/* $Id$
 *
 * unsharp.c 0.10 -- This is a plug-in for the GIMP 1.0
 *  http://www.stdout.org/~winston/gimp/unsharp.html
 *  (now out of date)
 *
 * Copyright (C) 1999 Winston Chang
 *                    <winstonc@cs.wisc.edu>
 *                    <winston@stdout.org>
 *
 * 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 <stdlib.h>
#include <string.h>
#include <stdio.h>

#include <gtk/gtk.h>

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

#include "libgimp/stdplugins-intl.h"


#define PLUG_IN_VERSION "0.10"

#define SCALE_WIDTH  150
#define ENTRY_WIDTH    4

/* to show both pretty unoptimized code and ugly optimized code blocks
   There's really no reason to define this, unless you want to see how
   much pointer aritmetic can speed things up.  I find that it is about
   45% faster with the optimized code. */
/* #define READABLE_CODE */

/* uncomment this line to get a rough feel of how long the
   plug-in takes to run */
/* #define TIMER */

typedef struct
{
  gdouble radius;
  gdouble amount;
  gint    threshold;
} UnsharpMaskParams;

typedef struct
{
  gboolean  run;
} UnsharpMaskInterface;

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

static inline void  blur_line         (gdouble       *ctable,
                                       gdouble       *cmatrix,
                                       gint           cmatrix_length,
                                       guchar        *cur_col,
                                       guchar        *dest_col,
                                       gint           y,
                                       glong          bytes);
static gint      gen_convolve_matrix  (gdouble        std_dev,
                                       gdouble      **cmatrix);
static gdouble * gen_lookup_table     (gdouble       *cmatrix,
                                       gint           cmatrix_length);
static void      unsharp_region       (GimpPixelRgn   srcPTR,
                                       GimpPixelRgn   dstPTR,
                                       gint           width,
                                       gint           height,
                                       gint           bytes,
                                       gdouble        radius,
                                       gdouble        amount,
                                       gint           x1,
                                       gint           x2,
                                       gint           y1,
                                       gint           y2);

static void      unsharp_mask         (GimpDrawable  *drawable,
                                       gdouble        radius,
                                       gdouble        amount);

static gboolean  unsharp_mask_dialog  (void);


/* create a few globals, set default values */
static UnsharpMaskParams unsharp_params =
{
  5.0, /* default radius = 5 */
  0.5, /* default amount = .5 */
  0    /* default threshold = 0 */
};

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

MAIN ()

static void
query (void)
{
  static GimpParamDef args[] =
  {
    { GIMP_PDB_INT32,    "run_mode",  "Interactive, non-interactive" },
    { GIMP_PDB_IMAGE,    "image",     "(unused)" },
    { GIMP_PDB_DRAWABLE, "drawable",  "Drawable to draw on" },
    { GIMP_PDB_FLOAT,    "radius",    "Radius of gaussian blur (in pixels > 1.0)" },
    { GIMP_PDB_FLOAT,    "amount",    "Strength of effect" },
    { GIMP_PDB_FLOAT,    "threshold", "Threshold" }
  };

  gimp_install_procedure ("plug_in_unsharp_mask",
			  "An unsharp mask filter",
			  "The unsharp mask is a sharpening filter that works "
			  "by comparing using the difference of the image and "
			  "a blurred version of the image.  It is commonly "
			  "used on photographic images, and is provides a much "
			  "more pleasing result than the standard sharpen "
			  "filter.",
			  "Winston Chang <winstonc@cs.wisc.edu>",
			  "Winston Chang",
			  "1999",
			  N_("_Unsharp Mask..."),
			  "GRAY*, RGB*",
			  GIMP_PLUGIN,
			  G_N_ELEMENTS (args), 0,
			  args, NULL);

  gimp_plugin_menu_register ("plug_in_unsharp_mask",
                             N_("<Image>/Filters/Enhance"));
}

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;

#ifdef TIMER
  GTimer *timer = g_timer_new ();
#endif

  run_mode = param[0].data.d_int32;

  *return_vals  = values;
  *nreturn_vals = 1;

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

  INIT_I18N ();

  switch (run_mode)
    {
    case GIMP_RUN_INTERACTIVE:
      gimp_get_data ("plug_in_unsharp_mask", &unsharp_params);
      if (! unsharp_mask_dialog ()) return;
      break;

    case GIMP_RUN_NONINTERACTIVE:
      if (nparams != 6)
	{
	  status = GIMP_PDB_CALLING_ERROR;
	}
      else
	{
	  unsharp_params.radius = param[3].data.d_float;
	  unsharp_params.amount = param[4].data.d_float;
	  unsharp_params.threshold = param[5].data.d_int32;

	  /* make sure there are legal values */
	  if ((unsharp_params.radius < 0.0) ||
	      (unsharp_params.amount < 0.0))
	    status = GIMP_PDB_CALLING_ERROR;
	}
      break;

    case GIMP_RUN_WITH_LAST_VALS:
      gimp_get_data ("plug_in_unsharp_mask", &unsharp_params);
      break;

    default:
      break;
    }

  if (status == GIMP_PDB_SUCCESS)
    {
      drawable = gimp_drawable_get (param[2].data.d_drawable);
      gimp_tile_cache_ntiles(2 * (drawable->width / gimp_tile_width() + 1));

      /* here we go */
      unsharp_mask (drawable, unsharp_params.radius, unsharp_params.amount);

      /* values[0].data.d_status = status; */
      gimp_displays_flush ();

      /* set data for next use of filter */
      gimp_set_data ("plug_in_unsharp_mask", &unsharp_params,
		     sizeof (UnsharpMaskParams));

      /*fprintf(stderr, "%f %f\n", unsharp_params.radius, unsharp_params.amount);*/

      gimp_drawable_detach(drawable);
      values[0].data.d_status = status;
    }

#ifdef TIMER
  g_printerr ("%f seconds\n", g_timer_elapsed (timer));
  g_timer_destroy (timer);
#endif
}

static void
unsharp_mask (GimpDrawable *drawable,
	      gdouble       radius,
	      gdouble       amount)
{
  GimpPixelRgn srcPR, destPR;
  glong width, height;
  glong bytes;
  gint  x1, y1, x2, y2;

  /* Get the input */
  gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
  gimp_progress_init (_("Blurring..."));

  width = drawable->width;
  height = drawable->height;
  bytes = drawable->bpp;

  /* initialize pixel regions */
  gimp_pixel_rgn_init (&srcPR, drawable, 0, 0, width, height, FALSE, FALSE);
  gimp_pixel_rgn_init (&destPR, drawable, 0, 0, width, height, TRUE, TRUE);

  unsharp_region (srcPR, destPR, width, height, bytes, radius, amount,
		  x1, x2, y1, y2);

  gimp_drawable_flush(drawable);
  gimp_drawable_merge_shadow(drawable->drawable_id, TRUE);
  gimp_drawable_update(drawable->drawable_id, x1, y1, (x2-x1), (y2-y1));
}

/* perform an unsharp mask on the region, given a source region, dest.
   region, width and height of the regions, and corner coordinates of
   a subregion to act upon.  Everything outside the subregion is unaffected.
*/
static void
unsharp_region (GimpPixelRgn srcPR,
		GimpPixelRgn destPR,
		gint         width,
		gint         height,
		gint         bytes,
		gdouble      radius,
		gdouble      amount,
		gint         x1,
		gint         x2,
		gint         y1,
		gint         y2)
{
  guchar  *cur_col;
  guchar  *dest_col;
  guchar  *cur_row;
  guchar  *dest_row;
  gint     x;
  gint     y;
  gdouble *cmatrix = NULL;
  gint     cmatrix_length;
  gdouble *ctable;

  gint row, col;  /* these are counters for loops */

  /* these are used for the merging step */
  gint threshold;
  gint diff;
  gint value;
  gint u,v;

  /* find height and width of subregion to act on */
  x = x2-x1;
  y = y2-y1;

  /* generate convolution matrix and make sure it's smaller than each dimension */
  cmatrix_length = gen_convolve_matrix(radius, &cmatrix);
  /* generate lookup table */
  ctable = gen_lookup_table(cmatrix, cmatrix_length);

  /*  allocate row buffers  */
  cur_row  = g_new (guchar, x * bytes);
  dest_row = g_new (guchar, x * bytes);

  /* find height and width of subregion to act on */
  x = x2-x1;
  y = y2-y1;

  /* blank out a region of the destination memory area, I think */
  for (row = 0; row < y; row++)
    {
      gimp_pixel_rgn_get_row(&destPR, dest_row, x1, y1+row, (x2-x1));
      memset(dest_row, 0, x*bytes);
      gimp_pixel_rgn_set_row(&destPR, dest_row, x1, y1+row, (x2-x1));
    }

  /* blur the rows */
  for (row = 0; row < y; row++)
    {
      gimp_pixel_rgn_get_row(&srcPR, cur_row, x1, y1+row, x);
      gimp_pixel_rgn_get_row(&destPR, dest_row, x1, y1+row, x);
      blur_line(ctable, cmatrix, cmatrix_length, cur_row, dest_row, x, bytes);
      gimp_pixel_rgn_set_row(&destPR, dest_row, x1, y1+row, x);

      if (row%5 == 0)
	gimp_progress_update ((gdouble)row/(3*y));
    }

  /* allocate column buffers */
  cur_col  = g_new (guchar, y * bytes);
  dest_col = g_new (guchar, y * bytes);

  /* blur the cols */
  for (col = 0; col < x; col++)
    {
      gimp_pixel_rgn_get_col(&destPR, cur_col, x1+col, y1, y);
      gimp_pixel_rgn_get_col(&destPR, dest_col, x1+col, y1, y);
      blur_line(ctable, cmatrix, cmatrix_length, cur_col, dest_col, y, bytes);
      gimp_pixel_rgn_set_col(&destPR, dest_col, x1+col, y1, y);

      if (col%5 == 0)
	gimp_progress_update ((gdouble)col/(3*x) + 0.33);
    }

  gimp_progress_init (_("Merging..."));

  /* find integer value of threshold */
  threshold = unsharp_params.threshold;

  /* merge the source and destination (which currently contains
     the blurred version) images */
  for (row = 0; row < y; row++)
    {
      value = 0;
      /* get source row */
      gimp_pixel_rgn_get_row(&srcPR, cur_row, x1, y1+row, x);
      /* get dest row */
      gimp_pixel_rgn_get_row(&destPR, dest_row, x1, y1+row, x);
      /* combine the two */
      for (u = 0; u < x; u++)
	{
	  for (v = 0; v < bytes; v++)
	    {
	      diff = (cur_row[u*bytes+v] - dest_row[u*bytes+v]);
	      /* do tresholding */
	      if (abs (2 * diff) < threshold)
		diff = 0;

	      value = cur_row[u*bytes+v] + amount * diff;

	      if (value < 0) dest_row[u*bytes+v] =0;
	      else if (value > 255) dest_row[u*bytes+v] = 255;
	      else  dest_row[u*bytes+v] = value;
	    }
	}
      /* update progress bar every five rows */
      if (row%5 == 0)
        gimp_progress_update ((gdouble)row/(3*y) + 0.67);

      gimp_pixel_rgn_set_row(&destPR, dest_row, x1, y1+row, x);
    }

  /* free the memory we took */
  g_free(cur_row);
  g_free(dest_row);
  g_free(cur_col);
  g_free(dest_col);
  g_free(cmatrix);
  g_free(ctable);

}

/* this function is written as if it is blurring a column at a time,
   even though it can operate on rows, too.  There is no difference
   in the processing of the lines, at least to the blur_line function. */
static inline void
blur_line (gdouble *ctable,
	   gdouble *cmatrix,
	   gint     cmatrix_length,
	   guchar  *cur_col,
	   guchar  *dest_col,
	   gint     y,
	   glong    bytes)
{
  gdouble scale;
  gdouble sum;
  gint i=0, j=0;
  gint row;
  gint cmatrix_middle = cmatrix_length/2;

  gdouble *cmatrix_p;
  guchar  *cur_col_p;
  guchar  *cur_col_p1;
  guchar  *dest_col_p;
  gdouble *ctable_p;

  /* this first block is the same as the non-optimized version --
   * it is only used for very small pictures, so speed isn't a
   * big concern.
   */
  if (cmatrix_length > y)
    {
      for (row = 0; row < y ; row++)
	{
	  scale=0;
	  /* find the scale factor */
	  for (j = 0; j < y ; j++)
	    {
	      /* if the index is in bounds, add it to the scale counter */
	      if ((j + cmatrix_length/2 - row >= 0) &&
		  (j + cmatrix_length/2 - row < cmatrix_length))
		scale += cmatrix[j + cmatrix_length/2 - row];
	    }
	  for (i = 0; i<bytes; i++)
	    {
	      sum = 0;
	      for (j = 0; j < y; j++)
		{
		  if ((j >= row - cmatrix_length/2) &&
		      (j <= row + cmatrix_length/2))
		    sum += cur_col[j*bytes + i] * cmatrix[j];
		}
	      dest_col[row*bytes + i] = (guchar) ROUND (sum / scale);
	    }
	}
    }
  else
    {
      /* for the edge condition, we only use available info and scale to one */
      for (row = 0; row < cmatrix_middle; row++)
	{
	  /* find scale factor */
	  scale=0;
	  for (j = cmatrix_middle - row; j<cmatrix_length; j++)
	    scale += cmatrix[j];
	  for (i = 0; i<bytes; i++)
	    {
	      sum = 0;
	      for (j = cmatrix_middle - row; j<cmatrix_length; j++)
		{
		  sum += cur_col[(row + j-cmatrix_middle)*bytes + i] * cmatrix[j];
		}
	      dest_col[row*bytes + i] = (guchar) ROUND (sum / scale);
	    }
	}
      /* go through each pixel in each col */
      dest_col_p = dest_col + row*bytes;
      for (; row < y-cmatrix_middle; row++)
	{
	  cur_col_p = (row - cmatrix_middle) * bytes + cur_col;
	  for (i = 0; i<bytes; i++)
	    {
	      sum = 0;
	      cmatrix_p = cmatrix;
	      cur_col_p1 = cur_col_p;
	      ctable_p = ctable;
	      for (j = cmatrix_length; j>0; j--)
		{
		  sum += *(ctable_p + *cur_col_p1);
		  cur_col_p1 += bytes;
		  ctable_p += 256;
		}
	      cur_col_p++;
	      *(dest_col_p++) = ROUND (sum);
	    }
	}

      /* for the edge condition , we only use available info, and scale to one */
      for (; row < y; row++)
	{
	  /* find scale factor */
	  scale=0;
	  for (j = 0; j< y-row + cmatrix_middle; j++)
	    scale += cmatrix[j];
	  for (i = 0; i<bytes; i++)
	    {
	      sum = 0;
	      for (j = 0; j<y-row + cmatrix_middle; j++)
		{
		  sum += cur_col[(row + j-cmatrix_middle)*bytes + i] * cmatrix[j];
		}
	      dest_col[row*bytes + i] = (guchar) ROUND (sum / scale);
	    }
	}
    }
}

/* generates a 1-D convolution matrix to be used for each pass of
 * a two-pass gaussian blur.  Returns the length of the matrix.
 */
static gint
gen_convolve_matrix (gdouble   radius,
		     gdouble **cmatrix_p)
{
  gint matrix_length;
  gint matrix_midpoint;
  gdouble* cmatrix;
  gint i,j;
  gdouble std_dev;
  gdouble sum;

  /* we want to generate a matrix that goes out a certain radius
   * from the center, so we have to go out ceil(rad-0.5) pixels,
   * inlcuding the center pixel.  Of course, that's only in one direction,
   * so we have to go the same amount in the other direction, but not count
   * the center pixel again.  So we double the previous result and subtract
   * one.
   * The radius parameter that is passed to this function is used as
   * the standard deviation, and the radius of effect is the
   * standard deviation * 2.  It's a little confusing.
   */
  radius = fabs(radius) + 1.0;

  std_dev = radius;
  radius = std_dev * 2;

  /* go out 'radius' in each direction */
  matrix_length = 2 * ceil(radius-0.5) + 1;
  if (matrix_length <= 0) matrix_length = 1;
  matrix_midpoint = matrix_length/2 + 1;
  *cmatrix_p = g_new (gdouble, matrix_length);
  cmatrix = *cmatrix_p;

  /*  Now we fill the matrix by doing a numeric integration approximation
   * from -2*std_dev to 2*std_dev, sampling 50 points per pixel.
   * We do the bottom half, mirror it to the top half, then compute the
   * center point.  Otherwise asymmetric quantization errors will occur.
   *  The formula to integrate is e^-(x^2/2s^2).
   */

  /* first we do the top (right) half of matrix */
  for (i = matrix_length/2 + 1; i < matrix_length; i++)
    {
      double base_x = i - floor(matrix_length/2) - 0.5;
      sum = 0;
      for (j = 1; j <= 50; j++)
	{
	  if ( base_x+0.02*j <= radius )
	    sum += exp (-(base_x+0.02*j)*(base_x+0.02*j) /
			(2*std_dev*std_dev));
	}
      cmatrix[i] = sum/50;
    }

  /* mirror the thing to the bottom half */
  for (i=0; i<=matrix_length/2; i++) {
    cmatrix[i] = cmatrix[matrix_length-1-i];
  }

  /* find center val -- calculate an odd number of quanta to make it symmetric,
   * even if the center point is weighted slightly higher than others. */
  sum = 0;
  for (j=0; j<=50; j++)
    {
      sum += exp (-(0.5+0.02*j)*(0.5+0.02*j) /
		  (2*std_dev*std_dev));
    }
  cmatrix[matrix_length/2] = sum/51;

  /* normalize the distribution by scaling the total sum to one */
  sum=0;
  for (i=0; i<matrix_length; i++) sum += cmatrix[i];
  for (i=0; i<matrix_length; i++) cmatrix[i] = cmatrix[i] / sum;

  return matrix_length;
}

/* ----------------------- gen_lookup_table ----------------------- */
/* generates a lookup table for every possible product of 0-255 and
   each value in the convolution matrix.  The returned array is
   indexed first by matrix position, then by input multiplicand (?)
   value.
*/
static gdouble *
gen_lookup_table (gdouble *cmatrix,
		  gint     cmatrix_length)
{
  int i, j;
  gdouble* lookup_table = g_new (gdouble, cmatrix_length * 256);
  gdouble* lookup_table_p = lookup_table;
  gdouble* cmatrix_p      = cmatrix;

  for (i=0; i<cmatrix_length; i++)
    {
      for (j=0; j<256; j++)
	{
	  *(lookup_table_p++) = *cmatrix_p * (gdouble)j;
	}
      cmatrix_p++;
    }

  return lookup_table;
}

static gboolean
unsharp_mask_dialog (void)
{
  GtkWidget *window;
  GtkWidget *table;
  GtkObject *adj;
  gboolean   run;

  gimp_ui_init ("unsharp", TRUE);

  window = gimp_dialog_new (_("Unsharp Mask"), "unsharp",
                            NULL, 0,
			    gimp_standard_help_func, "plug-in-unsharp-mask",

                            GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                            GTK_STOCK_OK,     GTK_RESPONSE_OK,

                            NULL);

  table = gtk_table_new (3, 3, FALSE);
  gtk_table_set_col_spacings (GTK_TABLE (table), 6);
  gtk_table_set_row_spacings (GTK_TABLE (table), 6);
  gtk_container_set_border_width (GTK_CONTAINER (table), 12);
  gtk_box_pack_start (GTK_BOX (GTK_DIALOG (window)->vbox), table,
		      FALSE, FALSE, 0);
  gtk_widget_show (table);

  adj = gimp_scale_entry_new (GTK_TABLE (table), 0, 0,
			      _("_Radius:"), SCALE_WIDTH, ENTRY_WIDTH,
			      unsharp_params.radius, 0.1, 120.0, 0.1, 1.0, 1,
			      TRUE, 0, 0,
			      NULL, NULL);
  g_signal_connect (adj, "value_changed",
                    G_CALLBACK (gimp_double_adjustment_update),
                    &unsharp_params.radius);

  adj = gimp_scale_entry_new (GTK_TABLE (table), 0, 1,
			      _("_Amount:"), SCALE_WIDTH, ENTRY_WIDTH,
			      unsharp_params.amount, 0.0, 5.0, 0.01, 0.1, 2,
			      TRUE, 0, 0,
			      NULL, NULL);
  g_signal_connect (adj, "value_changed",
                    G_CALLBACK (gimp_double_adjustment_update),
                    &unsharp_params.amount);

  adj = gimp_scale_entry_new (GTK_TABLE (table), 0, 2,
			      _("_Threshold:"), SCALE_WIDTH, ENTRY_WIDTH,
			      unsharp_params.threshold, 0.0, 255.0, 1.0, 10.0, 0,
			      TRUE, 0, 0,
			      NULL, NULL);
  g_signal_connect (adj, "value_changed",
                    G_CALLBACK (gimp_int_adjustment_update),
                    &unsharp_params.threshold);

  gtk_widget_show (window);

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

  gtk_widget_destroy (window);

  return run;
}
