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diff --git a/include/basegfx/utils/keystoplerp.hxx b/include/basegfx/utils/keystoplerp.hxx
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+++ b/include/basegfx/utils/keystoplerp.hxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#pragma once
+
+#include <vector>
+#include <basegfx/basegfxdllapi.h>
+
+namespace com::sun::star::uno {
+    template<typename T> class Sequence;
+}
+
+namespace basegfx::utils
+{
+        /** Lerp in a vector of key stops
+
+            This class holds a key stop vector and provides the
+            functionality to lerp inside it. Useful e.g. for
+            multi-stop gradients, or the SMIL key time activity.
+
+            For those, given a global [0,1] lerp alpha, one need to
+            find the suitable bucket index from key stop vector, and
+            then calculate the relative alpha between the two buckets
+            found.
+         */
+        class BASEGFX_DLLPUBLIC KeyStopLerp
+        {
+        public:
+            typedef std::pair<std::ptrdiff_t,double> ResultType;
+
+            /** Create lerper with given vector of stops
+
+                @param rKeyStops
+
+                Vector of stops, must contain at least two elements
+                (though preferably more, otherwise you probably don't
+                need key stop lerping in the first place). All
+                elements must be of monotonically increasing value.
+             */
+            explicit KeyStopLerp( const std::vector<double>& rKeyStops );
+
+            /** Create lerper with given sequence of stops
+
+                @param rKeyStops
+
+                Sequence of stops, must contain at least two elements
+                (though preferably more, otherwise you probably don't
+                need key stop lerping in the first place). All
+                elements must be of monotonically increasing value.
+             */
+            explicit KeyStopLerp( const css::uno::Sequence<double>& rKeyStops );
+
+            /** Find two nearest bucket index & interpolate
+
+                @param fAlpha
+                Find bucket index i, with keyStops[i] < fAlpha <=
+                keyStops[i+1]. Return new alpha value in [0,1),
+                proportional to fAlpha's position between keyStops[i]
+                and keyStops[i+1]
+             */
+            ResultType lerp(double fAlpha) const;
+
+        private:
+            std::vector<double>    maKeyStops;
+            mutable std::ptrdiff_t mnLastIndex;
+        };
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */