/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * Apply lens plug-in --- makes your selected part of the image look like it
 *                        is viewed under a solid lens.
 * Copyright (C) 1997 Morten Eriksen
 * mortene@pvv.ntnu.no
 * (If you do anything cool with this plug-in, or have ideas for
 * improvements (which aren't on my ToDo-list) - send me an email).
 *
 * 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.
 */

/* Version 0.1:
 * 
 * First release. No known serious bugs, and basically does what you want.
 * All fancy features postponed until the next release, though. :)
 *
 */

/*
  TO DO:
  - antialiasing
  - preview image
  - adjustable (R, G, B and A) filter
  - optimize for speed!
  - refraction index warning dialog box when value < 1.0
  - use "true" lens with specified thickness
  - option to apply inverted lens
  - adjustable "c" value in the ellipsoid formula
  - radiobuttons for "ellipsoid" or "only horiz" and "only vert" (like in the
    Ad*b* Ph*t*sh*p Spherify plug-in..)
  - clean up source code
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>

#include <gtk/gtk.h>

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

#include "libgimp/stdplugins-intl.h"

#define ENTRY_WIDTH 100

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

static void drawlens    (GimpDrawable *drawable);

static gint lens_dialog (GimpDrawable *drawable);

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

typedef struct
{
  gdouble refraction;
  gint    keep_surr;
  gint    use_bkgr;
  gint    set_transparent;
} LensValues;

static LensValues lvals =
{
  /* Lens refraction value */
  1.7,
  /* Surroundings options */
  TRUE, FALSE, FALSE
};

typedef struct
{
  gint run;
} LensInterface;

static LensInterface bint =
{
  FALSE  /*  run  */
};

MAIN ()

static void
query (void)
{
  static 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_FLOAT, "refraction", "Lens refraction index" },
    { GIMP_PDB_INT32, "keep_surroundings", "Keep lens surroundings" },
    { GIMP_PDB_INT32, "set_background", "Set lens surroundings to bkgr value" },
    { GIMP_PDB_INT32, "set_transparent", "Set lens surroundings transparent" }
  };

  gimp_install_procedure ("plug_in_applylens",
			  "Apply a lens effect",
			  "This plug-in uses Snell's law to draw an ellipsoid lens over the image",
			  "Morten Eriksen",
			  "Morten Eriksen",
			  "1997",
			  N_("<Image>/Filters/Glass Effects/Apply Lens..."),
			  "RGB*, GRAY*, INDEXED*",
			  GIMP_PLUGIN,
			  G_N_ELEMENTS (args), 0,
			  args, NULL);
}

static void
run (gchar   *name,
     gint     nparams,
     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;

  values[0].type = GIMP_PDB_STATUS;
  values[0].data.d_status = status;
  
  *nreturn_vals = 1;
  *return_vals = values;
  
  drawable = gimp_drawable_get (param[2].data.d_drawable);

  switch(run_mode)
    {
    case GIMP_RUN_INTERACTIVE:
      gimp_get_data ("plug_in_applylens", &lvals);
      if(!lens_dialog (drawable))
	return;
      break;

    case GIMP_RUN_NONINTERACTIVE:
      if (nparams != 7)
	status = GIMP_PDB_CALLING_ERROR;

      if (status == GIMP_PDB_SUCCESS)
	{
	  lvals.refraction = param[3].data.d_float;
	  lvals.keep_surr = param[4].data.d_int32;
	  lvals.use_bkgr = param[5].data.d_int32;
	  lvals.set_transparent = param[6].data.d_int32;
	}

      if (status == GIMP_PDB_SUCCESS && (lvals.refraction < 1.0))
	status = GIMP_PDB_CALLING_ERROR;
      break;

    case GIMP_RUN_WITH_LAST_VALS:
      gimp_get_data ("plug_in_applylens", &lvals);
      break;
    
    default:
      break;
    }

  gimp_tile_cache_ntiles (2 * (drawable->width / gimp_tile_width () + 1));
  gimp_progress_init (_("Applying lens..."));
  drawlens (drawable);

  if (run_mode != GIMP_RUN_NONINTERACTIVE)
    gimp_displays_flush ();
  if (run_mode == GIMP_RUN_INTERACTIVE)
    gimp_set_data ("plug_in_applylens", &lvals, sizeof (LensValues));

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

/*
  Ellipsoid formula: x^2/a^2 + y^2/b^2 + z^2/c^2 = 1
 */
static void
find_projected_pos (gfloat  a2,
		    gfloat  b2,
		    gfloat  c2,
		    gfloat  x,
		    gfloat  y,
		    gfloat *projx,
		    gfloat *projy)
{
  gfloat n[3];
  gfloat nxangle, nyangle, theta1, theta2;
  gfloat ri1 = 1.0;
  gfloat ri2 = lvals.refraction;

  n[0] = x;
  n[1] = y;
  n[2] = sqrt ((1 - x * x / a2 - y * y / b2) * c2);

  nxangle = acos (n[0] / sqrt(n[0] * n[0] + n[2] * n[2]));
  theta1 = G_PI / 2 - nxangle;
  theta2 = asin (sin (theta1) * ri1 / ri2);
  theta2 = G_PI / 2 - nxangle - theta2;
  *projx = x - tan (theta2) * n[2];

  nyangle = acos (n[1]/sqrt (n[1] * n[1] + n[2] * n[2]));
  theta1 = G_PI / 2 - nyangle;
  theta2 = asin (sin (theta1) * ri1 / ri2);
  theta2 = G_PI / 2 - nyangle - theta2;
  *projy = y - tan (theta2) * n[2];
}

static void
drawlens (GimpDrawable *drawable)
{
  GimpImageType drawtype = gimp_drawable_type (drawable->drawable_id);
  GimpPixelRgn  srcPR, destPR;
  gint     width, height;
  gint     bytes;
  gint     row;
  gint     x1, y1, x2, y2;
  guchar  *src, *dest;
  gint     i, col;
  gfloat   regionwidth, regionheight, dx, dy, xsqr, ysqr;
  gfloat   a, b, c, asqr, bsqr, csqr, x, y;
  glong    pixelpos, pos;
  GimpRGB  background;
  guchar   bgr_red, bgr_blue, bgr_green;
  guchar   alphaval;

  gimp_palette_get_background (&background);
  gimp_rgb_get_uchar (&background, 
		      &bgr_red, &bgr_green, &bgr_blue);

  gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
  regionwidth = x2 - x1;
  a = regionwidth / 2;
  regionheight = y2 - y1;
  b = regionheight / 2;

  c = MIN (a, b);

  asqr = a * a;
  bsqr = b * b;
  csqr = c * c;

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

  gimp_pixel_rgn_init (&srcPR, drawable, 0, 0, width, height, FALSE, FALSE);
  gimp_pixel_rgn_init (&destPR, drawable, 0, 0, width, height, TRUE, TRUE);

  src  = g_malloc ((x2 - x1) * (y2 - y1) * bytes);
  dest = g_malloc ((x2 - x1) * (y2 - y1) * bytes);
  gimp_pixel_rgn_get_rect (&srcPR, src, x1, y1, regionwidth, regionheight);

  for (col = 0; col < regionwidth; col++)
    {
      dx = (gfloat) col - a + 0.5;
      xsqr = dx * dx;
      for (row = 0; row < regionheight; row++)
	{
	  pixelpos = (col + row * regionwidth) * bytes;
	  dy = -((gfloat) row - b) - 0.5;
	  ysqr = dy * dy;
	  if (ysqr < (bsqr - (bsqr * xsqr) / asqr))
	    {
	      find_projected_pos (asqr, bsqr, csqr, dx, dy, &x, &y);
	      y = -y;
	      pos = ((gint) (y + b) * regionwidth + (gint) (x + a)) * bytes;

	      for (i = 0; i < bytes; i++)
		{
		  dest[pixelpos + i] = src[pos + i];
		}
	    }
	  else
	    {
	      if (lvals.keep_surr)
		{
		  for (i = 0; i < bytes; i++)
		    {
		      dest[pixelpos + i] = src[pixelpos + i];
		    }
		}
	      else
		{
		  if (lvals.set_transparent)
		    alphaval = 0;
		  else
		    alphaval = 255;

		  switch (drawtype)
		    {
		    case GIMP_INDEXEDA_IMAGE:
		      dest[pixelpos + 1] = alphaval;
		    case GIMP_INDEXED_IMAGE:
		      dest[pixelpos + 0] = 0;
		      break;

		    case GIMP_RGBA_IMAGE:
		      dest[pixelpos + 3] = alphaval;
		    case GIMP_RGB_IMAGE:
		      dest[pixelpos + 0] = bgr_red;
		      dest[pixelpos + 1] = bgr_green;
		      dest[pixelpos + 2] = bgr_blue;
		      break;

		    case GIMP_GRAYA_IMAGE:
		      dest[pixelpos + 1] = alphaval;
		    case GIMP_GRAY_IMAGE:
		      dest[pixelpos+0] = bgr_red;
		      break;
		    }
		}
	    }
	}
      
      if (((gint) (regionwidth-col) % 5) == 0)
	gimp_progress_update ((gdouble) col / (gdouble) regionwidth);
    }

  gimp_pixel_rgn_set_rect (&destPR, dest, x1, y1, regionwidth, regionheight);
  g_free (src);
  g_free (dest);

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

static void
lens_ok_callback (GtkWidget *widget,
		  gpointer   data)
{
  bint.run = TRUE;

  gtk_widget_destroy (GTK_WIDGET (data));
}

static gint
lens_dialog (GimpDrawable *drawable)
{
  GtkWidget *dlg;
  GtkWidget *label;
  GtkWidget *toggle;
  GtkWidget *frame;
  GtkWidget *vbox;
  GtkWidget *sep;
  GtkWidget *hbox;
  GtkWidget *spinbutton;
  GtkObject *adj;

  gimp_ui_init ("apply_lens", FALSE);

  dlg = gimp_dialog_new (_("Lens Effect"), "apply_lens",
			 gimp_standard_help_func, "filters/apply_lens.html",
			 GTK_WIN_POS_MOUSE,
			 FALSE, TRUE, FALSE,

			 GTK_STOCK_CANCEL, gtk_widget_destroy,
			 NULL, 1, NULL, FALSE, TRUE,

			 GTK_STOCK_OK, lens_ok_callback,
			 NULL, NULL, NULL, TRUE, FALSE,

			 NULL);

  g_signal_connect (dlg, "destroy",
                    G_CALLBACK (gtk_main_quit),
                    NULL);

  frame = gtk_frame_new (_("Parameter Settings"));
  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_ETCHED_IN);
  gtk_container_set_border_width (GTK_CONTAINER (frame), 6);
  gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dlg)->vbox), frame, TRUE, TRUE, 0);

  vbox = gtk_vbox_new (FALSE, 2);
  gtk_container_set_border_width (GTK_CONTAINER (vbox), 4);
  gtk_container_add (GTK_CONTAINER (frame), vbox);

  toggle = gtk_radio_button_new_with_mnemonic_from_widget
    (NULL, _("_Keep Original Surroundings"));
  gtk_box_pack_start (GTK_BOX (vbox), toggle, FALSE, FALSE, 0);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), lvals.keep_surr);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (gimp_toggle_button_update),
                    &lvals.keep_surr);

  toggle = gtk_radio_button_new_with_mnemonic_from_widget
    (GTK_RADIO_BUTTON (toggle),
     gimp_drawable_is_indexed (drawable->drawable_id)
     ? _("_Set Surroundings to Index 0")
     : _("_Set Surroundings to Background Color"));
  gtk_box_pack_start(GTK_BOX (vbox), toggle, FALSE, FALSE, 0);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), lvals.use_bkgr);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (gimp_toggle_button_update),
                    &lvals.use_bkgr);

  if (gimp_drawable_has_alpha (drawable->drawable_id))
    {
      toggle = gtk_radio_button_new_with_mnemonic_from_widget
        (GTK_RADIO_BUTTON (toggle), _("_Make Surroundings Transparent"));
      gtk_box_pack_start (GTK_BOX (vbox), toggle, FALSE, FALSE, 0);
      gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle),
				    lvals.set_transparent);
      gtk_widget_show (toggle);

      g_signal_connect (toggle, "toggled",
                        G_CALLBACK (gimp_toggle_button_update),
                        &lvals.set_transparent);
  }

  sep = gtk_hseparator_new ();
  gtk_box_pack_start (GTK_BOX (vbox), sep, FALSE, FALSE, 2);
  gtk_widget_show (sep);

  hbox = gtk_hbox_new (FALSE, 4);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);

  label = gtk_label_new_with_mnemonic (_("_Lens Refraction Index:"));
  gtk_box_pack_start (GTK_BOX (hbox), label, FALSE, FALSE, 0);
  gtk_widget_show (label);

  spinbutton = gimp_spin_button_new (&adj, lvals.refraction,
				     1.0, 100.0, 0.1, 1.0, 0, 1, 2);
  gtk_box_pack_start (GTK_BOX (hbox), spinbutton, FALSE, FALSE, 0);
  gtk_widget_show (spinbutton);

  gtk_label_set_mnemonic_widget (GTK_LABEL (label), spinbutton);

  g_signal_connect (adj, "value_changed",
                    G_CALLBACK (gimp_double_adjustment_update),
                    &lvals.refraction);

  gtk_widget_show (hbox);
  gtk_widget_show (vbox);
  gtk_widget_show (frame);
  gtk_widget_show (dlg);

  gtk_main ();
  gdk_flush ();

  return bint.run;
}