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Diffstat (limited to 'include/basegfx/tools/keystoplerp.hxx')
-rw-r--r-- | include/basegfx/tools/keystoplerp.hxx | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/include/basegfx/tools/keystoplerp.hxx b/include/basegfx/tools/keystoplerp.hxx new file mode 100644 index 000000000000..8d6d41af63d9 --- /dev/null +++ b/include/basegfx/tools/keystoplerp.hxx @@ -0,0 +1,92 @@ +/* -*- 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 . + */ + +#ifndef _BGFX_TOOLS_KEYSTOPLERP_HXX +#define _BGFX_TOOLS_KEYSTOPLERP_HXX + +#include <basegfx/numeric/ftools.hxx> +#include <vector> +#include <basegfx/basegfxdllapi.h> + +namespace com{ namespace sun{ namespace star{ namespace uno { + template<typename T> class Sequence; +}}}} + +namespace basegfx +{ + namespace tools + { + /** 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 preferrably 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 preferrably 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 ::com::sun::star::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; + }; + } +} + +#endif + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |