/*
 * file: hot/hot.c
 *
 * $Id: hot.c,v 1.4 1997/04/14 17:04:48 erich Exp $
 */

/*
 * hot.c - Scan an image for pixels with RGB values that will give
 *	"unsafe" values of chrominance signal or composite signal
 *	amplitude when encoded into an NTSC or PAL colour signal.
 *	(This happens for certain high-intensity high-saturation colours
 *	that are rare in real scenes, but can easily be present
 *	in synthetic images.)
 *
 * 	Such pixels can be flagged so the user may then choose other
 *	colours.  Or, the offending pixels can be made "safe"
 *	in a manner that preserves hue.
 *
 *	There are two reasonable ways to make a pixel "safe":
 *	We can reduce its intensity (luminance) while leaving
 *	hue and saturation the same.  Or, we can reduce saturation
 *	while leaving hue and luminance the same.  A #define selects
 *	which strategy to use.
 *
 * Note to the user: You must add your own read_pixel() and write_pixel()
 *	routines.  You may have to modify pix_decode() and pix_encode().
 *	MAXPIX, WID, and HGT are likely to need modification.
 */

/*
 * Originally written as "ikNTSC.c" by Alan Wm Paeth,
 *	University of Waterloo, August, 1985
 * Updated by Dave Martindale, Imax Systems Corp., December 1990
 */

/*
 * Compile time options:
 *
 *
 * CHROMA_LIM is the limit (in IRE units) of the overall
 *	chrominance amplitude; it should be 50 or perhaps
 *	very slightly higher.
 * 
 * COMPOS_LIM is the maximum amplitude (in IRE units) allowed for
 *	the composite signal.  A value of 100 is the maximum
 *	monochrome white, and is always safe.  120 is the absolute
 *	limit for NTSC broadcasting, since the transmitter's carrier
 *	goes to zero with 120 IRE input signal.  Generally, 110
 *	is a good compromise - it allows somewhat brighter colours
 *	than 100, while staying safely away from the hard limit.
 */

/*
 * run-time options:
 *
 * Define either NTSC or PAL as 1 to select the colour system.
 * Define the other one as zero, or leave it undefined.
 *
 * Define FLAG_HOT as 1 if you want "hot" pixels set to black
 *	to identify them.  Otherwise they will be made safe.
 *
 * Define REDUCE_SAT as 1 if you want hot pixels to be repaired by
 *	reducing their saturation.  By default, luminance is reduced.
 *
 */
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <libgimp/gimp.h>
#include <glib/glib.h>
#include <gtk/gtk.h>
#include <gdk/gdk.h>
#include "megawidget.h"

struct Grgb {
  guint8 red;
  guint8 green;
  guint8 blue;
};

struct GRegion {
  gint32 x;
  gint32 y;
  gint32 width;
  gint32 height;
};

struct piArgs {
  gint32 image;
  gint32 drawable;
  gint32 mode;
  gint32 action;
  gint32 new_layerp;
};

typedef enum {
  act_lredux = 0,
  act_sredux = 1,
  act_flag = 2,
} hotAction;

typedef enum {
  mode_ntsc = 0,
  mode_pal = 1,
} hotModes;

#define	CHROMA_LIM      50.0		/* chroma amplitude limit */
#define	COMPOS_LIM      110.0		/* max IRE amplitude */

/*
 * RGB to YIQ encoding matrix.
 */

struct {
  double pedestal;
  double gamma;
  double code[3][3];
} mode[2] = {
  {
     7.5,
     2.2,
     {
        { 0.2989,  0.5866,  0.1144 },
        { 0.5959, -0.2741, -0.3218 },
        { 0.2113, -0.5227,  0.3113 }
     }
  },
  {
     0.0,
     2.8,
     {
        { 0.2989,  0.5866,  0.1144 },
        { -0.1473, -0.2891,  0.4364 },
        { 0.6149, -0.5145, -0.1004 }
     }
  }
};


#define SCALE	8192            /* scale factor: do floats with int math */
#define MAXPIX	 255            /* white value */

int	tab[3][3][MAXPIX+1];   /* multiply lookup table */
double	chroma_lim;            /* chroma limit */
double	compos_lim;            /* composite amplitude limit */
long	ichroma_lim2;          /* chroma limit squared (scaled integer) */
int	icompos_lim;           /* composite amplitude limit (scaled integer) */

static void query(void);
static void run(char *name, int nparam, GParam *param,
                int *nretvals, GParam **retvals);

gint pluginCore(struct piArgs *argp);
gint pluginCoreIA(struct piArgs *argp);
static gint hotp(register guint8 r, register guint8 g, register guint8 b);
static void build_tab(int m);

/*
 * gc: apply the gamma correction specified for this video standard.
 * inv_gc: inverse function of gc.
 *
 * These are generally just a call to pow(), but be careful!
 * Future standards may use more complex functions.
 * (e.g. SMPTE 240M's "electro-optic transfer characteristic").
 */
#define gc(x,m) pow(x, 1.0 / mode[m].gamma)
#define inv_gc(x,m) pow(x, mode[m].gamma)

/*
 * pix_decode: decode an integer pixel value into a floating-point
 *	intensity in the range [0, 1].
 *
 * pix_encode: encode a floating-point intensity into an integer
 *	pixel value.
 *
 * The code given here assumes simple linear encoding; you must change
 * these routines if you use a different pixel encoding technique.
 */
#define pix_decode(v)  ((double)v / (double)MAXPIX)
#define pix_encode(v)  ((int)(v * (double)MAXPIX + 0.5))

GPlugInInfo PLUG_IN_INFO = {
  NULL, /* init */
  NULL, /* quit */
  query, /* query */
  run, /* run */
};

MAIN();

static void
query(void){
  static GParamDef args[] = {
    { PARAM_INT32, "run_mode", "Interactive, non-interactive" },
    { PARAM_IMAGE, "image", "The Image" },
    { PARAM_DRAWABLE, "drawable", "The Drawable" },
    { PARAM_INT32, "mode", "Mode -- NTSC/PAL" },
    { PARAM_INT32, "action", "The action to perform" },
    { PARAM_INT32, "new_layerp", "Create a new layer iff True" },
  };
  static int nargs = 3;

  static GParamDef *rets = NULL;
  static int nrets = 0;

  gimp_install_procedure("hot",
                         "Look for hot NTSC or PAL pixels ",
                         "hot scans an image for pixels that will give
unsave values of chrominance or composite
signale amplitude when encoded into an NTSC
or PAL signal.  Three actions can be performed on these ``hot''
pixels. (0) reduce luminance, (1) reduce saturation, or (2) Blacken.",
                         "Eric L. Hernes, Alan Wm Paeth",
                         "Eric L. Hernes",
                         "1997",
                         "<Image>/Filters/Image/Hot",
                         "RGB",
                         PROC_PLUG_IN,
                         nargs, nrets,
                         args, rets);
}

static void
run(char *name, int nparam, GParam *param,
    int *nretvals, GParam **retvals){
  static GParam rvals[1];

  struct piArgs args;

  *nretvals = 1;
  *retvals = rvals;

  bzero(&args, sizeof(struct piArgs));
  args.mode=-1;

  gimp_get_data("plug_in_hot", &args);

  rvals[0].type = PARAM_STATUS;
  rvals[0].data.d_status = STATUS_SUCCESS;
  switch (param[0].data.d_int32) {
    case RUN_INTERACTIVE:
      /* XXX: add code here for interactive running */
      args.image = param[1].data.d_image;
      args.drawable = param[2].data.d_drawable;
      if(args.mode == -1) {
         args.mode = mode_ntsc;
         args.action =   act_lredux;
         args.new_layerp =   1;
      }
      
      if (pluginCoreIA(&args)==-1) {
        rvals[0].data.d_status = STATUS_EXECUTION_ERROR;
      }
      gimp_set_data("plug_in_hot", &args, sizeof(struct piArgs));
      
    break;

    case RUN_NONINTERACTIVE:
      /* XXX: add code here for non-interactive running */
      if (nparam != 3) {
        rvals[0].data.d_status = STATUS_CALLING_ERROR;
        break;
      }
      args.image = param[1].data.d_image;
      args.drawable = param[2].data.d_drawable;
      args.mode = param[3].data.d_drawable;
      args.action = param[4].data.d_drawable;

      if (pluginCore(&args)==-1) {
        rvals[0].data.d_status = STATUS_EXECUTION_ERROR;
        break;
      }
    break;

    case RUN_WITH_LAST_VALS:
      /* XXX: add code here for last-values running */
      if (pluginCore(&args)==-1) {
        rvals[0].data.d_status = STATUS_EXECUTION_ERROR;
      }
    break;

  }

}

gint
pluginCore(struct piArgs *argp) {
  GDrawable *drw, *ndrw=NULL;
  GPixelRgn srcPr, dstPr;
  gint retval = 0;
  gint nl=0;
  gint y, x, i;
  gint Y, I, Q;
  guint width, height, Bpp;
  gint prog_interval;
  guchar *src, *s, *dst, *d;
  guchar r, prev_r=0, new_r=0;
  guchar g, prev_g=0, new_g=0;
  guchar b, prev_b=0, new_b=0;
  gdouble fy, fc, t, scale;
  gdouble pr, pg, pb;
  gdouble py;
  
  drw = gimp_drawable_get(argp->drawable);

  width = drw->width;
  height = drw->height;
  Bpp = drw->bpp;
  if(argp->new_layerp) {
    char name[40];
    char *mode_names[] = {
      "ntsc",
      "pal",
    };
    char *action_names[] = {
      "lum redux",
      "sat redux",
      "flag",
    };
      
    sprintf(name, "hot mask (%s, %s)", mode_names[argp->mode],
            action_names[argp->action]);
	     
    nl=gimp_layer_new(argp->image, name, width, height,
                      RGBA_IMAGE, (gdouble)100, NORMAL_MODE);
    ndrw = gimp_drawable_get(nl);
    gimp_drawable_fill(nl, TRANS_IMAGE_FILL);
    gimp_image_add_layer(argp->image, nl, 0);
  }

  src = (guchar*)malloc(width*height*Bpp);
  dst = (guchar*)malloc(width*height*4);
  gimp_pixel_rgn_init (&srcPr, drw, 0, 0, width, height, FALSE, FALSE);
  if (argp->new_layerp) {
    gimp_pixel_rgn_init (&dstPr, ndrw, 0, 0, width, height, FALSE, FALSE);
  } else {
    gimp_pixel_rgn_init (&dstPr, drw, 0, 0, width, height, TRUE, TRUE);
  }

  gimp_pixel_rgn_get_rect(&srcPr, src, 0, 0, width, height);

  s=src;
  d=dst;

  build_tab(argp->mode);

  gimp_progress_init("Hot");
  prog_interval=height/10;
  
  for(y=0;y<height;y++) {
    if (y % prog_interval == 0) gimp_progress_update((double)y/(double)height);
    for(x=0;x<width;x++) {
      if (hotp(r=*(s+0),g=*(s+1),b=*(s+2))) {
         if (argp->action == act_flag) {
            for(i=0;i<3;i++)
               *d++=0;
            s+=3;
            if (Bpp==4) *d++=*s++; else if (argp->new_layerp) *d++=255;
         } else {
                /*
                 * Optimization: cache the last-computed hot pixel.
                 */
            if (r == prev_r && g == prev_g && b == prev_b) {
               *d++ = new_r;
               *d++ = new_g;
               *d++ = new_b;
               s+=3;
               if (Bpp==4) *d++=*s++; else if (argp->new_layerp) *d++=255;
            } else {
               
               Y = tab[0][0][r] + tab[0][1][g] + tab[0][2][b];
               I = tab[1][0][r] + tab[1][1][g] + tab[1][2][b];
               Q = tab[2][0][r] + tab[2][1][g] + tab[2][2][b];
               
               prev_r = r;
               prev_g = g;
               prev_b = b;
                   /*
                    * Get Y and chroma amplitudes in floating point.
                    *
                    * If your C library doesn't have hypot(), just use
                    * hypot(a,b) = sqrt(a*a, b*b);
                    *
                    * Then extract linear (un-gamma-corrected)
                    * floating-point pixel RGB values.
                    */
               fy = (double)Y / (double)SCALE;
               fc = hypot((double)I / (double)SCALE,
                          (double)Q / (double)SCALE);
               
               pr = (double)pix_decode(r);
               pg = (double)pix_decode(g);
               pb = (double)pix_decode(b);
               
                   /*
                    * Reducing overall pixel intensity by scaling R,
                    * G, and B reduces Y, I, and Q by the same factor.
                    * This changes luminance but not saturation, since
                    * saturation is determined by the chroma/luminance
                    * ratio.
                    *
                    * On the other hand, by linearly interpolating
                    * between the original pixel value and a grey
                    * pixel with the same luminance (R=G=B=Y), we
                    * change saturation without affecting luminance.
                    */
               if(argp->action == act_lredux) {
                      /*
                       * Calculate a scale factor that will bring the pixel
                       * within both chroma and composite limits, if we scale
                       * luminance and chroma simultaneously.
                       *
                       * The calculated chrominance reduction applies
                       * to the gamma-corrected RGB values that are
                       * the input to the RGB-to-YIQ operation.
                       * Multiplying the original un-gamma-corrected
                       * pixel values by the scaling factor raised to
                       * the "gamma" power is equivalent, and avoids
                       * calling gc() and inv_gc() three times each.  */
                  scale = chroma_lim / fc;
                  t = compos_lim / (fy + fc);
                  if (t < scale)
                     scale = t;
                  scale = pow(scale, mode[argp->mode].gamma);
                  
                  
                  r = (guint8)pix_encode(scale * pr);
                  g = (guint8)pix_encode(scale * pg);
                  b = (guint8)pix_encode(scale * pb);
                  
               } else { /* act_sredux hopefully */
                      /*
                       * Calculate a scale factor that will bring the
                       * pixel within both chroma and composite
                       * limits, if we scale chroma while leaving
                       * luminance unchanged.
                       *
                       * We have to interpolate gamma-corrected RGB
                       * values, so we must convert from linear to
                       * gamma-corrected before interpolation and then
                       * back to linear afterwards.
                       */
                  scale = chroma_lim / fc;
                  t = (compos_lim - fy) / fc;
                  if (t < scale)
                     scale = t;
                  
                  pr = gc(pr,argp->mode);
                  pg = gc(pg,argp->mode);
                  pb = gc(pb,argp->mode);
                  py = pr * mode[argp->mode].code[0][0] + pg * 
                     mode[argp->mode].code[0][1] + pb *
                     mode[argp->mode].code[0][2];
                  r = pix_encode(inv_gc(py + scale * (pr - py), argp->mode));
                  g = pix_encode(inv_gc(py + scale * (pg - py), argp->mode));
                  b = pix_encode(inv_gc(py + scale * (pb - py), argp->mode));
               }
               *d++ = new_r = r;
               *d++ = new_g = g;
               *d++ = new_b = b;
               s+=3;
               if (Bpp==4) *d++=*s++; else if (argp->new_layerp) *d++=255;
            }
         }
      } else {
         if (!argp->new_layerp) {
            for(i=0;i<Bpp;i++)
               *d++=*s++;
         } else {
            s+=Bpp;
            d+=4;
         }
      }
    }
  }
  gimp_pixel_rgn_set_rect(&dstPr, dst, 0, 0, width, height);
  
  free(src);
  free(dst);
  
  if(argp->new_layerp) {
     gimp_drawable_flush(ndrw);
     gimp_drawable_update(nl, 0, 0, width, height);
  } else {
     gimp_drawable_flush(drw);
     gimp_drawable_merge_shadow (drw->id, TRUE);
     gimp_drawable_update(drw->id, 0, 0, width, height);
  }
  
  gimp_displays_flush();
  
  return retval;
}

gint
pluginCoreIA(struct piArgs *argp) {
  GtkWidget *dlg;
  GtkWidget *hbox;
  GtkWidget *vbox;
  gint runp;
  struct mwRadioGroup modes[] = {
     { "NTSC", 1 },
     { "PAL", 0 },
     { NULL, 0 }
  };
  struct mwRadioGroup actions[] = {
     { "Reduce Luminance", 0 },
     { "Reduce Saturation", 0 },
     { "Blacken (flag)", 0 },
     { NULL, 0}
  };

  actions[argp->action].var = 1;

  dlg = mw_app_new("plug_in_hot", "Hot", &runp);
  hbox = gtk_hbox_new(FALSE, 5);
  gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dlg)->vbox), hbox, TRUE, TRUE, 0);
  gtk_widget_show(hbox);

  vbox = gtk_vbox_new(FALSE, 5);
  gtk_box_pack_start(GTK_BOX(hbox), vbox, TRUE, TRUE, 0);
  gtk_widget_show(vbox);

  mw_toggle_button_new(vbox, NULL, "Create New Layer", &argp->new_layerp);
  mw_radio_group_new(vbox, "Mode", modes);

  mw_radio_group_new(hbox, "Action", actions);

  gtk_widget_show(dlg);
  gtk_main();
  gdk_flush();

  argp->mode = mw_radio_result(modes);
  argp->action = mw_radio_result(actions);
  
  if (runp) {
     return pluginCore(argp);
  } else {
     return -1;
  }
}

/*
 * build_tab: Build multiply lookup table.
 *
 * For each possible pixel value, decode value into floating-point
 * intensity.  Then do gamma correction required by the video
 * standard.  Scale the result by our fixed-point scale factor.
 * Then calculate 9 lookup table entries for this pixel value.
 *
 * We also calculate floating-point and scaled integer versions
 * of our limits here.  This prevents evaluating expressions every pixel
 * when the compiler is too stupid to evaluate constant-valued
 * floating-point expressions at compile time.
 *
 * For convenience, the limits are #defined using IRE units.
 * We must convert them here into the units in which YIQ
 * are measured.  The conversion from IRE to internal units
 * depends on the pedestal level in use, since as Y goes from
 * 0 to 1, the signal goes from the pedestal level to 100 IRE.
 * Chroma is always scaled to remain consistent with Y.
 */
void
build_tab(int m) {
  register double f;
  register int pv;

  for (pv = 0; pv <= MAXPIX; pv++) {
    f = (double)SCALE * (double)gc((double)pix_decode(pv),m);
    tab[0][0][pv] = (int)(f * mode[m].code[0][0] + 0.5);
    tab[0][1][pv] = (int)(f * mode[m].code[0][1] + 0.5);
    tab[0][2][pv] = (int)(f * mode[m].code[0][2] + 0.5);
    tab[1][0][pv] = (int)(f * mode[m].code[1][0] + 0.5);
    tab[1][1][pv] = (int)(f * mode[m].code[1][1] + 0.5);
    tab[1][2][pv] = (int)(f * mode[m].code[1][2] + 0.5);
    tab[2][0][pv] = (int)(f * mode[m].code[2][0] + 0.5);
    tab[2][1][pv] = (int)(f * mode[m].code[2][1] + 0.5);
    tab[2][2][pv] = (int)(f * mode[m].code[2][2] + 0.5);
  }

  chroma_lim = (double)CHROMA_LIM / (100.0 - mode[m].pedestal);
  compos_lim = ((double)COMPOS_LIM - mode[m].pedestal) /
    (100.0 - mode[m].pedestal);

  ichroma_lim2 = (int)(chroma_lim * SCALE + 0.5);
  ichroma_lim2 *= ichroma_lim2;
  icompos_lim = (int)(compos_lim * SCALE + 0.5);
}

int
hotp(register guint8 r, register guint8 g, register guint8 b) {
  register int	y, i, q;
  register long	y2, c2;

  /*  fprintf(stderr, "\tr: %d, g: %d, b: %d\n", r, g, b);*/
  
  /*
   * Pixel decoding, gamma correction, and matrix multiplication
   * all done by lookup table.
   *
   * "i" and "q" are the two chrominance components;
   * they are I and Q for NTSC.
   * For PAL, "i" is U (scaled B-Y) and "q" is V (scaled R-Y).
   * Since we only care about the length of the chroma vector,
   * not its angle, we don't care which is which.
   */
  y = tab[0][0][r] + tab[0][1][g] + tab[0][2][b];
  i = tab[1][0][r] + tab[1][1][g] + tab[1][2][b];
  q = tab[2][0][r] + tab[2][1][g] + tab[2][2][b];

  /*
   * Check to see if the chrominance vector is too long or the
   * composite waveform amplitude is too large.
   *
   * Chrominance is too large if
   *
   *	sqrt(i^2, q^2)  >  chroma_lim.
   *
   * The composite signal amplitude is too large if
   *
   *	y + sqrt(i^2, q^2)  >  compos_lim.
   *
   * We avoid doing the sqrt by checking
   *
   *	i^2 + q^2  >  chroma_lim^2
   * and
   *	y + sqrt(i^2 + q^2)  >  compos_lim
   *	sqrt(i^2 + q^2)  >  compos_lim - y
   *	i^2 + q^2  >  (compos_lim - y)^2
   *
   */

  c2 = (long)i * i + (long)q * q;
  y2 = (long)icompos_lim - y;
  y2 *= y2;
  /*  fprintf(stderr, "hotp: c2: %d; ichroma_lim2: %d; y2: %d; ",
	  c2, ichroma_lim2, y2);*/
  
  if (c2 <= ichroma_lim2 && c2 <= y2) {	/* no problems */
    /*    fprintf(stderr, "nope\n");*/
    return 0;
  }

  /*  fprintf(stderr, "yup\n");*/
  return 1;
}

/*
 * Local Variables:
 * mode: C
 * End:
 */

/* end of file: hot/hot.c */
