/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * 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 <stdlib.h>
#include <string.h>
#include "appenv.h"
#include "draw_core.h"
#include "edit_selection.h"
#include "errors.h"
#include "free_select.h"
#include "gimage_mask.h"
#include "gdisplay.h"
#include "rect_select.h"
#include "selection_options.h"

#include "libgimp/gimpintl.h"

#define DEFAULT_MAX_INC  1024
#define ROUND(x) ((int) (x + 0.5))
#define SUPERSAMPLE      3
#define SUPERSAMPLE2     9

/*  the free selection structures  */

typedef struct _free_select FreeSelect;
struct _free_select
{
  DrawCore *      core;       /*  Core select object                      */
  int             num_pts;    /*  Number of points in the polygon         */
  int             op;         /*  selection operation (ADD, SUB, etc)     */
};

struct _FreeSelectPoint
{
  double x, y;
};


/*  the free selection tool options  */
static SelectionOptions * free_options = NULL;

/*  The global array of XPoints for drawing the polygon...  */
static GdkPoint *         global_pts = NULL;
static int                max_segs = 0;


/*  functions  */

static int
add_point (int num_pts, int x, int y)
{
  if (num_pts >= max_segs)
    {
      max_segs += DEFAULT_MAX_INC;

      global_pts = (GdkPoint *) g_realloc ((void *) global_pts, sizeof (GdkPoint) * max_segs);

      if (!global_pts)
	fatal_error (_("Unable to reallocate points array in free_select."));
    }

  global_pts[num_pts].x = x;
  global_pts[num_pts].y = y;

  return 1;
}


/*  Routines to scan convert the polygon  */

static GSList *
insert_into_sorted_list (GSList *list, int x)
{
  GSList *orig = list;
  GSList *rest;

  if (!list)
    return g_slist_prepend (list, (gpointer) ((long) x));

  while (list)
    {
      rest = g_slist_next (list);
      if (x < (long) list->data)
	{
	  rest = g_slist_prepend (rest, list->data);
	  list->next = rest;
	  list->data = (gpointer) ((long) x);
	  return orig;
	}
      else if (!rest)
	{
	  g_slist_append (list, (gpointer) ((long) x));
	  return orig;
	}
      list = g_slist_next (list);
    }

  return orig;
}

static void
convert_segment (GSList **scanlines, int width, int height,
		 int x1, int y1, int x2, int y2)
{
  int ydiff, y, tmp;
  float xinc, xstart;

  if (y1 > y2)
    { tmp = y2; y2 = y1; y1 = tmp;
      tmp = x2; x2 = x1; x1 = tmp; }
  ydiff = (y2 - y1);

  if ( ydiff )
    {
      xinc = (float) (x2 - x1) / (float) ydiff;
      xstart = x1 + 0.5 * xinc;
      for (y = y1 ; y < y2; y++)
	{
	  if (y >= 0 && y < height)
	    scanlines[y] = insert_into_sorted_list (scanlines[y], ROUND (xstart));
	  xstart += xinc;
	}
    }
}

static Channel *
scan_convert (GimpImage* gimage, int num_pts, FreeSelectPoint *pts,
	      int width, int height, int antialias)
{
  PixelRegion maskPR;
  Channel * mask;
  GSList **scanlines;
  GSList *list;
  unsigned char *buf, *b;
  int * vals, val;
  int start, end;
  int x, x2, w;
  int i, j;

  buf  = NULL;
  vals = NULL;

  if (num_pts < 3)
    return NULL;

  mask = channel_new_mask (gimage, width, height);

  if (antialias)
    {
      buf = (unsigned char *) g_malloc (width);
      width  *= SUPERSAMPLE;
      height *= SUPERSAMPLE;
      /* allocate value array  */
      vals = (int *) g_malloc (sizeof (int) * width);
    }

  scanlines = (GSList **) g_malloc (sizeof (GSList *) * height);
  for (i = 0; i < height; i++)
    scanlines[i] = NULL;

  for (i = 0; i < (num_pts - 1); i++)
    {
      if (antialias)
	convert_segment (scanlines, width, height,
			 (int) pts[i].x * SUPERSAMPLE, (int) pts[i].y * SUPERSAMPLE,
			 (int) pts[i + 1].x * SUPERSAMPLE, (int) pts[i + 1].y * SUPERSAMPLE);
      else
	convert_segment (scanlines, width, height,
			 (int) pts[i].x, (int) pts[i].y,
			 (int) pts[i + 1].x, (int) pts[i + 1].y);
    }

  /*  check for a connecting Point  */
  if (pts[num_pts - 1].x != pts[0].x ||
      pts[num_pts - 1].y != pts[0].y)
    {
      if (antialias)
	convert_segment (scanlines, width, height,
			 (int) pts[num_pts - 1].x * SUPERSAMPLE,
			 (int) pts[num_pts - 1].y * SUPERSAMPLE,
			 (int) pts[0].x * SUPERSAMPLE, (int) pts[0].y * SUPERSAMPLE);
      else
	convert_segment (scanlines, width, height,
			 (int) pts[num_pts - 1].x, (int) pts[num_pts - 1].y,
			 (int) pts[0].x, (int) pts[0].y);
    }

  pixel_region_init (&maskPR, drawable_data (GIMP_DRAWABLE(mask)), 0, 0, 
		     drawable_width (GIMP_DRAWABLE(mask)), 
		     drawable_height (GIMP_DRAWABLE(mask)), TRUE);
  for (i = 0; i < height; i++)
    {
      list = scanlines[i];

      /*  zero the vals array  */
      if (antialias && !(i % SUPERSAMPLE))
	memset (vals, 0, width * sizeof (int));

      while (list)
	{
	  x = (long) list->data;
	  list = g_slist_next(list);
	  if (!list)
	      g_message (_("Cannot properly scanline convert polygon!\n"));
	  else
	    {
	      /*  bounds checking  */
	      x = BOUNDS (x, 0, width);
	      x2 = BOUNDS ((long) list->data, 0, width);

	      w = x2 - x;

	      if (w > 0)
		{
		  if (! antialias)
		    channel_add_segment (mask, x, i, w, 255);
		  else
		    for (j = 0; j < w; j++)
		      vals[j + x] += 255;
		}
	      list = g_slist_next (list);
	    }
	}

      if (antialias && !((i+1) % SUPERSAMPLE))
	{
	  b = buf;
	  start = 0;
	  end = width;
	  for (j = start; j < end; j += SUPERSAMPLE)
	    {
	      val = 0;
	      for (x = 0; x < SUPERSAMPLE; x++)
		val += vals[j + x];

	      *b++ = (unsigned char) (val / SUPERSAMPLE2);
	    }

	  pixel_region_set_row (&maskPR, 0, (i / SUPERSAMPLE), 
				drawable_width (GIMP_DRAWABLE(mask)), buf);
	}

      g_slist_free (scanlines[i]);
    }

  if (antialias)
    {
      g_free (vals);
      g_free (buf);
    }

  g_free (scanlines);

  return mask;
}


/*************************************/
/*  Polygonal selection apparatus  */

void
free_select (GImage *gimage, int num_pts, FreeSelectPoint *pts, int op,
	     int antialias, int feather, double feather_radius)
{
  Channel *mask;

  /*  if applicable, replace the current selection  */
  /*  or insure that a floating selection is anchored down...  */
  if (op == REPLACE)
    gimage_mask_clear (gimage);
  else
    gimage_mask_undo (gimage);

  mask = scan_convert (gimage, num_pts, pts, gimage->width, gimage->height, antialias);

  if (mask)
    {
      if (feather)
	channel_feather (mask, gimage_get_mask (gimage),
			 feather_radius, op, 0, 0);
      else
	channel_combine_mask (gimage_get_mask (gimage),
			      mask, op, 0, 0);
      channel_delete (mask);
    }
}

void
free_select_button_press (Tool *tool, GdkEventButton *bevent,
			  gpointer gdisp_ptr)
{
  GDisplay *gdisp;
  FreeSelect *free_sel;

  gdisp = (GDisplay *) gdisp_ptr;
  free_sel = (FreeSelect *) tool->private;

  gdk_pointer_grab (gdisp->canvas->window, FALSE,
		    GDK_POINTER_MOTION_HINT_MASK | GDK_BUTTON1_MOTION_MASK | GDK_BUTTON_RELEASE_MASK,
		    NULL, NULL, bevent->time);

  tool->state = ACTIVE;
  tool->gdisp_ptr = gdisp_ptr;

  if (bevent->state & GDK_MOD1_MASK)
    {
      init_edit_selection (tool, gdisp_ptr, bevent, MaskTranslate);
      return;
    }
  else if ((bevent->state & GDK_SHIFT_MASK) && !(bevent->state & GDK_CONTROL_MASK))
    free_sel->op = ADD;
  else if ((bevent->state & GDK_CONTROL_MASK) && !(bevent->state & GDK_SHIFT_MASK))
    free_sel->op = SUB;
  else if ((bevent->state & GDK_CONTROL_MASK) && (bevent->state & GDK_SHIFT_MASK))
    free_sel->op = INTERSECT;
  else
    {
      if (! (layer_is_floating_sel (gimage_get_active_layer (gdisp->gimage))) &&
	  gdisplay_mask_value (gdisp, bevent->x, bevent->y) > HALF_WAY)
	{
	  init_edit_selection (tool, gdisp_ptr, bevent, MaskToLayerTranslate);
	  return;
	}
      free_sel->op = REPLACE;
    }

  add_point (0, bevent->x, bevent->y);
  free_sel->num_pts = 1;

  draw_core_start (free_sel->core,
		   gdisp->canvas->window,
		   tool);
}

void
free_select_button_release (Tool *tool, GdkEventButton *bevent,
			    gpointer gdisp_ptr)
{
  FreeSelect *free_sel;
  FreeSelectPoint *pts;
  GDisplay *gdisp;
  int i;

  gdisp = (GDisplay *) gdisp_ptr;
  free_sel = (FreeSelect *) tool->private;

  gdk_pointer_ungrab (bevent->time);
  gdk_flush ();

  draw_core_stop (free_sel->core, tool);

  tool->state = INACTIVE;

  /*  First take care of the case where the user "cancels" the action  */
  if (! (bevent->state & GDK_BUTTON3_MASK))
    {
      pts = (FreeSelectPoint *) g_malloc (sizeof (FreeSelectPoint) * free_sel->num_pts);

      for (i = 0; i < free_sel->num_pts; i++)
	{
	  gdisplay_untransform_coords_f (gdisp, global_pts[i].x, global_pts[i].y,
					 &pts[i].x, &pts[i].y, FALSE);
	}

      free_select (gdisp->gimage, free_sel->num_pts, pts, free_sel->op,
		   free_options->antialias, free_options->feather,
		   free_options->feather_radius);

      g_free (pts);

      gdisplays_flush ();
    }
}

void
free_select_motion (Tool *tool, GdkEventMotion *mevent, gpointer gdisp_ptr)
{
  FreeSelect *free_sel;
  GDisplay *gdisp;

  if (tool->state != ACTIVE)
    return;

  gdisp = (GDisplay *) gdisp_ptr;
  free_sel = (FreeSelect *) tool->private;

  if (add_point (free_sel->num_pts, mevent->x, mevent->y))
    {
      gdk_draw_line (free_sel->core->win, free_sel->core->gc,
		     global_pts[free_sel->num_pts - 1].x,
		     global_pts[free_sel->num_pts - 1].y,
		     global_pts[free_sel->num_pts].x,
		     global_pts[free_sel->num_pts].y);
      free_sel->num_pts ++;
    }
}

static void
free_select_control (Tool *tool, int action, gpointer gdisp_ptr)
{
  FreeSelect * free_sel;

  free_sel = (FreeSelect *) tool->private;

  switch (action)
    {
    case PAUSE :
      draw_core_pause (free_sel->core, tool);
      break;
    case RESUME :
      draw_core_resume (free_sel->core, tool);
      break;
    case HALT :
      draw_core_stop (free_sel->core, tool);
      break;
    }
}

void
free_select_draw (Tool *tool)
{
  FreeSelect * free_sel;
  int i;

  free_sel = (FreeSelect *) tool->private;

  for (i = 1; i < free_sel->num_pts; i++)
    gdk_draw_line (free_sel->core->win, free_sel->core->gc,
		   global_pts[i - 1].x, global_pts[i - 1].y,
		   global_pts[i].x, global_pts[i].y);
}

static void
free_select_options_reset ()
{
  selection_options_reset (free_options);
}

Tool *
tools_new_free_select (void)
{
  Tool * tool;
  FreeSelect * private;

  /*  The tool options  */
  if (!free_options)
    {
      free_options =
	selection_options_new (FREE_SELECT, free_select_options_reset);
      tools_register (FREE_SELECT, (ToolOptions *) free_options);
    }

  tool = (Tool *) g_malloc (sizeof (Tool));
  private = (FreeSelect *) g_malloc (sizeof (FreeSelect));

  private->core = draw_core_new (free_select_draw);
  private->num_pts = 0;

  tool->type = FREE_SELECT;
  tool->state = INACTIVE;
  tool->scroll_lock = 1;   /*  Do not allow scrolling  */
  tool->auto_snap_to = TRUE;
  tool->private = (void *) private;
 
 tool->button_press_func = free_select_button_press;
  tool->button_release_func = free_select_button_release;
  tool->motion_func = free_select_motion;
  tool->arrow_keys_func = standard_arrow_keys_func;
  tool->cursor_update_func = rect_select_cursor_update;
  tool->control_func = free_select_control;
  tool->preserve = TRUE;

  return tool;
}

void
tools_free_free_select (Tool *tool)
{
  FreeSelect * free_sel;

  free_sel = (FreeSelect *) tool->private;

  draw_core_free (free_sel->core);
  g_free (free_sel);
}