr > 0 ? 1 : -1;
+ if (!valuator_mask_isset(last, axis))
+ valuator_mask_set_double(last, axis, 0);
+ delta =
+ valuator_mask_get_double(mask, axis) - valuator_mask_get_double(last,
+ axis);
+ total = delta;
b = (ax->scroll.type == SCROLL_TYPE_VERTICAL) ? 5 : 7;
- if (direction < 0)
+
+ if ((incr > 0 && delta < 0) || (incr < 0 && delta > 0))
b--; /* we're scrolling up or left → button 4 or 6 */
- /* Note: we emulate scroll on multiples of the increment, regardless of the
- * current delta, mostly for the benefit of Xwayland which doesn't (cannot)
- * distinguish between devices, see #1339 and #1414.
- *
- * Where a device scrolls a fraction of an increment, a subsequent scroll in
- * the other direction did not trigger a scroll event. For example, where
- * the increment is 1.0, the current axis value is 3.0 and a device scrolls
- * down by 0.7 (a), then up by -1.0 (b), no scroll event was emitted:
- * -----|------b--|------a--|----
- * 2.0 3.0 4.0
- * For both events, the last button was sent at 3.0 and since the delta
- * from that is never a full increment, no events were generated.
- * With Xwayland this can happen when we switch between smooth-scroll
- * devices and discrete devices.
- *
- * To avoid this, we now emulate button events whenever we cross a multiple
- * of the scroll increment. For example, for a scroll increment of 1.0
- * we expect events at -2.0, -1.0, 0.0, 1.0, 2.0,...
- *
- * In the above example, we go from 3.0 to 3.7 (no scroll button event),
- * then from 3.7 to 2.7 which triggers a scroll button event because we
- * cross 3.0.
- *
- * This trades off one bug for another. Previously, the first scroll button
- * event after changing direction was always between
- * [increment, 2 * increment). Above example again: the first event would be
- * emulated at 2.0 so the full movement before a button event was actually
- * -1.7.
- *
- * Now, the first scroll button event is always between (0.0, increment).
- * Above example again: the first event would be emulated at 3.0
- * so the full movement before a button event was actually -0.7.
- *
- * This only affects changes of directions. Above example again: the next
- * button event in-direction would've been emulated at 4.0 so only 0.3
- * from the current position.
- */
- last_val = valuator_mask_get_double(last_valuators, axis);
- last_scroll_val = valuator_mask_get_double(lastScroll, axis);
- current_val = valuator_mask_get_double(mask, axis);
-
- /* We're crossing an increment multiple? */
- if ((current_val < last_scroll_val && last_scroll_val < last_val) ||
- (last_val < last_scroll_val && last_scroll_val < current_val)) {
- last_scroll_val -= direction * incr;
- }
+ while (fabs(delta) >= fabs(incr)) {
+ int nev_tmp;
- while (TRUE) {
- /* The next value we want to send out a button event for */
- double next_val = last_scroll_val + direction * incr;
-
- if ((direction > 0 && next_val > current_val) ||
- (direction < 0 && next_val < current_val))
- break;
+ if (delta > 0)
+ delta -= fabs(incr);
+ else if (delta < 0)
+ delta += fabs(incr);
/* fill_pointer_events() generates four events: one normal and one raw
* event for button press and button release.
@@ -1617,8 +1564,6 @@ emulate_scroll_button_events(InternalEvent *events,
* for. In that case, we keep decreasing delta, but skip events.
*/
if (num_events + 4 < max_events) {
- int nev_tmp;
-
if (type != ButtonRelease) {
nev_tmp = fill_pointer_events(events, dev, ButtonPress, b, ms,
flags, NULL);
@@ -1632,11 +1577,14 @@ emulate_scroll_button_events(InternalEvent *events,
num_events += nev_tmp;
}
}
- /* send out scroll event */
- last_scroll_val = next_val;
}
- valuator_mask_set_double(lastScroll, axis, last_scroll_val);
+ /* We emulated, update last.scroll */
+ if (total != delta) {
+ total -= delta;
+ valuator_mask_set_double(last, axis,
+ valuator_mask_get_double(last, axis) + total);
+ }
return num_events;
}
@@ -1666,7 +1614,6 @@ GetPointerEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
{
CARD32 ms = GetTimeInMillis();
int num_events = 0, nev_tmp;
- ValuatorMask last_valuators;
ValuatorMask mask;
ValuatorMask scroll;
int i;
@@ -1695,12 +1642,6 @@ GetPointerEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
valuator_mask_copy(&mask, mask_in);
- /* Back up the current value of last.valuators. fill_pointer_events()
- * overwrites those but we need them for scroll button emulation */
- valuator_mask_zero(&last_valuators);
- for (size_t idx = 0; idx < pDev->last.numValuators; idx++)
- valuator_mask_set_double(&last_valuators, idx, pDev->last.valuators[idx]);
-
/* Turn a scroll button press into a smooth-scrolling event if
* necessary. This only needs to cater for the XIScrollFlagPreferred
* axis (if more than one scrolling axis is present) */
@@ -1771,7 +1712,7 @@ GetPointerEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
nev_tmp =
emulate_scroll_button_events(events, pDev, realtype, i, &scroll,
- &last_valuators, pDev->last.scroll, ms,
+ pDev->last.scroll, ms,
GetMaximumEventsNum() - num_events);
events += nev_tmp;
num_events += nev_tmp;
--
2.44.0
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