49e37a1c3d
Change-Id: If22569a1b7d53fc1b5b87f7ec7d262ebb260e798 Reviewed-on: https://gerrit.libreoffice.org/83933 Tested-by: Jenkins Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
116 lines
2.8 KiB
C++
116 lines
2.8 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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#ifndef INCLUDED_VCL_RESAMPLEKERNEL_HXX
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#define INCLUDED_VCL_RESAMPLEKERNEL_HXX
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#include <boost/math/special_functions/sinc.hpp>
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namespace vcl {
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// Resample kernels
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class Kernel
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{
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public:
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Kernel() {}
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virtual ~Kernel() {}
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virtual double GetWidth() const = 0;
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virtual double Calculate( double x ) const = 0;
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};
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class Lanczos3Kernel final : public Kernel
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{
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public:
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Lanczos3Kernel() : Kernel () {}
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virtual double GetWidth() const override { return 3.0; }
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virtual double Calculate (double x) const override
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{
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return (-3.0 <= x && x < 3.0) ? SincFilter(x) * SincFilter( x / 3.0 ) : 0.0;
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}
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static double SincFilter(double x)
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{
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if (x == 0.0)
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{
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return 1.0;
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}
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x = x * M_PI;
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return boost::math::sinc_pi(x, SincPolicy());
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}
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private:
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typedef boost::math::policies::policy<
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boost::math::policies::promote_double<false> > SincPolicy;
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};
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class BicubicKernel final : public Kernel
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{
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public:
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BicubicKernel() : Kernel () {}
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private:
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virtual double GetWidth() const override { return 2.0; }
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virtual double Calculate (double x) const override
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{
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if (x < 0.0)
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{
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x = -x;
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}
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if (x <= 1.0)
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{
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return (1.5 * x - 2.5) * x * x + 1.0;
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}
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else if (x < 2.0)
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{
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return ((-0.5 * x + 2.5) * x - 4) * x + 2;
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}
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return 0.0;
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}
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};
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class BilinearKernel final : public Kernel
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{
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public:
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BilinearKernel() : Kernel () {}
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private:
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virtual double GetWidth() const override { return 1.0; }
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virtual double Calculate (double x) const override
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{
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if (x < 0.0)
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{
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x = -x;
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}
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if (x < 1.0)
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{
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return 1.0-x;
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}
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return 0.0;
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}
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};
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} // namespace vcl
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#endif // INCLUDED_VCL_RESAMPLEKERNEL_HXX
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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