flick velocity and deceleration

Helpers/Searcher.qml

@@ -26,7 +26,6 @@ Singleton {
 
 	function query(search: string): list<var> {
 		search = transformSearch(search);
-		console.log(!search, search, ...list);
 		if (!search)
 			return [...list];
 

Plugins/ZShell/Components/carouselview.cpp

@@ -46,7 +46,7 @@ CarouselView::CarouselView(QQuickItem* parent) : QQuickItem(parent) {
 	});
 
 	m_flickAnim = new QVariantAnimation(this);
-	m_flickAnim->setEasingCurve(QEasingCurve::Linear);
+	m_flickAnim->setEasingCurve(QEasingCurve::OutQuad);
 
 	connect(
 		m_flickAnim,
@@ -101,9 +101,8 @@ bool CarouselView::childMouseEventFilter(QQuickItem* item, QEvent* event) {
 
 		m_dragTimer.start();
 
-		m_lastMoveX = pos.x();
+		m_velocitySamples.clear();
-		m_lastMoveT = 0;
+		addVelocitySample(0, pos.x());
-		m_velocity = 0;
 
 		return false;
 	}
@@ -129,17 +128,7 @@ bool CarouselView::childMouseEventFilter(QQuickItem* item, QEvent* event) {
 		updateCurrentIndexFromContentX(true);
 		relayout();
 
-		const qint64 t = m_dragTimer.elapsed();
+		addVelocitySample(m_dragTimer.elapsed(), pos.x());
-		const qint64 dt = t - m_lastMoveT;
-
-		if (dt > 0) {
-			const qreal instVel = (m_lastMoveX - pos.x()) / (dt / 1000.0);
-
-			m_velocity = m_velocity * 0.7 + instVel * 0.3;
-		}
-
-		m_lastMoveX = pos.x();
-		m_lastMoveT = t;
 
 		mouseEvent->accept();
 		return true;
@@ -1141,10 +1130,8 @@ void CarouselView::mousePressEvent(QMouseEvent* event) {
 
 	m_dragTimer.start();
 
-	m_lastMoveX = event->position().x();
+	m_velocitySamples.clear();
-
+	addVelocitySample(0, event->position().x());
-	m_lastMoveT = 0;
-	m_velocity = 0;
 
 	event->accept();
 }
@@ -1170,32 +1157,43 @@ void CarouselView::mouseMoveEvent(QMouseEvent* event) {
 	updateCurrentIndexFromContentX(true);
 	relayout();
 
-	const qint64 t = m_dragTimer.elapsed();
+	addVelocitySample(m_dragTimer.elapsed(), event->position().x());
-
-	const qint64 dt = t - m_lastMoveT;
-
-	if (dt > 0) {
-		const qreal instVel =
-			(m_lastMoveX - event->position().x()) / (dt / 1000.0);
-
-		m_velocity = m_velocity * 0.7 + instVel * 0.3;
-	}
-
-	m_lastMoveX = event->position().x();
-
-	m_lastMoveT = t;
 
 	event->accept();
 }
 
+void CarouselView::addVelocitySample(qint64 t, qreal x) {
+	m_velocitySamples.append({t, x});
+
+	while (m_velocitySamples.size() > 1 &&
+		   t - m_velocitySamples.first().t > kVelocitySampleWindowMs) {
+		m_velocitySamples.removeFirst();
+	}
+}
+
+qreal CarouselView::sampledVelocity() const {
+	if (m_velocitySamples.size() < 2) return 0;
+
+	const VelocitySample& oldest = m_velocitySamples.first();
+	const VelocitySample& newest = m_velocitySamples.last();
+
+	const qreal dt = newest.t - oldest.t;
+
+	if (dt < 8) return 0;
+
+	return (oldest.x - newest.x) / (dt / 1000.0);
+}
+
 void CarouselView::mouseReleaseEvent(QMouseEvent* event) {
 	if (!m_dragging) return;
 
 	m_dragging = false;
 
+	const bool wasDragActive = m_dragActive;
+
 	ungrabMouse();
 
-	if (!m_dragActive) {
+	if (!wasDragActive) {
 		cancelAnimations();
 		snapToNearest();
 
@@ -1205,7 +1203,7 @@ void CarouselView::mouseReleaseEvent(QMouseEvent* event) {
 
 	m_dragActive = false;
 
-	qreal v = qBound(-kMaxFlickVelocity, m_velocity, kMaxFlickVelocity);
+	qreal v = qBound(-kMaxFlickVelocity, sampledVelocity(), kMaxFlickVelocity);
 
 	if (std::abs(v) < kMinFlickVelocity) {
 		snapToNearest();
@@ -1215,24 +1213,17 @@ void CarouselView::mouseReleaseEvent(QMouseEvent* event) {
 	}
 
 	const qreal duration = std::abs(v) / (kFlickFriction * 1000.0);
-
 	const qreal distance = (v * (duration / 1000.0)) / 2.0;
-
 	const qreal rawDest = m_contentX + distance;
-
 	const qreal dest = contentXForIndex(indexForContentX(rawDest));
 
 	cancelAnimations();
 
 	m_flickAnim->setDuration(
 		static_cast<int>(qBound<qreal>(120, duration, 900)));
-
+	m_flickAnim->setEasingCurve(QEasingCurve::OutQuad);
-	m_flickAnim->setEasingCurve(QEasingCurve::OutCubic);
-
 	m_flickAnim->setStartValue(m_contentX);
-
 	m_flickAnim->setEndValue(dest);
-
 	m_flickAnim->start();
 
 	event->accept();

Plugins/ZShell/Components/carouselview.hpp

@@ -10,6 +10,8 @@
 #include <QVariantAnimation>
 #include <QVariantList>
 #include <QVector>
+#include <qtypes.h>
+#include <qvectornd.h>
 
 namespace ZShell::components {
 
@@ -150,6 +152,11 @@ class CarouselView : public QQuickItem {
 		bool active = false;
 	};
 
+	struct VelocitySample {
+		qint64 t;
+		qreal x;
+	};
+
 	void rebuildArrangement();
 	void relayout();
 
@@ -190,6 +197,9 @@ class CarouselView : public QQuickItem {
 	QQuickItem* acquireItem();
 	void releaseAllItems();
 
+	void addVelocitySample(qint64 t, qreal x);
+	qreal sampledVelocity() const;
+
 	QQmlComponent* m_delegate = nullptr;
 	QVariantList m_model;
 	QVariantMap m_delegateProperties;
@@ -226,9 +236,9 @@ class CarouselView : public QQuickItem {
 	qreal m_pressContentX = 0;
 
 	QElapsedTimer m_dragTimer;
-	qreal m_lastMoveX = 0;
+
-	qint64 m_lastMoveT = 0;
+	QVector<VelocitySample> m_velocitySamples;
-	qreal m_velocity = 0;
+	static constexpr qint64 kVelocitySampleWindowMs = 80;
 
 	QVariantAnimation* m_flickAnim = nullptr;