apply curve smoothing to drawn lines

Drawers/Interactions.qml

@@ -187,10 +187,7 @@ Item {
 					return;
 				}
 
-				if (!drawingHandler.point.pressedButtons) {
-					root.drawing.content.showHover(x, y);
-					return;
-				}
+				root.drawing.content.showHover(x, y);
 			}
 
 			if (!root.visibilities.bar && Config.barConfig.autoHide && y < root.bar.implicitHeight)

Plugins/ZShell/Internal/strokecanvasitem.cpp

@@ -97,9 +97,31 @@ void StrokeCanvasItem::beginStroke(qreal x, qreal y) {
 }
 
 void StrokeCanvasItem::appendPoint(qreal x, qreal y) {
-	if (shouldAddPoint(m_currentStroke.points, {x, y}, 2.0))
-		m_currentStroke.points.append({x, y});
+	const QPointF incoming{x, y};
 
+	if (!shouldAddPoint(m_currentStroke.points, incoming, 2.0))
+		return;
+
+	QPointF smoothed;
+	if (m_currentStroke.points.isEmpty()) {
+		smoothed = incoming;
+	} else {
+		const QPointF last = m_currentStroke.points.last();
+		const QPointF delta = incoming - last;
+		const qreal dist = std::sqrt(QPointF::dotProduct(delta, delta));
+
+		constexpr qreal minDist = 6.0;
+		constexpr qreal maxDist = 20.0;
+		constexpr qreal minAlpha = 0.1;
+		constexpr qreal maxAlpha = 0.3;
+
+		const qreal t = std::clamp((dist - minDist) / (maxDist - minDist), 0.0, 1.0);
+		const qreal alpha = minAlpha + t * (maxAlpha - minAlpha);
+
+		smoothed = last * (1.0 - alpha) + incoming * alpha;
+	}
+
+	m_currentStroke.points.append(smoothed);
 	update();
 }
 

Plugins/ZShell/Internal/strokecanvasrenderer.cpp

@@ -25,14 +25,31 @@ static void drawStroke(
 		return;
 	}
 
+	auto catmullToBezier = [](
+		const QPointF &p0, const QPointF &p1,
+		const QPointF &p2, const QPointF &p3,
+		float tension,
+		QPointF &cp1, QPointF &cp2)
+			       {
+				       cp1 = p1 + (p2 - p0) * tension / 3.0f;
+				       cp2 = p2 - (p3 - p1) * tension / 3.0f;
+			       };
+
+	const float tension = 0.5f; // increase toward 1.0 for tighter curves
+
 	painter->beginPath();
 	painter->moveTo(points[0]);
 
-	for (int i = 1; i < points.size() - 1; ++i) {
-		QPointF mid = (points[i] + points [i + 1]) / 2;
-		painter->quadraticCurveTo(points[i], mid);
+	for (int i = 0; i < points.size() - 1; ++i) {
+		const QPointF &p0 = points[qMax(i - 1, 0)];
+		const QPointF &p1 = points[i];
+		const QPointF &p2 = points[i + 1];
+		const QPointF &p3 = points[qMin(i + 2, points.size() - 1)];
+
+		QPointF cp1, cp2;
+		catmullToBezier(p0, p1, p2, p3, tension, cp1, cp2);
+		painter->bezierCurveTo(cp1, cp2, p2);
 	}
-	painter->lineTo(points.last());
 
 	painter->stroke();
 }