/******************************************************************************
 *
 *
 *
 *
 * Copyright (C) 1997-2015 by Dimitri van Heesch.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation under the terms of the GNU General Public License is hereby
 * granted. No representations are made about the suitability of this software
 * for any purpose. It is provided "as is" without express or implied warranty.
 * See the GNU General Public License for more details.
 *
 * Documents produced by Doxygen are derivative works derived from the
 * input used in their production; they are not affected by this license.
 *
 */

#include "image.h"
#include <math.h>
#include "lodepng.h"
#include "config.h"

typedef unsigned char  Byte;

/** Helper struct representing a RGBA color */
struct Color
{
  Byte red;
  Byte green;
  Byte blue;
  Byte alpha;
};

const int charSetWidth=80;
const int charHeight=12;
const int numChars=96;

unsigned short charPos[numChars]    =
  {
      0,  5,  8, 13, 20, 27, 38, 47,
     50, 54, 58, 65, 72, 76, 83, 87,
     91, 98,105,112,119,126,133,140,
    147,154,161,164,167,174,181,188,
    195,207,216,224,233,242,250,258,
    267,276,279,286,294,301,312,321,
    331,339,349,357,365,372,380,389,
    400,409,418,427,430,434,437,443,
    450,453,460,467,474,481,488,492,
    499,506,509,512,518,521,530,537,
    544,551,557,562,568,571,578,585,
    594,600,607,613,617,620,624,631
  };

unsigned char charWidth[numChars] =
  {
     5, 3, 5, 7, 7,11, 9, 3,
     4, 4, 7, 7, 4, 7, 4, 4,

     7, 7, 7, 7, 7, 7, 7, 7,
     7, 7, 3, 3, 7, 7, 7, 7,
    12, 9, 8, 9, 9, 8, 8, 9,
     9, 3, 7, 8, 7,11, 9,10,
     8,10, 8, 8, 7, 8, 9,11,
     9, 9, 9, 3, 4, 3, 6, 7,
     3, 7, 7, 7, 7, 7, 4, 7,
     7, 3, 3, 6, 3, 9, 7, 7,
     7, 6, 5, 6, 3, 7, 7, 9,
     6, 7, 6, 4, 3, 4, 7, 5
  };

unsigned char fontRaw[charSetWidth*charHeight] = {
  0x02, 0x50, 0x01, 0x06, 0x20, 0x60, 0xc6, 0x04, 0x00, 0x00, 0x00, 0x27,
  0x04, 0x1c, 0x38, 0x11, 0xf1, 0xc7, 0xc7, 0x0e, 0x00, 0x00, 0x00, 0x03,
  0x81, 0xf0, 0x10, 0x7c, 0x1e, 0x3e, 0x1f, 0x9f, 0x87, 0x88, 0x24, 0x09,
  0x09, 0x02, 0x02, 0x41, 0x0f, 0x0f, 0x83, 0xc3, 0xe1, 0xe7, 0xf4, 0x24,
  0x12, 0x22, 0x41, 0x20, 0x9f, 0xce, 0x30, 0x00, 0x10, 0x04, 0x00, 0x01,
  0x00, 0x30, 0x08, 0x12, 0x41, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40,
  0x00, 0x00, 0x00, 0x00, 0x01, 0xac, 0x00, 0x00, 0x02, 0x51, 0x43, 0x89,
  0x40, 0x90, 0x49, 0x15, 0x00, 0x00, 0x00, 0x28, 0x9c, 0x22, 0x44, 0x31,
  0x02, 0x20, 0x48, 0x91, 0x00, 0x00, 0x00, 0x04, 0x46, 0x08, 0x28, 0x42,
  0x21, 0x21, 0x10, 0x10, 0x08, 0x48, 0x24, 0x09, 0x11, 0x03, 0x06, 0x61,
  0x10, 0x88, 0x44, 0x22, 0x12, 0x10, 0x84, 0x24, 0x12, 0x22, 0x22, 0x20,
  0x80, 0x4a, 0x11, 0x00, 0x20, 0x04, 0x00, 0x01, 0x00, 0x40, 0x08, 0x00,
  0x41, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00,
  0x02, 0x22, 0x00, 0x00, 0x02, 0x51, 0x45, 0x49, 0x40, 0x90, 0x89, 0x0a,
  0x00, 0x00, 0x00, 0x48, 0x84, 0x02, 0x04, 0x51, 0x02, 0x00, 0x88, 0x91,
  0x00, 0x00, 0x00, 0x04, 0x44, 0xd4, 0x28, 0x42, 0x40, 0x20, 0x90, 0x10,
  0x10, 0x08, 0x24, 0x09, 0x21, 0x03, 0x06, 0x51, 0x20, 0x48, 0x48, 0x12,
  0x12, 0x00, 0x84, 0x22, 0x22, 0x22, 0x22, 0x11, 0x00, 0x89, 0x12, 0x80,
  0x31, 0xc5, 0x87, 0x0d, 0x1c, 0xe3, 0x4b, 0x12, 0x49, 0x29, 0x16, 0x1c,
  0x58, 0x69, 0x4c, 0xe8, 0x91, 0x44, 0x61, 0x44, 0xf2, 0x22, 0x00, 0x00,
  0x02, 0x07, 0xe5, 0x06, 0x80, 0x60, 0x10, 0x95, 0x08, 0x00, 0x00, 0x48,
  0x84, 0x04, 0x18, 0x51, 0xe2, 0xc0, 0x87, 0x11, 0x24, 0x18, 0x03, 0x00,
  0x89, 0x24, 0x44, 0x42, 0x40, 0x20, 0x90, 0x10, 0x10, 0x08, 0x24, 0x09,
  0x41, 0x02, 0x8a, 0x51, 0x20, 0x48, 0x48, 0x12, 0x11, 0x80, 0x84, 0x22,
  0x21, 0x24, 0x14, 0x11, 0x01, 0x09, 0x14, 0x40, 0x02, 0x26, 0x48, 0x93,
  0x22, 0x44, 0xcc, 0x92, 0x51, 0x36, 0x99, 0x22, 0x64, 0x99, 0x92, 0x48,
  0x91, 0x44, 0x52, 0x44, 0x12, 0x22, 0x00, 0x00, 0x02, 0x01, 0x43, 0x80,
  0x80, 0xa0, 0x10, 0x84, 0x08, 0x00, 0x00, 0x88, 0x84, 0x08, 0x04, 0x90,
  0x13, 0x21, 0x08, 0x8f, 0x00, 0x61, 0xf0, 0xc0, 0x8a, 0x24, 0x44, 0x7c,
  0x40, 0x20, 0x9f, 0x9f, 0x11, 0xcf, 0xe4, 0x09, 0xc1, 0x02, 0x8a, 0x49,
  0x20, 0x4f, 0x88, 0x13, 0xe0, 0x60, 0x84, 0x22, 0x21, 0x54, 0x08, 0x0a,
  0x02, 0x08, 0x90, 0x00, 0x00, 0x24, 0x48, 0x11, 0x22, 0x44, 0x48, 0x92,
  0x61, 0x24, 0x91, 0x22, 0x44, 0x89, 0x10, 0x48, 0x91, 0x24, 0x8c, 0x44,
  0x22, 0x22, 0x64, 0x00, 0x02, 0x07, 0xe1, 0x41, 0x31, 0x14, 0x10, 0x80,
  0x3e, 0x07, 0xc0, 0x88, 0x84, 0x10, 0x05, 0x10, 0x12, 0x21, 0x08, 0x81,
  0x01, 0x80, 0x00, 0x31, 0x0a, 0x24, 0x7c, 0x42, 0x40, 0x20, 0x90, 0x10,
  0x10, 0x48, 0x24, 0x09, 0x21, 0x02, 0x52, 0x45, 0x20, 0x48, 0x08, 0x92,
  0x20, 0x10, 0x84, 0x21, 0x41, 0x54, 0x14, 0x04, 0x04, 0x08, 0x90, 0x00,
  0x01, 0xe4, 0x48, 0x11, 0x3e, 0x44, 0x48, 0x92, 0x61, 0x24, 0x91, 0x22,
  0x44, 0x89, 0x0c, 0x48, 0x8a, 0x24, 0x8c, 0x48, 0x44, 0x21, 0x98, 0x00,
  0x02, 0x02, 0x85, 0x41, 0x49, 0x08, 0x10, 0x80, 0x08, 0x00, 0x00, 0x88,
  0x84, 0x20, 0x45, 0xf9, 0x12, 0x21, 0x08, 0x81, 0x00, 0x61, 0xf0, 0xc1,
  0x0a, 0x68, 0x82, 0x42, 0x40, 0x20, 0x90, 0x10, 0x10, 0x48, 0x24, 0x89,
  0x11, 0x02, 0x52, 0x45, 0x20, 0x48, 0x08, 0x52, 0x12, 0x10, 0x84, 0x21,
  0x40, 0x88, 0x22, 0x04, 0x08, 0x08, 0x90, 0x00, 0x02, 0x24, 0x48, 0x11,
  0x20, 0x44, 0x48, 0x92, 0x51, 0x24, 0x91, 0x22, 0x44, 0x89, 0x02, 0x48,
  0x8a, 0x2a, 0x92, 0x28, 0x42, 0x22, 0x00, 0x00, 0x00, 0x02, 0x85, 0x41,
  0x49, 0x18, 0x10, 0x80, 0x08, 0x00, 0x01, 0x08, 0x84, 0x20, 0x44, 0x11,
  0x12, 0x22, 0x08, 0x91, 0x00, 0x18, 0x03, 0x00, 0x09, 0xb0, 0x82, 0x42,
  0x21, 0x21, 0x10, 0x10, 0x08, 0xc8, 0x24, 0x89, 0x09, 0x02, 0x22, 0x43,
  0x10, 0x88, 0x04, 0x22, 0x12, 0x10, 0x84, 0x20, 0x80, 0x88, 0x22, 0x04,
  0x10, 0x08, 0x50, 0x00, 0x02, 0x26, 0x48, 0x93, 0x22, 0x44, 0xc8, 0x92,
  0x49, 0x24, 0x91, 0x22, 0x64, 0x99, 0x12, 0x49, 0x84, 0x11, 0x21, 0x28,
  0x82, 0x22, 0x00, 0x00, 0x02, 0x02, 0x83, 0x82, 0x30, 0xe4, 0x10, 0x80,
  0x00, 0x20, 0x05, 0x07, 0x04, 0x3e, 0x38, 0x10, 0xe1, 0xc2, 0x07, 0x0e,
  0x24, 0x00, 0x00, 0x01, 0x04, 0x00, 0x82, 0x7c, 0x1e, 0x3e, 0x1f, 0x90,
  0x07, 0x48, 0x24, 0x71, 0x05, 0xf2, 0x22, 0x41, 0x0f, 0x08, 0x03, 0xd2,
  0x11, 0xe0, 0x83, 0xc0, 0x80, 0x88, 0x41, 0x04, 0x1f, 0xc8, 0x50, 0x00,
  0x01, 0xd5, 0x87, 0x0d, 0x1c, 0x43, 0x48, 0x92, 0x45, 0x24, 0x91, 0x1c,
  0x58, 0x69, 0x0c, 0x66, 0x84, 0x11, 0x21, 0x10, 0xf2, 0x22, 0x00, 0x00,
  0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x09, 0x00, 0x00, 0x20, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
  0x03, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x40, 0x02, 0x00, 0x00, 0x00, 0x00, 0x40, 0x08, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x10, 0x02, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x09, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x08, 0x10, 0x1f, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x04, 0x40, 0x02,
  0x00, 0x00, 0x00, 0x00, 0x40, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20,
  0x02, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x30, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x80, 0x04, 0x00, 0x00, 0x00, 0x00,
  0x40, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x01, 0xac, 0x00, 0x00
};

static Color palette[] =
{
  { 0xff, 0xff, 0xff, 0x00 },
  { 0x00, 0x00, 0x00, 0xff },
  { 0xff, 0xff, 0xc0, 0xff },
  { 0x9f, 0x9f, 0x60, 0xff },
  { 0x90, 0x00, 0x00, 0xff },
  { 0x00, 0x90, 0x00, 0xff },
  { 0x00, 0x00, 0x90, 0xff },
  { 0xc0, 0xc0, 0xc0, 0xff }
};

// for alpha we use x^(1/1.3)
static Color palette2[] =
{
  { 0x00, 0x00, 0x00, 0x00 },
  { 0x00, 0x00, 0x00, 0x2e },
  { 0x00, 0x00, 0x00, 0x48 },
  { 0x00, 0x00, 0x00, 0x5d },
  { 0x00, 0x00, 0x00, 0x6f },
  { 0x00, 0x00, 0x00, 0x80 },
  { 0x00, 0x00, 0x00, 0x8f },
  { 0x00, 0x00, 0x00, 0x9e },
  { 0x00, 0x00, 0x00, 0xac },
  { 0x00, 0x00, 0x00, 0xb9 },
  { 0x00, 0x00, 0x00, 0xc5 },
  { 0x00, 0x00, 0x00, 0xd2 },
  { 0x00, 0x00, 0x00, 0xdd },
  { 0x00, 0x00, 0x00, 0xe9 },
  { 0x00, 0x00, 0x00, 0xf4 },
  { 0x00, 0x00, 0x00, 0xff }
};

static Color palette3[] =
{
  { 0xff, 0xff, 0xff, 0xff },
  { 0xe0, 0xe0, 0xe0, 0xff },
  { 0xd0, 0xd0, 0xd0, 0xff },
  { 0xc0, 0xc0, 0xc0, 0xff },
  { 0xb0, 0xb0, 0xb0, 0xff },
  { 0xa0, 0xa0, 0xa0, 0xff },
  { 0x90, 0x90, 0x90, 0xff },
  { 0x80, 0x80, 0x80, 0xff },
  { 0x70, 0x70, 0x70, 0xff },
  { 0x60, 0x60, 0x60, 0xff },
  { 0x50, 0x50, 0x50, 0xff },
  { 0x40, 0x40, 0x40, 0xff },
  { 0x30, 0x30, 0x30, 0xff },
  { 0x20, 0x20, 0x20, 0xff },
  { 0x10, 0x10, 0x10, 0xff },
  { 0x00, 0x00, 0x00, 0xff }
};


Image::Image(uint w,uint h)
{
  static int hue   = Config_getInt(HTML_COLORSTYLE_HUE);
  static int sat   = Config_getInt(HTML_COLORSTYLE_SAT);
  static int gamma = Config_getInt(HTML_COLORSTYLE_GAMMA);

  double red1,green1,blue1;
  double red2,green2,blue2;

  ColoredImage::hsl2rgb(hue/360.0,                  // hue
                        sat/255.0,                  // saturation
                        pow(235/255.0,gamma/100.0), // luma (gamma corrected)
                        &red1,&green1,&blue1
                       );

  ColoredImage::hsl2rgb(hue/360.0,                  // hue
                        sat/255.0,                  // saturation
                        pow(138/255.0,gamma/100.0), // luma (gamma corrected)
                        &red2,&green2,&blue2
                       );

  palette[2].red   = (int)(red1   * 255.0);
  palette[2].green = (int)(green1 * 255.0);
  palette[2].blue  = (int)(blue1  * 255.0);

  palette[3].red   = (int)(red2   * 255.0);
  palette[3].green = (int)(green2 * 255.0);
  palette[3].blue  = (int)(blue2  * 255.0);

  m_data = new uchar[w*h];
  memset(m_data,0,w*h);
  m_width = w;
  m_height = h;
}

Image::~Image()
{
  delete[] m_data;
}

void Image::setPixel(uint x,uint y,uchar val)
{
  if (x<m_width && y<m_height)
    m_data[y*m_width+x] = val;
}

uchar Image::getPixel(uint x,uint y) const
{
  if (x<m_width && y<m_height)
    return m_data[y*m_width+x];
  else
    return 0;
}

void Image::writeChar(uint x,uint y,char c,uchar fg)
{
  if (c>=' ')
  {
    uint xf,yf,ci=c-' ';
    uint rowOffset=0;
    uint cw = charWidth[ci];
    uint cp = charPos[ci];
    for (yf=0;yf<charHeight;yf++)
    {
      unsigned short bitPattern=0;
      uint bitsLeft=cw;
      uint byteOffset = rowOffset+(cp>>3);
      uint bitOffset  = cp&7;
      // get the bit pattern for row yf of the character from the font data
      while (bitsLeft>0)
      {
        uint bits=8-bitOffset;
        if (bits>bitsLeft) bits=bitsLeft;
        bitPattern<<=bits;
        bitPattern|=((fontRaw[byteOffset]<<bitOffset)&0xff)>>(8-bits);
        bitsLeft-=bits;
        bitOffset=0;
        byteOffset++;
      }
      uint mask=1<<(cw-1);
      // draw character row yf
      for (xf=0;xf<cw;xf++)
      {
        setPixel(x+xf,y+yf,(bitPattern&mask) ? fg : getPixel(x+xf,y+yf));
        mask>>=1;
      }
      rowOffset+=charSetWidth;
    }
  }
}

void Image::writeString(uint x,uint y,const char *s,uchar fg)
{
  if (s)
  {
    char c;
    while ((c=*s++))
    {
      writeChar(x,y,c,fg);
      x+=charWidth[c-' '];
    }
  }
}

uint Image::stringLength(const char *s)
{
  uint w=0;
  if (s)
  {
    char c;
    while ((c=*s++)) w+=charWidth[c-' '];
  }
  return w;
}

void Image::drawHorzLine(uint y,uint xs,uint xe,uchar colIndex,uint mask)
{
  uint x,i=0,j=0;
  for (x=xs;x<=xe;x++,j++)
  {
    if (j&1) i++;
    if (mask&(1<<(i&0x1f))) setPixel(x,y,colIndex);
  }
}

void Image::drawHorzArrow(uint y,uint xs,uint xe,uchar colIndex,uint mask)
{
  drawHorzLine(y,xs,xe,colIndex,mask);
  uint i;
  for (i=0;i<6;i++)
  {
    uint h=i>>1;
    drawVertLine(xe-i,y-h,y+h,colIndex,0xffffffff);
  }
}

void Image::drawVertLine(uint x,uint ys,uint ye,uchar colIndex,uint mask)
{
  uint y,i=0;
  for (y=ys;y<=ye;y++,i++)
  {
    if (mask&(1<<(i&0x1f))) setPixel(x,y,colIndex);
  }
}

void Image::drawVertArrow(uint x,uint ys,uint ye,uchar colIndex,uint mask)
{
  drawVertLine(x,ys,ye,colIndex,mask);
  uint i;
  for (i=0;i<6;i++)
  {
    uint h=i>>1;
    drawHorzLine(ys+i,x-h,x+h,colIndex,0xffffffff);
  }
}

void Image::drawRect(uint x,uint y,uint w,uint h,uchar colIndex,uint mask)
{
  drawHorzLine(y,x,x+w-1,colIndex,mask);
  drawHorzLine(y+h-1,x,x+w-1,colIndex,mask);
  drawVertLine(x,y,y+h-1,colIndex,mask);
  drawVertLine(x+w-1,y,y+h-1,colIndex,mask);
}

void Image::fillRect(uint x,uint y,uint width,uint height,uchar colIndex,uint mask)
{
  uint xp,yp,xi,yi;
  for (yp=y,yi=0;yp<y+height;yp++,yi++)
    for (xp=x,xi=0;xp<x+width;xp++,xi++)
      if (mask&(1<<((xi+yi)&0x1f)))
        setPixel(xp,yp,colIndex);
}

bool Image::save(const char *fileName,int mode)
{
  static bool useTransparency = Config_getBool(FORMULA_TRANSPARENT);
  uchar* buffer;
  size_t bufferSize;
  LodePNG_Encoder encoder;
  LodePNG_Encoder_init(&encoder);
  uint numCols = mode==0 ? 8 : 16;
  Color *pPal = mode==0         ? palette  :
                useTransparency ? palette2 :
                                  palette3 ;
  uint i;
  for (i=0;i<numCols;i++,pPal++)
  {
    LodePNG_InfoColor_addPalette(&encoder.infoPng.color,
                                 pPal->red,pPal->green,pPal->blue,pPal->alpha);
  }
  encoder.infoPng.color.colorType = 3;
  encoder.infoRaw.color.colorType = 3;
  LodePNG_encode(&encoder, &buffer, &bufferSize, m_data, m_width, m_height);
  LodePNG_saveFile(buffer, bufferSize, fileName);
  free(buffer);
  LodePNG_Encoder_cleanup(&encoder);
  return TRUE;
}

//----------------------------------------------------------------

void ColoredImage::hsl2rgb(double h,double s,double l,
                         double *pRed,double *pGreen,double *pBlue)
{
  double v;
  double r,g,b;

  r = l;   // default to gray
  g = l;
  b = l;
  v = (l <= 0.5) ? (l * (1.0 + s)) : (l + s - l * s);
  if (v > 0)
  {
    double m;
    double sv;
    int sextant;
    double fract, vsf, mid1, mid2;

    m       = l + l - v;
    sv      = (v - m ) / v;
    h      *= 6.0;
    sextant = (int)h;
    fract   = h - sextant;
    vsf     = v * sv * fract;
    mid1    = m + vsf;
    mid2    = v - vsf;
    switch (sextant)
    {
      case 0:
        r = v;
        g = mid1;
        b = m;
        break;
      case 1:
        r = mid2;
        g = v;
        b = m;
        break;
      case 2:
        r = m;
        g = v;
        b = mid1;
        break;
      case 3:
        r = m;
        g = mid2;
        b = v;
        break;
      case 4:
        r = mid1;
        g = m;
        b = v;
        break;
      case 5:
        r = v;
        g = m;
        b = mid2;
        break;
    }
  }
  *pRed   = r;
  *pGreen = g;
  *pBlue  = b;
}

ColoredImage::ColoredImage(uint width,uint height,
           const uchar *greyLevels,const uchar *alphaLevels,
           int saturation,int hue,int gamma)
{
  m_hasAlpha = alphaLevels!=0;
  m_width    = width;
  m_height   = height;
  m_data     = (uchar*)malloc(width*height*4);
  uint i;
  for (i=0;i<width*height;i++)
  {
    uchar r,g,b,a;
    double red,green,blue;
    hsl2rgb(hue/360.0,                            // hue
            saturation/255.0,                     // saturation
            pow(greyLevels[i]/255.0,gamma/100.0), // luma (gamma corrected)
            &red,&green,&blue);
    r = (int)(red  *255.0);
    g = (int)(green*255.0);
    b = (int)(blue *255.0);
    a = alphaLevels ? alphaLevels[i] : 255;
    m_data[i*4+0]=r;
    m_data[i*4+1]=g;
    m_data[i*4+2]=b;
    m_data[i*4+3]=a;
  }
}

ColoredImage::~ColoredImage()
{
  free(m_data);
}

bool ColoredImage::save(const char *fileName)
{
  uchar *buffer;
  size_t bufferSize;
  LodePNG_Encoder encoder;
  LodePNG_Encoder_init(&encoder);
  encoder.infoPng.color.colorType = m_hasAlpha ? 6 : 2; // 2=RGB 24 bit, 6=RGBA 32 bit
  encoder.infoRaw.color.colorType = 6; // 6=RGBA 32 bit
  LodePNG_encode(&encoder, &buffer, &bufferSize, m_data, m_width, m_height);
  LodePNG_saveFile(buffer, bufferSize, fileName);
  LodePNG_Encoder_cleanup(&encoder);
  free(buffer);
  return TRUE;
}