core/easingcurve: add EasingCurve type

src/core/easingcurve.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <qeasingcurve.h>
+#include <qobject.h>
+#include <qpoint.h>
+#include <qqmlintegration.h>
+#include <qrect.h>
+#include <qtmetamacros.h>
+
+///! Easing curve.
+/// Directly accessible easing curve as used in property animations.
+class EasingCurve: public QObject {
+	Q_OBJECT;
+	/// Easing curve settings. Works exactly the same as
+	/// [PropertyAnimation.easing](https://doc.qt.io/qt-6/qml-qtquick-propertyanimation.html#easing-prop).
+	Q_PROPERTY(QEasingCurve curve READ curve WRITE setCurve NOTIFY curveChanged);
+	QML_ELEMENT;
+
+public:
+	EasingCurve(QObject* parent = nullptr): QObject(parent) {}
+
+	/// Returns the Y value for the given X value on the curve
+	/// from 0.0 to 1.0.
+	Q_INVOKABLE [[nodiscard]] qreal valueAt(qreal x) const;
+	/// Interpolates between two values using the given X coordinate.
+	Q_INVOKABLE [[nodiscard]] qreal interpolate(qreal x, qreal a, qreal b) const;
+	/// Interpolates between two points using the given X coordinate.
+	Q_INVOKABLE [[nodiscard]] QPointF interpolate(qreal x, const QPointF& a, const QPointF& b) const;
+	/// Interpolates two rects using the given X coordinate.
+	Q_INVOKABLE [[nodiscard]] QRectF interpolate(qreal x, const QRectF& a, const QRectF& b) const;
+
+	[[nodiscard]] QEasingCurve curve() const;
+	void setCurve(QEasingCurve curve);
+
+signals:
+	void curveChanged();
+
+private:
+	QEasingCurve mCurve;
+};