color-map.hh

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// Copyright (c) 2015-2018, LAAS-CNRS
// Authors: Joseph Mirabel (joseph.mirabel@laas.fr)
//
// This file is part of gepetto-viewer.
// gepetto-viewer is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation, either version
// 3 of the License, or (at your option) any later version.
//
// gepetto-viewer is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Lesser Public License for more details. You should have
// received a copy of the GNU Lesser General Public License along with
// gepetto-viewer. If not, see <http://www.gnu.org/licenses/>.
 
#ifndef GEPETTO_GUI_COLORMAP_HH
#define GEPETTO_GUI_COLORMAP_HH
 
#include <gepetto/viewer/config-osg.h>
 
#include <QColor>
#include <QDebug>
 
namespace gepetto {
namespace gui {
class ColorMap {
 public:
  static QColor interpolate(std::size_t nbColors, std::size_t index) {
    if (index > nbColors)
      qDebug() << "Nb colors:" << nbColors << "and index" << index;
    return QColor::fromHslF((qreal)index / (qreal)nbColors, 1, 0.5);
  }
 
  ColorMap(std::size_t nbColors) : nbColors_(nbColors), currentIndex_(0) {
    log2up_ = 0;
    mask_ = 0;
    std::size_t val = (nbColors > 0) ? nbColors : 1;
    for (log2up_ = 0; val; ++log2up_, val >>= 1) mask_ = 2 * mask_ + 1;
  }
 
  QColor getColor(std::size_t index) const {
    return ColorMap::interpolate(mask_, remap(index));
  }
 
  void getColor(std::size_t index, osgVector4& color) const {
    QColor c = getColor(index);
    color[0] = (float)c.redF();
    color[1] = (float)c.greenF();
    color[2] = (float)c.blueF();
    color[3] = (float)c.alphaF();
  }
 
  QColor nextColor() {
    QColor color = getColor(currentIndex_);
    currentIndex(currentIndex_ + 1);
    return color;
  }
 
  void currentIndex(std::size_t index) { currentIndex_ = index % nbColors_; }
 
  std::size_t remap(const std::size_t& index) const {
    std::size_t ret = 0;
    std::size_t input = index;
    for (std::size_t i = 0; i < log2up_; ++i) {
      ret <<= 1;
      if (input & 1) ++ret;
      input >>= 1;
    }
    return ret;
  }
 
 private:
  std::size_t nbColors_;
  std::size_t mask_;
  std::size_t log2up_;
  std::size_t currentIndex_;
};
}  // namespace gui
}  // namespace gepetto
 
#endif  // GEPETTO_GUI_COLORMAP_HH