#include "sys-defines.h"
#include "plot.h"
#include "extern.h"

#define ONEBYTE (0xff)

/* forward references */
static int _hpgl_pseudocolor __P((int red, int green, int blue, bool white_allowed));
static void _compute_pseudo_fillcolor __P((int red, int green, int blue, int *pen, double *shading));
static void _set_pen __P((int pen));
static void _set_fill_type __P((int fill_type, double option1));

/* _h_set_hpgl_pencolor() sets the physical pen color to match the pen
   color in our current drawing state.  If the palette contains a matching
   color, the corresponding pen is selected.  Otherwise, the color is
   entered into the palette and the corresponding pen is selected.  If the
   palette cannot be modified, i.e., new pen colors cannot be defined, the
   palette is searched for the closest match, and the corresponding pen is
   selected. */
void
#ifdef _HAVE_PROTOS
_h_set_pen_color(void)
#else
_h_set_pen_color()
#endif
{
  int longred, longgreen, longblue;
  int red, green, blue;
  int i;
  Color color;
  
  color = _plotter->drawstate->fgcolor;
  longred = color.red;
  longgreen = color.green;
  longblue = color.blue;

  /* special case: `monochrome' plotter with only pens #0 and #1,
     interpreted as white and non-white respectively */
  if (_plotter->monochrome)
    {
      i = ((longred == 0xffff && longgreen == 0xffff && longblue == 0xffff) 
	   ? 0 : 1);
      /* select pen */
      _set_pen (i);
      return;
    }

  /* if white pen (pen #0) is a legitimate pen, may be able to use it */
  if (_plotter->hpgl_version == 2 
      && _plotter->opaque_white
      && longred == 0xffff && longgreen == 0xffff && longblue == 0xffff)
    {
      _set_pen (0);
      return;
    }

  /* truncate to 24-bit color */
  red = (longred >> 8) & ONEBYTE;
  green = (longgreen >> 8) & ONEBYTE;
  blue = (longblue >> 8) & ONEBYTE;
  
  /* check whether color is already in the palette */
  for (i = 1; i < MAX_NUM_PENS; i++)
    {
      if (_plotter->pen_defined[i] != 0 /* i.e. defined (hard or soft) */
	  && _plotter->pen_color[i].red == red
	  && _plotter->pen_color[i].green == green
	  && _plotter->pen_color[i].blue == blue)
	/* color is in palette, so just select pen */
	{
	  _set_pen (i);
	  return;
	}
    }      

  /* color not in palette, must do something */
  if (_plotter->palette)
    /* can soft-define pen colors */
    {
      /* assign current `free pen' to be the new color */
      sprintf (_plotter->outbuf.current, "PC%d,%d,%d,%d;", 
	       _plotter->free_pen, red, green, blue);
      _update_buffer (&_plotter->outbuf);
      _plotter->pen_color[_plotter->free_pen].red = red;
      _plotter->pen_color[_plotter->free_pen].green = green;
      _plotter->pen_color[_plotter->free_pen].blue = blue;
      _plotter->pen_defined[_plotter->free_pen] = 1; /* i.e. soft-defined */
      /* select pen */
      _set_pen (_plotter->free_pen);
      /* update free pen, i.e. choose next non-hard-defined pen */
      do
	_plotter->free_pen = (_plotter->free_pen + 1) % MAX_NUM_PENS;
      while (_plotter->pen_defined[_plotter->free_pen] == 2);
      return;
    }
  else
    /* don't have logical pens, i.e. cannot soft-define colors, so select
       closest defined non-white pen in RGB cube, using Euclidean distance
       as our metric */
    {
      _set_pen (_hpgl_pseudocolor (red, green, blue, false));
      return;
    }
}

/* _h_set_fill_color() is similar to _h_set_pen_color: it sets the physical
   pen color and fill type to match the fill color in our current drawing
   state.  For HP7550A plotters and HP-GL/2 devices, that is; we don't
   support filling on HP-GL devices.  There are three possibilities.

   (1) For HP7550A's, we use solid filling (shading is not supported), so
   we determine which defined pen is closest to the fill color in the sense
   of Euclidean distance within the RGB cube.
   
   (2) For HP-GL/2 not supporting soft-definition of pen colors, we use
   shading.  So we must determine which shade of which defined pen is
   closest to the fill color in the sense of Euclidean distance within the
   RGB cube.  `Shades' are desaturations (interpolations between a pen
   color, and white).

   (3) For HP-GL/2 devices supporting soft-definition of pen colors, we use
   solid filling, after defining the fill color as a new pen color if
   necessary. */

void
#ifdef _HAVE_PROTOS
_h_set_fill_color(void)
#else
_h_set_fill_color()
#endif
{
  double d_red, d_green, d_blue, desaturate;
  int longred, longgreen, longblue;
  int red, green, blue;
  int level, i;
  Color color;
  
  level = _plotter->drawstate->fill_level;
  if (level == 0) /* no filling requested */
    return;
  if (_plotter->hpgl_version == 0) /* no filling on generic HP-GL devices */
    return;

  color = _plotter->drawstate->fillcolor;
  d_red = ((double)(color.red))/0xFFFF;
  d_green = ((double)(color.green))/0xFFFF;
  d_blue = ((double)(color.blue))/0xFFFF;

  /* fill_level, if nonzero, specifies the extent to which the nominal fill
     color should be desaturated.  1 means no desaturation, 0xffff means
     complete desaturation (white). */
  desaturate = ((double)level - 1.)/0xFFFE;

  longred = IROUND(0xFFFF * (d_red + desaturate * (1.0 - d_red)));
  longgreen = IROUND(0xFFFF * (d_green + desaturate * (1.0 - d_green)));
  longblue = IROUND(0xFFFF * (d_blue + desaturate * (1.0 - d_blue)));

  /* special case: `monochrome' plotter with only pens #0 and #1,
     interpreted as white and non-white respectively.  If fill color is
     non-white, we use solid #1.  Could do better? */

  if (_plotter->monochrome)
    {
      i = ((longred == 0xffff && longgreen == 0xffff && longblue == 0xffff) 
	   ? 0 : 1);
      /* select pen */
      _set_pen (i);
      /* set fill type to solid, unidirectional */
      _set_fill_type (HPGL_FILL_SOLID_UNI, 0.0);
      return;
    }

  /* if white pen (pen #0) is a legitimate pen, may be able to use it */
  if (_plotter->hpgl_version == 2 
      && _plotter->opaque_white
      && longred == 0xffff && longgreen == 0xffff && longblue == 0xffff)
    {
      /* select pen */
      _set_pen (0);
      /* set fill type to solid, unidirectional */
      _set_fill_type (HPGL_FILL_SOLID_UNI, 0.0);
      return;
    }

  /* truncate to 24-bit color */
  red = (longred >> 8) & ONEBYTE;
  green = (longgreen >> 8) & ONEBYTE;
  blue = (longblue >> 8) & ONEBYTE;
  
  /* check whether color is already in palette */
  for (i = 1; i < MAX_NUM_PENS; i++)
    {
      if (_plotter->pen_defined[i] != 0
	  && _plotter->pen_color[i].red == red
	  && _plotter->pen_color[i].green == green
	  && _plotter->pen_color[i].blue == blue)
	/* color is in palette */
	{
	  /* select pen */
	  _set_pen (i);
	  /* set fill type to solid, unidirectional */
	  _set_fill_type (HPGL_FILL_SOLID_UNI, 0.0);
	  return;
	}
    }      

  /* color not in palette, must do something */
  if (_plotter->hpgl_version == 2 && _plotter->palette)
    /* HP-GL/2, and can soft-define pen colors */
    {
      /* assign current `free pen' to be the new color */
      sprintf (_plotter->outbuf.current, "PC%d,%d,%d,%d;", 
	       _plotter->free_pen, red, green, blue);
      _update_buffer (&_plotter->outbuf);
      _plotter->pen_color[_plotter->free_pen].red = red;
      _plotter->pen_color[_plotter->free_pen].green = green;
      _plotter->pen_color[_plotter->free_pen].blue = blue;
      _plotter->pen_defined[_plotter->free_pen] = 1; /* i.e. soft-defined */
      /* select pen */
      _set_pen (_plotter->free_pen);
      /* update free pen, i.e. choose next non-hard-defined pen */
      do
	_plotter->free_pen = (_plotter->free_pen + 1) % MAX_NUM_PENS;
      while (_plotter->pen_defined[_plotter->free_pen] == 2);
      /* set fill type to solid, unidirectional */
      _set_fill_type (HPGL_FILL_SOLID_UNI, 0.0);
      return;
    }

  else if (_plotter->hpgl_version == 2 && _plotter->palette == false)
    /* HP-GL/2, but can't soft-define pen colors; locate closest point
       in RGB cube that is a desaturated version of one of the defined
       pen colors, and fill by shading at the appropriate level */
    {
      int pen;
      double shading;

      _compute_pseudo_fillcolor (red, green, blue, &pen, &shading);
      _set_pen (pen);
      /* shading level in HP-GL/2 is expressed as a percentage */
      _set_fill_type (HPGL_FILL_SHADING, 100.0 * shading);
      return;
    }

  else
    /* must be a HP7550A (i.e. hpgl_version=1), so select closest defined
       pen in RGB cube, using Euclidean distance as our metric */
    {
      _set_pen (_hpgl_pseudocolor (red, green, blue, true));
      /* set fill type to solid, unidirectional */
      _set_fill_type (HPGL_FILL_SOLID_UNI, 0.0);
      return;
    }
}

static void 
#ifdef _HAVE_PROTOS
_set_pen (int pen)
#else
_set_pen (pen)
     int pen;
#endif
{
  if (pen != _plotter->pen)	/* need to select new pen */
    {
      if (_plotter->pendown)
	{
	  sprintf (_plotter->outbuf.current, "PU;");
	  _update_buffer (&_plotter->outbuf);
	  _plotter->pendown = false;
	}
      sprintf (_plotter->outbuf.current, "SP%d;", pen);
      _update_buffer (&_plotter->outbuf);
      _plotter->pen = pen;
    }
  return;
}

static void 
#ifdef _HAVE_PROTOS
_set_fill_type (int fill_type, double option1)
#else
_set_fill_type (fill_type, option1)
     int fill_type;
     double option1;
#endif
{
  if (fill_type != _plotter->fill_type
      || (fill_type == HPGL_FILL_SHADING 
	  && _plotter->shading_level != option1))
    /* need to emit `FT' instruction */
    {
      switch (fill_type)
	{
	case HPGL_FILL_SOLID_BI:
	case HPGL_FILL_SOLID_UNI:	  
	default:
	  /* options ignored */
	  sprintf (_plotter->outbuf.current, "FT%d;", fill_type);
	  break;
	case HPGL_FILL_SHADING:
	  /* option1 is shading level in percent */
	  sprintf (_plotter->outbuf.current, "FT%d,%.1f;", fill_type, option1);
	  _plotter->shading_level = option1;
	  break;
	/* hatching and cross-hatching, anyone? */
	}
      _update_buffer (&_plotter->outbuf);
      _plotter->fill_type = fill_type;
    }
  return;
}

/* Find closest point within the RGB color cube that is a defined pen
   color, using Euclidean distance as our metric.  We allow white pen 
   (pen #0) to be ruled out, because of our convention that nonwhite pen 
   colors should never be quantized to white.  */
static int
#ifdef _HAVE_PROTOS
_hpgl_pseudocolor (int red, int green, int blue, bool white_allowed)
#else
_hpgl_pseudocolor (red, green, blue, white_allowed)
     int red, green, blue;
     bool white_allowed;
#endif
{
  unsigned long int difference = MAXINT;
  int i;
  int best = 0;

  for (i = (white_allowed ? 0 : 1); i < MAX_NUM_PENS; i++)
    {
      if (_plotter->pen_defined[i] != 0)
	{
	  unsigned long int newdifference;
	  int ored, ogreen, oblue;
	  
	  ored = _plotter->pen_color[i].red;
	  ogreen = _plotter->pen_color[i].green;
	  oblue = _plotter->pen_color[i].blue;
	  newdifference = ((red - ored) * (red - ored)
			   + (green - ogreen) * (green - ogreen)
			   + (blue - oblue) * (blue - oblue));
	  
	  if (newdifference < difference)
	    {
	      difference = newdifference;
	      best = i;
	    }
	}
    }

  return best;
}

/* locate closest point in RGB cube that is a desaturated ("shaded")
   version of one of the defined pen colors, using Euclidean distance as
   our metric */
static void 
#ifdef _HAVE_PROTOS
_compute_pseudo_fillcolor (int red, int green, int blue, int *pen_ptr, double *shading_ptr)
#else
_compute_pseudo_fillcolor (red, green, blue, pen_ptr, shading_ptr)
     int red, green, blue;
     int *pen_ptr;
     double *shading_ptr;
#endif
{
  int best = 0;
  int i;
  double best_shading = 0.0;
  double difference = MAXINT;
  double red_shifted, green_shifted, blue_shifted;
  
  /* shift color vector so that it emanates from `white' */
  red_shifted = (double)(red - 0xff);
  green_shifted = (double)(green - 0xff);
  blue_shifted = (double)(blue - 0xff);

  /* begin with pen #1 */
  for (i = 1; i < MAX_NUM_PENS; i++)
    {
      int ored, ogreen, oblue;
      double ored_shifted, ogreen_shifted, oblue_shifted;
      double red_proj_shifted, green_proj_shifted, blue_proj_shifted;
      double reciprocal_normsquared, dotproduct;
      double newdifference, shading;
      
      /* skip undefined pens */
      if (_plotter->pen_defined[i] == 0)
	continue;
      
      /* shift each pen color vector so that it emanates from `white' */
      ored = _plotter->pen_color[i].red;
      ogreen = _plotter->pen_color[i].green;
      oblue = _plotter->pen_color[i].blue;
      /* if luser specified a white pen, skip it to avoid division by 0 */
      if (ored == 0xff && ogreen == 0xff && oblue == 0xff)
	continue;
      ored_shifted = (double)(ored - 0xff);
      ogreen_shifted = (double)(ogreen - 0xff);
      oblue_shifted = (double)(oblue - 0xff);

      /* project shifted color vector onto shifted pen color vector */
      reciprocal_normsquared = 1.0 / (ored_shifted * ored_shifted
				      + ogreen_shifted * ogreen_shifted
				      + oblue_shifted * oblue_shifted);
      dotproduct = (red_shifted * ored_shifted
		    + green_shifted * ogreen_shifted
		    + blue_shifted * oblue_shifted);
      shading = reciprocal_normsquared * dotproduct;
      
      red_proj_shifted = shading * ored_shifted;
      green_proj_shifted = shading * ogreen_shifted;
      blue_proj_shifted = shading * oblue_shifted;
      
      newdifference = (((red_proj_shifted - red_shifted) 
			* (red_proj_shifted - red_shifted))
		       + ((green_proj_shifted - green_shifted) 
			  * (green_proj_shifted - green_shifted))
		       + ((blue_proj_shifted - blue_shifted) 
			  * (blue_proj_shifted - blue_shifted)));
      
      if (newdifference < difference)
	{
	  difference = newdifference;
	  best = i;
	  best_shading = shading;
	}
    }

  /* compensate for roundoff error */
  if (best_shading <= 0.0)
    best_shading = 0.0;

  *pen_ptr = best;
  *shading_ptr = best_shading;
  return;
}