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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 .
*/
#include <basegfx/utils/keystoplerp.hxx>
#include <com/sun/star/uno/Sequence.hxx>
#include <osl/diagnose.h>
#include <algorithm>
static void validateInput(const std::vector<double>& rKeyStops)
{
#ifdef DBG_UTIL
OSL_ENSURE( rKeyStops.size() > 1,
"KeyStopLerp::KeyStopLerp(): key stop vector must have two entries or more" );
// rKeyStops must be sorted in ascending order
for( std::size_t i=1, len=rKeyStops.size(); i<len; ++i )
{
if( rKeyStops[i-1] > rKeyStops[i] )
OSL_FAIL( "KeyStopLerp::KeyStopLerp(): time vector is not sorted in ascending order!" );
}
#else
(void)rKeyStops;
#endif
}
namespace basegfx::utils
{
KeyStopLerp::KeyStopLerp( const std::vector<double>& rKeyStops ) :
maKeyStops(rKeyStops),
mnLastIndex(0)
{
validateInput(maKeyStops);
}
KeyStopLerp::KeyStopLerp( const ::css::uno::Sequence<double>& rKeyStops ) :
maKeyStops(rKeyStops.getLength()),
mnLastIndex(0)
{
std::copy( rKeyStops.begin(), rKeyStops.end(), maKeyStops.begin() );
validateInput(maKeyStops);
}
KeyStopLerp::ResultType KeyStopLerp::lerp(double fAlpha) const
{
// cached value still okay?
if( maKeyStops.at(mnLastIndex) < fAlpha ||
maKeyStops.at(mnLastIndex+1) >= fAlpha )
{
// nope, find new index
mnLastIndex = std::min<std::ptrdiff_t>(
maKeyStops.size()-2,
// range is ensured by max below
std::max<std::ptrdiff_t>(
0,
std::distance( maKeyStops.begin(),
std::lower_bound( maKeyStops.begin(),
maKeyStops.end(),
fAlpha )) - 1 ));
}
// lerp between stop and stop+1
const double fRawLerp=
(fAlpha-maKeyStops.at(mnLastIndex)) /
(maKeyStops.at(mnLastIndex+1) - maKeyStops.at(mnLastIndex));
// clamp to permissible range (input fAlpha might be
// everything)
return ResultType(
mnLastIndex,
std::clamp(fRawLerp,0.0,1.0));
}
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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