/*
 * This is a plug-in for GIMP.
 *
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 * Copyright (C) 1996 Torsten Martinsen
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"

#include <string.h>

#include <libgimp/gimp.h>
#include <libgimp/gimpui.h>

#include "libgimp/stdplugins-intl.h"


#define PLUG_IN_PROC   "plug-in-oilify"
#define PLUG_IN_BINARY "oilify"

#define SCALE_WIDTH    125
#define HISTSIZE       256

#define MODE_RGB         0
#define MODE_INTEN       1


typedef struct
{
  gdouble  mask_size;
  gint     mode;
  gboolean preview;
} OilifyVals;


/* Declare local functions.
 */
static void      query  (void);
static void      run    (const gchar      *name,
                         gint              nparams,
                         const GimpParam  *param,
                         gint             *nreturn_vals,
                         GimpParam       **return_vals);

static void      oilify             (GimpDrawable *drawable,
                                     GimpPreview  *preview);

static gboolean  oilify_dialog      (GimpDrawable *drawable);


const GimpPlugInInfo PLUG_IN_INFO =
{
  NULL,  /* init_proc  */
  NULL,  /* quit_proc  */
  query, /* query_proc */
  run,   /* run_proc   */
};

static OilifyVals ovals =
{
  7.0,        /* mask size */
  MODE_INTEN, /* mode      */
  TRUE        /* preview   */
};


MAIN ()

static void
query (void)
{
  static const GimpParamDef args[] =
  {
    { GIMP_PDB_INT32,    "run-mode",  "Interactive, non-interactive"       },
    { GIMP_PDB_IMAGE,    "image",     "Input image (unused)"               },
    { GIMP_PDB_DRAWABLE, "drawable",  "Input drawable"                     },
    { GIMP_PDB_INT32,    "mask-size", "Oil paint mask size"                },
    { GIMP_PDB_INT32,    "mode",      "Algorithm {RGB (0), INTENSITY (1)}" }
  };

  gimp_install_procedure (PLUG_IN_PROC,
                          N_("Smear colors to simulate an oil painting"),
                          "This function performs the well-known oil-paint "
                          "effect on the specified drawable.  The size of the "
                          "input mask is specified by 'mask_size'.",
                          "Torsten Martinsen",
                          "Torsten Martinsen",
                          "1996",
                          N_("Oili_fy..."),
                          "RGB*, GRAY*",
                          GIMP_PLUGIN,
                          G_N_ELEMENTS (args), 0,
                          args, NULL);

  gimp_plugin_menu_register (PLUG_IN_PROC, "<Image>/Filters/Artistic");
}

static void
run (const gchar      *name,
     gint              nparams,
     const GimpParam  *param,
     gint             *nreturn_vals,
     GimpParam       **return_vals)
{
  static GimpParam   values[1];
  GimpDrawable      *drawable;
  GimpRunMode        run_mode;
  GimpPDBStatusType  status = GIMP_PDB_SUCCESS;

  INIT_I18N ();

  run_mode = param[0].data.d_int32;

  /*  Get the specified drawable  */
  drawable = gimp_drawable_get (param[2].data.d_drawable);
  gimp_tile_cache_ntiles (2 * drawable->ntile_cols);

  *nreturn_vals = 1;
  *return_vals  = values;

  values[0].type          = GIMP_PDB_STATUS;
  values[0].data.d_status = status;

  switch (run_mode)
    {
    case GIMP_RUN_INTERACTIVE:
      /*  Possibly retrieve data  */
      gimp_get_data (PLUG_IN_PROC, &ovals);

      /*  First acquire information with a dialog  */
      if (! oilify_dialog (drawable))
        return;
      break;

    case GIMP_RUN_NONINTERACTIVE:
      /*  Make sure all the arguments are there!  */
      if (nparams != 5)
        {
          status = GIMP_PDB_CALLING_ERROR;
        }
      else
        {
          ovals.mask_size = (gdouble) param[3].data.d_int32;
          ovals.mode = (gint) param[4].data.d_int32;

          if ((ovals.mask_size < 1.0) ||
              ((ovals.mode != MODE_INTEN) &&
               (ovals.mode != MODE_RGB)))
            status = GIMP_PDB_CALLING_ERROR;
        }
      break;

    case GIMP_RUN_WITH_LAST_VALS:
      /*  Possibly retrieve data  */
      gimp_get_data (PLUG_IN_PROC, &ovals);
      break;

    default:
      break;
    }

  /*  Make sure that the drawable is gray or RGB color  */
  if ((status == GIMP_PDB_SUCCESS) &&
      (gimp_drawable_is_rgb (drawable->drawable_id) ||
       gimp_drawable_is_gray (drawable->drawable_id)))
    {
      gimp_progress_init (_("Oil painting"));

      oilify (drawable, NULL);

      if (run_mode != GIMP_RUN_NONINTERACTIVE)
        gimp_displays_flush ();

      /*  Store data  */
      if (run_mode == GIMP_RUN_INTERACTIVE)
        gimp_set_data (PLUG_IN_PROC, &ovals, sizeof (OilifyVals));
    }
  else
    {
      /* gimp_message ("oilify: cannot operate on indexed color images"); */
      status = GIMP_PDB_EXECUTION_ERROR;
    }

  values[0].data.d_status = status;

  gimp_drawable_detach (drawable);
}

/*
 * For each i in [0, HISTSIZE), hist[i] is the number of occurrences of the
 * value i. Return a value in [0, HISTSIZE) weighted heavily toward the
 * most frequent values in the histogram.
 *
 * Assuming that hist_max is the maximum number of occurrences for any
 * value in the histogram, the weight given to each value i is
 *
 *         weight = (hist[i] / hist_max)^8
 *
 * The 8 is subjective. Lower powers give fuzzier edges.
 */
static inline guchar
weighted_average_value (gint hist[HISTSIZE])
{
  gint i;
  gint max = 1;
  gfloat weight;
  gfloat sum = 0.0;
  gfloat div = 1.0e-6;
  gint value;

  for (i = 0; i < HISTSIZE; i++)
    max = MAX (max, hist[i]);

  for (i = 0; i < HISTSIZE; i++)
  {
    weight = (gfloat) hist[i] / (gfloat) max;
    weight *= weight;
    weight *= weight;
    weight *= weight;  /* w' = w^8 */

    sum += weight * (gfloat) i;
    div += weight;
  }

  value = (gint) (sum / div);

  return (guchar) CLAMP (value, 0, HISTSIZE - 1);
}

/*
 * For each i in [0, HISTSIZE), hist[i] is the number of occurrences of
 * pixels with intensity i. hist_rgb[][i] is the average color of those
 * pixels with intensity i, each channel multiplied by hist[i]. Write to
 * dest a pixel whose color is a weighted average of all the colors in
 * hist_rgb[][], biased heavily toward those with the most frequently-
 * occurring intensities (as noted in hist[]).
 *
 * The weight formula is the same as in weighted_average_value().
 */
static inline void
weighted_average_color (gint    hist[HISTSIZE],
                        gint    hist_rgb[4][HISTSIZE],
                        guchar *dest,
                        gint    bytes)
{
  gint   i, b, c;
  gint   max = 1;
  gfloat weight;
  gfloat div = 1.0e-6;
  gfloat color[4] = { 0.0, 0.0, 0.0, 0.0 };

  for (i = 0; i < HISTSIZE; i++)
    max = MAX (max, hist[i]);

  for (i = 0; i < HISTSIZE; i++)
  {
    weight = (gfloat) hist[i] / (gfloat) max;
    weight *= weight;
    weight *= weight;
    weight *= weight;  /* w' = w^8 */

    if (hist[i] > 0)
      for (b = 0; b < bytes; b++)
        color[b] += weight * (gfloat) hist_rgb[b][i] / (gfloat) hist[i];

    div += weight;
  }

  for (b = 0; b < bytes; b++)
    {
      c = (gint) (color[b] / div);
      dest[b] = (guchar) CLAMP (c, 0, HISTSIZE - 1);
    }
}

/*
 * For all x and y as desired, replace the pixel at (x,y)
 * with a weighted average of the most frequently occurring
 * values in a circle of radius n centered at (x,y).
 */
static void
oilify (GimpDrawable *drawable,
        GimpPreview  *preview)
{
  gboolean      use_inten_alg;
  GimpPixelRgn  src_rgn, dest_rgn;
  gint          bytes;
  gint          width, height;
  guchar       *src_row, *src;
  guchar       *dest_row, *dest;
  gint          x, y, b, c, xx, yy, n;
  gint          x1, y1, x2, y2;
  gint          x3, y3, x4, y4;
  gint          Hist[HISTSIZE];
  gint          Hist_rgb[4][HISTSIZE];
  gpointer      pr1;
  gint          progress, max_progress;
  guchar       *src_buf;
  gchar        *mask_shape;
  gint          y_off;

  use_inten_alg = gimp_drawable_is_rgb (drawable->drawable_id) &&
                  ovals.mode == MODE_INTEN;

  /*  get the selection bounds  */
  if (preview)
    {
      gimp_preview_get_position (preview, &x1, &y1);
      gimp_preview_get_size (preview, &width, &height);

      x2 = x1 + width;
      y2 = y1 + height;
    }
  else
    {
      gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
      width  = x2 - x1;
      height = y2 - y1;
    }

  progress = 0;
  max_progress = width * height;

  bytes = drawable->bpp;

  n = (int) ovals.mask_size / 2;

  /*
   * mask_shape represents a (n+1)x(n+1) bitmap of one-quarter of a
   * circular disk, with radius n and center at (0,0). This is used in the
   * inner loop below so that we sample pixels only inside a circular area.
   * (Think of it as a lookup-table implementation of a distance function,
   * returning zero if the distance > n and nonzero otherwise.)
   */
  mask_shape = g_new (gchar, (n + 1) * (n + 1));

  for (x = 0; x <= n; x++)
    for (y = 0; y <= n; y++)
      mask_shape[y * (n + 1) + x] = x * x + y * y <= n * n;

  gimp_pixel_rgn_init (&dest_rgn, drawable,
                       x1, y1, width, height, (preview == NULL), TRUE);
  gimp_pixel_rgn_init (&src_rgn, drawable,
                       x1, y1, width, height, FALSE, FALSE);
  src_buf = g_new (guchar, width * height * bytes);
  gimp_pixel_rgn_get_rect (&src_rgn, src_buf, x1, y1, width, height);

  for (pr1 = gimp_pixel_rgns_register (1, &dest_rgn);
       pr1 != NULL;
       pr1 = gimp_pixel_rgns_process (pr1))
    {
      dest_row = dest_rgn.data;

      for (y = dest_rgn.y; y < (dest_rgn.y + dest_rgn.h); y++)
        {
          dest = dest_row;

          for (x = dest_rgn.x; x < (dest_rgn.x + dest_rgn.w); x++)
            {
              if (use_inten_alg)
                memset (Hist, 0, sizeof (Hist));

              memset (Hist_rgb, 0, sizeof (Hist_rgb));

              x3 = CLAMP ((x - n), x1, x2);
              y3 = CLAMP ((y - n), y1, y2);
              x4 = CLAMP ((x + n + 1), x1, x2);
              y4 = CLAMP ((y + n + 1), y1, y2);

              src_row = src_buf + ((y3 - y1) * width + (x3 - x1)) * bytes;

              for (yy = y3 ; yy < y4 ; yy++)
                {
		  y_off = ABS (yy - y) * (n + 1);
                  src = src_row;

                  for (xx = x3 ; xx < x4 ; xx++)
                    {
                      if (mask_shape[y_off + ABS(xx - x)])
                        {
                          if (use_inten_alg)
                            {
                              c = GIMP_RGB_LUMINANCE (src[0], src[1], src[2]);
                              ++Hist[c];
                              for (b = 0; b < bytes; b++)
                                Hist_rgb[b][c] += src[b];
                            }
                          else
                            {
                              for (b = 0; b < bytes; b++)
                                ++Hist_rgb[b][src[b]];
                            }
                        }

                      src += bytes;
                    }

                  src_row += width * bytes;
                }

              if (use_inten_alg)
                {
                  weighted_average_color (Hist, Hist_rgb, dest, bytes);
                }
              else
                {
                  for (b = 0; b < bytes; b++)
                    dest[b] = weighted_average_value (Hist_rgb[b]);
                }

              dest += bytes;
            }

          dest_row += dest_rgn.rowstride;
        }

      if (preview)
        {
          gimp_drawable_preview_draw_region (GIMP_DRAWABLE_PREVIEW (preview),
                                             &dest_rgn);
        }
      else
        {
          progress += dest_rgn.w * dest_rgn.h;
          if ((progress % 5) == 0)
            gimp_progress_update ((double) progress / (double) max_progress);
        }
    }

  g_free (src_buf);
  g_free (mask_shape);

  if (!preview)
    {
      /*  update the oil-painted region  */
      gimp_drawable_flush (drawable);
      gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
      gimp_drawable_update (drawable->drawable_id, x1, y1, width, height);
    }
}

static gint
oilify_dialog (GimpDrawable *drawable)
{
  GtkWidget *dialog;
  GtkWidget *main_vbox;
  GtkWidget *preview;
  GtkWidget *table;
  GtkWidget *toggle;
  GtkObject *adj;
  gboolean   run;

  gimp_ui_init (PLUG_IN_BINARY, FALSE);

  dialog = gimp_dialog_new (_("Oilify"), PLUG_IN_BINARY,
                            NULL, 0,
                            gimp_standard_help_func, PLUG_IN_PROC,

                            GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                            GTK_STOCK_OK,     GTK_RESPONSE_OK,

                            NULL);

  gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                           GTK_RESPONSE_OK,
                                           GTK_RESPONSE_CANCEL,
                                           -1);

  gimp_window_set_transient (GTK_WINDOW (dialog));

  main_vbox = gtk_vbox_new (FALSE, 12);
  gtk_container_set_border_width (GTK_CONTAINER (main_vbox), 12);
  gtk_container_add (GTK_CONTAINER (GTK_DIALOG (dialog)->vbox), main_vbox);
  gtk_widget_show (main_vbox);

  preview = gimp_drawable_preview_new (drawable, &ovals.preview);
  gtk_box_pack_start (GTK_BOX (main_vbox), preview, TRUE, TRUE, 0);
  gtk_widget_show (preview);
  g_signal_connect_swapped (preview, "invalidated",
                            G_CALLBACK (oilify), drawable);

  table = gtk_table_new (2, 3, FALSE);
  gtk_table_set_col_spacings (GTK_TABLE (table), 6);
  gtk_table_set_row_spacings (GTK_TABLE (table), 6);
  gtk_box_pack_start (GTK_BOX (main_vbox), table, FALSE, FALSE, 0);
  gtk_widget_show (table);

  adj = gimp_scale_entry_new (GTK_TABLE (table), 0, 0,
                              _("_Mask size:"), SCALE_WIDTH, 0,
                              ovals.mask_size, 3.0, 50.0, 1.0, 5.0, 0,
                              TRUE, 0, 0,
                              NULL, NULL);
  g_signal_connect (adj, "value-changed",
                    G_CALLBACK (gimp_double_adjustment_update),
                    &ovals.mask_size);
  g_signal_connect_swapped (adj, "value-changed",
                            G_CALLBACK (gimp_preview_invalidate),
                            preview);

  toggle = gtk_check_button_new_with_mnemonic (_("_Use intensity"));
  gtk_table_attach (GTK_TABLE (table), toggle, 0, 3, 1, 2, GTK_FILL, 0, 0, 0);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), ovals.mode);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (gimp_toggle_button_update),
                    &ovals.mode);
  g_signal_connect_swapped (toggle, "toggled",
                            G_CALLBACK (gimp_preview_invalidate),
                            preview);

  gtk_widget_show (dialog);

  run = (gimp_dialog_run (GIMP_DIALOG (dialog)) == GTK_RESPONSE_OK);

  gtk_widget_destroy (dialog);

  return run;
}