ColorCoder.cc

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//=============================================================================
//
//  CLASS ColorCoder
//
//=============================================================================

//== INCLUDES =================================================================

#include <ACG/Utils/ColorCoder.hh>

//== NAMESPACES ===============================================================

namespace ACG {

//== CLASS DEFINITION =========================================================


ColorCoder::ColorCoder(float _min, float _max, bool _signed)
{
  set_range(_min, _max, _signed);
}

void ColorCoder::set_range(float _min, float _max, bool _signed)
{
  if (_min == _max) {
    val0_ = val1_ = val2_ = val3_ = val4_ = _min;
  } else {
    if (_min > _max)
      std::swap(_min, _max);
    val0_ = _min;
    val4_ = _max;
    val2_ = 0.5 * (val0_ + val4_);
    val1_ = 0.5 * (val0_ + val2_);
    val3_ = 0.5 * (val2_ + val4_);
  }
  signed_mode_ = _signed;
}

ACG::Vec4uc ColorCoder::color4(float _v) const
{
  return signed_mode_ ? color_signed(_v) : color_unsigned(_v);
}

ACG::Vec4f ColorCoder::color_float4(float _v) const
{
  ACG::Vec4uc c = color4(_v);
  return (ACG::Vec4f(c[0], c[1], c[2], c[3]) / 255.f);
}

float ColorCoder::min() const
{
  return val0_;
}
float ColorCoder::max() const
{
  return val4_;
}

ACG::Vec4uc ColorCoder::color_unsigned(float _v) const
{
  if (val4_ <= val0_)
    return ACG::Vec4uc(0, 0, 255, 255);

  unsigned char u;

  if (_v < val0_)
    return ACG::Vec4uc(0, 0, 255, 255);
  if (_v > val4_)
    return ACG::Vec4uc(255, 0, 0, 255);

  if (_v <= val2_) {
    // [v0, v1]
    if (_v <= val1_) {
      u = (unsigned char) (255.0 * (_v - val0_) / (val1_ - val0_));
      return ACG::Vec4uc(0, u, 255, 255);
    }
    // ]v1, v2]
    else {
      u = (unsigned char) (255.0 * (_v - val1_) / (val2_ - val1_));
      return ACG::Vec4uc(0, 255, 255 - u, 255);
    }
  } else {
    // ]v2, v3]
    if (_v <= val3_) {
      u = (unsigned char) (255.0 * (_v - val2_) / (val3_ - val2_));
      return ACG::Vec4uc(u, 255, 0, 255);
    }
    // ]v3, v4]
    else {
      u = (unsigned char) (255.0 * (_v - val3_) / (val4_ - val3_));
      return ACG::Vec4uc(255, 255 - u, 0, 255);
    }
  }
}

ACG::Vec4uc ColorCoder::color_signed(float _v) const
{
  if (val4_ <= val0_)
    return ACG::Vec4uc(0, 255, 0, 255);

  unsigned char r, g, b;

  if (_v < val0_)
    _v = val0_;
  else if (_v > val4_)
    _v = val4_;

  if (_v < 0.0) {
    r = val0_ ? (unsigned char) (255.0 * _v / val0_) : 0;
    b = 0;
  } else {
    r = 0;
    b = val4_ ? (unsigned char) (255.0 * _v / val4_) : 0;
  }
  g = 255 - r - b;

  return ACG::Vec4uc(r, g, b, 255);
}


//=============================================================================
}// namespace ACG
//=============================================================================
//=============================================================================