/* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <stdio.h>
#include <stdlib.h>
#include "appenv.h"
#include "buildmenu.h"
#include "channels_dialog.h"
#include "colormaps.h"
#include "cursorutil.h"
#include "disp_callbacks.h"
#include "drawable.h"
#include "gdisplay.h"
#include "gdisplayP.h"
#include "gdisplay_ops.h"
#include "general.h"
#include "gimage_mask.h"
#include "gimprc.h"
#include "gximage.h"
#include "image_render.h"
#include "info_window.h"
#include "interface.h"
#include "layers_dialog.h"
#include "linked.h"
#include "menus.h"
#include "plug_in.h"
#include "scale.h"
#include "scroll.h"
#include "tools.h"
#include "undo.h"
#include "tools.h"


#define OVERHEAD          25  /*  in units of pixel area  */
#define EPSILON           5

/* variable declarations */
link_ptr               display_list = NULL;
static int             display_num  = 1;
static GdkCursorType   default_gdisplay_cursor = GDK_TOP_LEFT_ARROW;

#define ROUND(x) ((int) (x + 0.5))

#define MAX_TITLE_BUF 4096

static char *image_type_strs[] =
{
  "RGB",
  "RGB-alpha",
  "grayscale",
  "grayscale-alpha",
  "indexed",
  "indexed-alpha"
};


/*  Local functions  */
static void       gdisplay_format_title     (GImage *, char *);
static void       gdisplay_delete           (GDisplay *);
static link_ptr   gdisplay_free_area_list   (link_ptr);
static link_ptr   gdisplay_process_area_list(link_ptr, GArea *);
static void       gdisplay_add_update_area  (GDisplay *, int, int, int, int);
static void       gdisplay_add_display_area (GDisplay *, int, int, int, int);
static void       gdisplay_paint_area       (GDisplay *, int, int, int, int);
static void       gdisplay_display_area     (GDisplay *, int, int, int, int);
static guint      gdisplay_hash             (GDisplay *);

static GHashTable *display_ht = NULL;


GDisplay*
gdisplay_new (GImage       *gimage,
	      unsigned int  scale)
{
  GDisplay *gdisp;
  char title [MAX_TITLE_BUF];
  int instance;

  /*  If there isn't an interface, never create a gdisplay  */
  if (no_interface)
    return NULL;

  /* format the title */
  gdisplay_format_title (gimage, title);

  instance = gimage->instance_count;
  gimage->instance_count++;
  gimage->ref_count++;

  /*
   *  Set all GDisplay parameters...
   */
  gdisp = (GDisplay *) g_malloc (sizeof (GDisplay));

  gdisp->offset_x = gdisp->offset_y = 0;
  gdisp->scale = scale;
  gdisp->gimage = gimage;
  gdisp->window_info_dialog = NULL;
  gdisp->depth = g_visual->depth;
  gdisp->select = NULL;
  gdisp->ID = display_num++;
  gdisp->instance = instance;
  gdisp->update_areas = NULL;
  gdisp->display_areas = NULL;
  gdisp->disp_xoffset = 0;
  gdisp->disp_yoffset = 0;
  gdisp->current_cursor = -1;
  gdisp->draw_guides = TRUE;
  gdisp->snap_to_guides = TRUE;

  /*  add the new display to the list so that it isn't lost  */
  display_list = append_to_list (display_list, (void *) gdisp);

  /*  create the shell for the image  */
  create_display_shell (gdisp->ID, gimage->width, gimage->height,
			title, gimage_base_type (gimage));

  /*  set the gdisplay colormap type and install the appropriate colormap  */
  gdisp->color_type = (gimage_base_type (gimage) == GRAY) ? GRAY : RGB;

  /*  set the user data  */
  if (!display_ht)
    display_ht = g_hash_table_new ((GHashFunc) gdisplay_hash, NULL);

  g_hash_table_insert (display_ht, gdisp->shell, gdisp);
  g_hash_table_insert (display_ht, gdisp->canvas, gdisp);

  /*  set the current tool cursor  */
  gdisplay_install_tool_cursor (gdisp, default_gdisplay_cursor);

  return gdisp;
}


static void
gdisplay_format_title (GImage *gimage,
		       char   *title)
{
  char *image_type_str;
  int empty;

  empty = gimage_is_empty (gimage);

  if (gimage_is_flat (gimage))
    image_type_str = image_type_strs[drawable_type (gimage_active_drawable (gimage))];
  else
    switch (gimage_base_type (gimage))
      {
      case RGB:
	image_type_str = (empty) ? "RGB-empty" : "RGB-layered";
	break;
      case GRAY:
	image_type_str = (empty) ? "grayscale-empty" : "grayscale-layered";
	break;
      case INDEXED:
	image_type_str = (empty) ? "indexed-empty" : "indexed-layered";
	break;
      default:
	image_type_str = NULL;
      }

  sprintf (title, "%s-%d.%d (%s)",
	   prune_filename (gimage_filename (gimage)),
	   gimage->ID, gimage->instance_count,
	   image_type_str);
}


static void
gdisplay_delete (GDisplay *gdisp)
{
  g_hash_table_remove (display_ht, gdisp->shell);
  g_hash_table_remove (display_ht, gdisp->canvas);

  /*  stop any active tool  */
  active_tool_control (HALT, (void *) gdisp);

  /*  free the selection structure  */
  selection_free (gdisp->select);

  /*  free the area lists  */
  gdisplay_free_area_list (gdisp->update_areas);
  gdisplay_free_area_list (gdisp->display_areas);

  /*  free the gimage  */
  gimage_delete (gdisp->gimage);

  /*  insure that if a window information dialog exists, it is removed  */
  if (gdisp->window_info_dialog)
    info_window_free (gdisp->window_info_dialog);

  /*  set popup_shell to NULL if appropriate */
  if (popup_shell == gdisp->shell)
    popup_shell= NULL;

  g_free (gdisp);
}


static link_ptr
gdisplay_free_area_list (link_ptr list)
{
  link_ptr l = list;
  GArea *ga;

  while (l)
    {
      /*  free the data  */
      ga = (GArea *) l->data;
      g_free (ga);

      l = next_item (l);
    }

  if (list)
    free_list (list);

  return NULL;
}


static link_ptr
gdisplay_process_area_list (link_ptr  list,
			    GArea    *ga1)
{
  link_ptr new_list;
  link_ptr l = list;
  int area1, area2, area3;
  GArea *ga2;

  /*  start new list off  */
  new_list = add_to_list (NULL, ga1);
  while (l)
    {
      /*  process the data  */
      ga2 = (GArea *) l->data;
      area1 = (ga1->x2 - ga1->x1) * (ga1->y2 - ga1->y1) + OVERHEAD;
      area2 = (ga2->x2 - ga2->x1) * (ga2->y2 - ga2->y1) + OVERHEAD;
      area3 = (MAXIMUM (ga2->x2, ga1->x2) - MINIMUM (ga2->x1, ga1->x1)) *
	(MAXIMUM (ga2->y2, ga1->y2) - MINIMUM (ga2->y1, ga1->y1)) + OVERHEAD;

      if ((area1 + area2) < area3)
	new_list = add_to_list (new_list, ga2);
      else
	{
	  ga1->x1 = MINIMUM (ga1->x1, ga2->x1);
	  ga1->y1 = MINIMUM (ga1->y1, ga2->y1);
	  ga1->x2 = MAXIMUM (ga1->x2, ga2->x2);
	  ga1->y2 = MAXIMUM (ga1->y2, ga2->y2);

	  g_free (ga2);
	}

      l = next_item (l);
    }

  if (list)
    free_list (list);

  return new_list;
}


void
gdisplay_flush (GDisplay *gdisp)
{
  GArea * ga;
  link_ptr list;

  /*  Flush the items in the displays and updates lists--
   *  but only if gdisplay has been mapped and exposed
   */
  if (!gdisp->select)
    return;

  /*  First the updates...  */
  list = gdisp->update_areas;
  while (list)
    {
      /*  Paint the area specified by the GArea  */
      ga = (GArea *) list->data;
      gdisplay_paint_area (gdisp, ga->x1, ga->y1,
			   (ga->x2 - ga->x1), (ga->y2 - ga->y1));

      list = next_item (list);
    }
  /*  Free the update lists  */
  gdisp->update_areas = gdisplay_free_area_list (gdisp->update_areas);

  /*  Next the displays...  */
  list = gdisp->display_areas;

  if (list)
    {
      /*  stop the currently active tool  */
      active_tool_control (PAUSE, (void *) gdisp);

      while (list)
	{
	  /*  Paint the area specified by the GArea  */
	  ga = (GArea *) list->data;
	  gdisplay_display_area (gdisp, ga->x1, ga->y1,
				 (ga->x2 - ga->x1), (ga->y2 - ga->y1));

	  list = next_item (list);
	}
      /*  Free the update lists  */
      gdisp->display_areas = gdisplay_free_area_list (gdisp->display_areas);

      /* draw the guides */
      gdisplay_draw_guides (gdisp);

      /* restart (and recalculate) the selection boundaries */
      selection_start (gdisp->select, TRUE);

      /* start the currently active tool */
      active_tool_control (RESUME, (void *) gdisp);
    }
}


void
gdisplay_draw_guides (GDisplay *gdisp)
{
  GList *tmp_list;
  Guide *guide;

  if (gdisp->draw_guides)
    {
      tmp_list = gdisp->gimage->guides;
      while (tmp_list)
	{
	  guide = tmp_list->data;
	  tmp_list = tmp_list->next;

	  gdisplay_draw_guide (gdisp, guide, FALSE);
	}
    }
}

void
gdisplay_draw_guide (GDisplay *gdisp,
		     Guide    *guide,
		     int       active)
{
  static GdkGC *normal_hgc = NULL;
  static GdkGC *active_hgc = NULL;
  static GdkGC *normal_vgc = NULL;
  static GdkGC *active_vgc = NULL;
  static int initialize = TRUE;
  int x1, x2;
  int y1, y2;
  int w, h;
  int x, y;

  if (guide->position < 0)
    return;

  if (initialize)
    {
      GdkGCValues values;
      char stipple[8] =
      {
	0xF0,    /*  ####----  */
	0xE1,    /*  ###----#  */
	0xC3,    /*  ##----##  */
	0x87,    /*  #----###  */
	0x0F,    /*  ----####  */
	0x1E,    /*  ---####-  */
	0x3C,    /*  --####--  */
	0x78,    /*  -####---  */
      };

      initialize = FALSE;

      values.foreground.pixel = gdisplay_black_pixel (gdisp);
      values.background.pixel = g_normal_guide_pixel;
      values.fill = GDK_OPAQUE_STIPPLED;
      values.stipple = gdk_bitmap_create_from_data (gdisp->canvas->window, (char*) stipple, 8, 1);
      normal_hgc = gdk_gc_new_with_values (gdisp->canvas->window, &values,
					  GDK_GC_FOREGROUND |
					  GDK_GC_BACKGROUND |
					  GDK_GC_FILL |
					  GDK_GC_STIPPLE);

      values.background.pixel = g_active_guide_pixel;
      active_hgc = gdk_gc_new_with_values (gdisp->canvas->window, &values,
					   GDK_GC_FOREGROUND |
					   GDK_GC_BACKGROUND |
					   GDK_GC_FILL |
					   GDK_GC_STIPPLE);

      values.foreground.pixel = gdisplay_black_pixel (gdisp);
      values.background.pixel = g_normal_guide_pixel;
      values.fill = GDK_OPAQUE_STIPPLED;
      values.stipple = gdk_bitmap_create_from_data (gdisp->canvas->window, (char*) stipple, 1, 8);
      normal_vgc = gdk_gc_new_with_values (gdisp->canvas->window, &values,
					  GDK_GC_FOREGROUND |
					  GDK_GC_BACKGROUND |
					  GDK_GC_FILL |
					  GDK_GC_STIPPLE);

      values.background.pixel = g_active_guide_pixel;
      active_vgc = gdk_gc_new_with_values (gdisp->canvas->window, &values,
					   GDK_GC_FOREGROUND |
					   GDK_GC_BACKGROUND |
					   GDK_GC_FILL |
					   GDK_GC_STIPPLE);
    }

  gdisplay_transform_coords (gdisp, 0, 0, &x1, &y1, FALSE);
  gdisplay_transform_coords (gdisp, gdisp->gimage->width, gdisp->gimage->height, &x2, &y2, FALSE);
  gdk_window_get_size (gdisp->canvas->window, &w, &h);

  if (x1 < 0) x1 = 0;
  if (y1 < 0) y1 = 0;
  if (x2 > w) x2 = w;
  if (y2 > h) y2 = h;

  if (guide->orientation == HORIZONTAL_GUIDE)
    {
      gdisplay_transform_coords (gdisp, 0, guide->position, &x, &y, FALSE);

      if (active)
	gdk_draw_line (gdisp->canvas->window, active_hgc, x1, y, x2, y);
      else
	gdk_draw_line (gdisp->canvas->window, normal_hgc, x1, y, x2, y);
    }
  else if (guide->orientation == VERTICAL_GUIDE)
    {
      gdisplay_transform_coords (gdisp, guide->position, 0, &x, &y, FALSE);

      if (active)
	gdk_draw_line (gdisp->canvas->window, active_vgc, x, y1, x, y2);
      else
	gdk_draw_line (gdisp->canvas->window, normal_vgc, x, y1, x, y2);
    }
}

Guide*
gdisplay_find_guide (GDisplay *gdisp,
		     int       x,
		     int       y)
{
  GList *tmp_list;
  Guide *guide;
  double scale;
  int offset_x, offset_y;
  int pos;

  if (gdisp->draw_guides)
    {
      offset_x = gdisp->offset_x - gdisp->disp_xoffset;
      offset_y = gdisp->offset_y - gdisp->disp_yoffset;
      scale = (SCALESRC (gdisp) == 1) ? SCALEDEST (gdisp) : 1.0 / SCALESRC (gdisp);

      tmp_list = gdisp->gimage->guides;
      while (tmp_list)
	{
	  guide = tmp_list->data;
	  tmp_list = tmp_list->next;

	  switch (guide->orientation)
	    {
	    case HORIZONTAL_GUIDE:
	      pos = (int) (scale * guide->position - offset_y);
	      if ((pos > (y - EPSILON)) &&
		  (pos < (y + EPSILON)))
		return guide;
	      break;
	    case VERTICAL_GUIDE:
	      pos = (int) (scale * guide->position - offset_x);
	      if ((pos > (x - EPSILON)) &&
		  (pos < (x + EPSILON)))
		return guide;
	      break;
	    }
	}
    }

  return NULL;
}

void
gdisplay_snap_point (GDisplay *gdisp,
		     int       x ,
		     int       y,
		     int      *tx,
		     int      *ty)
{
  GList *tmp_list;
  Guide *guide;
  double scale;
  int offset_x, offset_y;
  int minhdist, minvdist;
  int pos, dist;

  *tx = x;
  *ty = y;

  if (gdisp->draw_guides &&
      gdisp->snap_to_guides &&
      gdisp->gimage->guides)
    {
      offset_x = gdisp->offset_x - gdisp->disp_xoffset;
      offset_y = gdisp->offset_y - gdisp->disp_yoffset;
      scale = (SCALESRC (gdisp) == 1) ? SCALEDEST (gdisp) : 1.0 / SCALESRC (gdisp);

      minhdist = G_MAXINT;
      minvdist = G_MAXINT;

      tmp_list = gdisp->gimage->guides;
      while (tmp_list)
	{
	  guide = tmp_list->data;
	  tmp_list = tmp_list->next;

	  switch (guide->orientation)
	    {
	    case HORIZONTAL_GUIDE:
	      pos = (int) (scale * guide->position - offset_y);
	      if ((pos > (y - EPSILON)) &&
		  (pos < (y + EPSILON)))
		{
		  dist = pos - y;
		  dist = ABS (dist);

		  if (dist < minhdist)
		    {
		      minhdist = dist;
		      *ty = pos;
		    }
		}
	      break;
	    case VERTICAL_GUIDE:
	      pos = (int) (scale * guide->position - offset_x);
	      if ((pos > (x - EPSILON)) &&
		  (pos < (x + EPSILON)))
		{
		  dist = pos - x;
		  dist = ABS (dist);

		  if (dist < minvdist)
		    {
		      minvdist = dist;
		      *tx = pos;
		    }
		}
	      break;
	    }
	}
    }
}

void
gdisplay_snap_rectangle (GDisplay *gdisp,
			 int       x1,
			 int       y1,
			 int       x2,
			 int       y2,
			 int      *tx1,
			 int      *ty1)
{
  int nx1, ny1;
  int nx2, ny2;

  *tx1 = x1;
  *ty1 = y1;

  if (gdisp->draw_guides &&
      gdisp->snap_to_guides &&
      gdisp->gimage->guides)
    {
      gdisplay_snap_point (gdisp, x1, y1, &nx1, &ny1);
      gdisplay_snap_point (gdisp, x2, y2, &nx2, &ny2);

      if (x1 != nx1)
	*tx1 = nx1;
      else if (x2 != nx2)
	*tx1 = x1 + (nx2 - x2);

      if (y1 != ny1)
	*ty1 = ny1;
      else if (y2 != ny2)
	*ty1 = y1 + (ny2 - y2);
    }
}


void
gdisplay_remove_and_delete (GDisplay *gdisp)
{
  /* remove the display from the list */
  display_list = remove_from_list (display_list, (void *) gdisp);
  gdisplay_delete (gdisp);
}


static void
gdisplay_add_update_area (GDisplay *gdisp,
			  int       x,
			  int       y,
			  int       w,
			  int       h)
{
  GArea * ga;

  ga = (GArea *) g_malloc (sizeof (GArea));
  ga->x1 = BOUNDS (x, 0, gdisp->gimage->width);
  ga->y1 = BOUNDS (y, 0, gdisp->gimage->height);
  ga->x2 = BOUNDS (x + w, 0, gdisp->gimage->width);
  ga->y2 = BOUNDS (y + h, 0, gdisp->gimage->height);

  gdisp->update_areas = gdisplay_process_area_list (gdisp->update_areas, ga);
}


static void
gdisplay_add_display_area (GDisplay *gdisp,
			   int       x,
			   int       y,
			   int       w,
			   int       h)
{
  GArea * ga;

  ga = (GArea *) g_malloc (sizeof (GArea));

  ga->x1 = BOUNDS (x, 0, gdisp->disp_width);
  ga->y1 = BOUNDS (y, 0, gdisp->disp_height);
  ga->x2 = BOUNDS (x + w, 0, gdisp->disp_width);
  ga->y2 = BOUNDS (y + h, 0, gdisp->disp_height);

  gdisp->display_areas = gdisplay_process_area_list (gdisp->display_areas, ga);
}


static void
gdisplay_paint_area (GDisplay *gdisp,
		     int       x,
		     int       y,
		     int       w,
		     int       h)
{
  int x1, y1, x2, y2;

  /*  Bounds check  */
  x1 = BOUNDS (x, 0, gdisp->gimage->width);
  y1 = BOUNDS (y, 0, gdisp->gimage->height);
  x2 = BOUNDS (x + w, 0, gdisp->gimage->width);
  y2 = BOUNDS (y + h, 0, gdisp->gimage->height);
  x = x1;
  y = y1;
  w = (x2 - x1);
  h = (y2 - y1);

  /*  calculate the extents of the update as limited by what's visible  */
  gdisplay_untransform_coords (gdisp, 0, 0, &x1, &y1, FALSE, FALSE);
  gdisplay_untransform_coords (gdisp, gdisp->disp_width, gdisp->disp_height, &x2, &y2, FALSE, FALSE);

  gimage_invalidate (gdisp->gimage, x, y, w, h, x1, y1, x2, y2);

    /*  display the area  */
  gdisplay_transform_coords (gdisp, x, y, &x1, &y1, FALSE);
  gdisplay_transform_coords (gdisp, x + w, y + h, &x2, &y2, FALSE);
  gdisplay_expose_area (gdisp, x1, y1, (x2 - x1), (y2 - y1));
}


static void
gdisplay_display_area (GDisplay *gdisp,
		       int       x,
		       int       y,
		       int       w,
		       int       h)
{
  int sx, sy;
  int x1, y1;
  int x2, y2;
  int dx, dy;
  int i, j;

  sx = SCALE (gdisp, gdisp->gimage->width);
  sy = SCALE (gdisp, gdisp->gimage->height);

  /*  Bounds check  */
  x1 = BOUNDS (x, 0, gdisp->disp_width);
  y1 = BOUNDS (y, 0, gdisp->disp_height);
  x2 = BOUNDS (x + w, 0, gdisp->disp_width);
  y2 = BOUNDS (y + h, 0, gdisp->disp_height);

  if (x1 < gdisp->disp_xoffset)
    {
      gdk_window_clear_area (gdisp->canvas->window,
			     x, y, gdisp->disp_xoffset - x, h);

      x1 = gdisp->disp_xoffset;
    }

  if (y1 < gdisp->disp_yoffset)
    {
      gdk_window_clear_area (gdisp->canvas->window,
			     x, y, w, gdisp->disp_yoffset - y);

      y1 = gdisp->disp_yoffset;
    }

  if (x2 > (gdisp->disp_xoffset + sx))
    {
      gdk_window_clear_area (gdisp->canvas->window,
			     gdisp->disp_xoffset + sx, y,
			     x2 - (gdisp->disp_xoffset + sx), h);

      x2 = gdisp->disp_xoffset + sx;
    }

  if (y2 > (gdisp->disp_yoffset + sy))
    {
      gdk_window_clear_area (gdisp->canvas->window,
			     x, gdisp->disp_yoffset + sy,
			     w, y2 - (gdisp->disp_yoffset + sy));

      y2 = gdisp->disp_yoffset + sy;
    }

  /*  display the image in GXIMAGE_WIDTH x GXIMAGE_HEIGHT sized chunks */
  for (i = y1; i < y2; i += GXIMAGE_HEIGHT)
    for (j = x1; j < x2; j += GXIMAGE_WIDTH)
      {
	dx = (x2 - j < GXIMAGE_WIDTH) ? x2 - j : GXIMAGE_WIDTH;
	dy = (y2 - i < GXIMAGE_HEIGHT) ? y2 - i : GXIMAGE_HEIGHT;
	render_image (gdisp, j - gdisp->disp_xoffset, i - gdisp->disp_yoffset, dx, dy);
	gximage_put (gdisp->canvas->window,
		     j, i, dx, dy);
      }
}


int
gdisplay_mask_value (GDisplay *gdisp,
		     int       x,
		     int       y)
{
  /*  move the coordinates from screen space to image space  */
  gdisplay_untransform_coords (gdisp, x, y, &x, &y, FALSE, 0);

  return gimage_mask_value (gdisp->gimage, x, y);
}


int
gdisplay_mask_bounds (GDisplay *gdisp,
		      int      *x1,
		      int      *y1,
		      int      *x2,
		      int      *y2)
{
  Layer *layer;

  /*  If there is a floating selection, handle things differently  */
  if ((layer = gimage_floating_sel (gdisp->gimage)))
    {
      if (! channel_bounds (gimage_get_mask (gdisp->gimage), x1, y1, x2, y2))
	{
	  *x1 = layer->offset_x;
	  *y1 = layer->offset_y;
	  *x2 = layer->offset_x + layer->width;
	  *y2 = layer->offset_y + layer->height;
	}
      else
	{
	  *x1 = MINIMUM (layer->offset_x, *x1);
	  *y1 = MINIMUM (layer->offset_y, *y1);
	  *x2 = MAXIMUM (layer->offset_x + layer->width, *x2);
	  *y2 = MAXIMUM (layer->offset_y + layer->height, *y2);
	}
    }
  else if (! channel_bounds (gimage_get_mask (gdisp->gimage), x1, y1, x2, y2))
    return FALSE;

  gdisplay_transform_coords (gdisp, *x1, *y1, x1, y1, 0);
  gdisplay_transform_coords (gdisp, *x2, *y2, x2, y2, 0);

  /*  Make sure the extents are within bounds  */
  *x1 = BOUNDS (*x1, 0, gdisp->disp_width);
  *y1 = BOUNDS (*y1, 0, gdisp->disp_height);
  *x2 = BOUNDS (*x2, 0, gdisp->disp_width);
  *y2 = BOUNDS (*y2, 0, gdisp->disp_height);

  return TRUE;
}


void
gdisplay_transform_coords (GDisplay *gdisp,
			   int       x,
			   int       y,
			   int      *nx,
			   int      *ny,
			   int       use_offsets)
{
  double scale;
  int offset_x, offset_y;

  /*  transform from image coordinates to screen coordinates  */
  scale = (SCALESRC (gdisp) == 1) ? SCALEDEST (gdisp) :
    1.0 / SCALESRC (gdisp);

  if (use_offsets)
    drawable_offsets (gimage_active_drawable (gdisp->gimage), &offset_x, &offset_y);
  else
    {
      offset_x = offset_y = 0;
    }

  *nx = (int) (scale * (x + offset_x) - gdisp->offset_x);
  *ny = (int) (scale * (y + offset_y) - gdisp->offset_y);

  *nx += gdisp->disp_xoffset;
  *ny += gdisp->disp_yoffset;
}


void
gdisplay_untransform_coords (GDisplay *gdisp,
			     int       x,
			     int       y,
			     int      *nx,
			     int      *ny,
			     int       round,
			     int       use_offsets)
{
  double scale;
  int offset_x, offset_y;

  x -= gdisp->disp_xoffset;
  y -= gdisp->disp_yoffset;

  /*  transform from screen coordinates to image coordinates  */
  scale = (SCALESRC (gdisp) == 1) ? SCALEDEST (gdisp) :
    1.0 / SCALESRC (gdisp);

  if (use_offsets)
    drawable_offsets (gimage_active_drawable (gdisp->gimage), &offset_x, &offset_y);
  else
    {
      offset_x = offset_y = 0;
    }

  if (round)
    {
      *nx = ROUND ((x + gdisp->offset_x) / scale - offset_x);
      *ny = ROUND ((y + gdisp->offset_y) / scale - offset_y);
    }
  else
    {
      *nx = (int) ((x + gdisp->offset_x) / scale - offset_x);
      *ny = (int) ((y + gdisp->offset_y) / scale - offset_y);
    }
}


void
gdisplay_transform_coords_f (GDisplay *gdisp,
			     double    x,
			     double    y,
			     double   *nx,
			     double   *ny,
			     int       use_offsets)
{
  double scale;
  int offset_x, offset_y;

  /*  transform from gimp coordinates to screen coordinates  */
  scale = (SCALESRC (gdisp) == 1) ? SCALEDEST (gdisp) :
    1.0 / SCALESRC (gdisp);

  if (use_offsets)
    drawable_offsets (gimage_active_drawable (gdisp->gimage), &offset_x, &offset_y);
  else
    {
      offset_x = offset_y = 0;
    }

  *nx = scale * (x + offset_x) - gdisp->offset_x;
  *ny = scale * (y + offset_y) - gdisp->offset_y;

  *nx += gdisp->disp_xoffset;
  *ny += gdisp->disp_yoffset;
}


void
gdisplay_untransform_coords_f (GDisplay *gdisp,
			       double    x,
			       double    y,
			       double   *nx,
			       double   *ny,
			       int       use_offsets)
{
  double scale;
  int offset_x, offset_y;

  x -= gdisp->disp_xoffset;
  y -= gdisp->disp_yoffset;

  /*  transform from screen coordinates to gimp coordinates  */
  scale = (SCALESRC (gdisp) == 1) ? SCALEDEST (gdisp) :
    1.0 / SCALESRC (gdisp);

  if (use_offsets)
    drawable_offsets (gimage_active_drawable (gdisp->gimage), &offset_x, &offset_y);
  else
    {
      offset_x = offset_y = 0;
    }

  *nx = (x + gdisp->offset_x) / scale - offset_x;
  *ny = (y + gdisp->offset_y) / scale - offset_y;
}


/*  install and remove tool cursor from gdisplay...  */
void
gdisplay_install_tool_cursor (GDisplay      *gdisp,
			      GdkCursorType  cursor_type)
{
  if (gdisp->current_cursor != cursor_type)
    {
      gdisp->current_cursor = cursor_type;
      change_win_cursor (gdisp->canvas->window, cursor_type);
    }
}


void
gdisplay_remove_tool_cursor (GDisplay *gdisp)
{
  unset_win_cursor (gdisp->canvas->window);
}


void
gdisplay_set_menu_sensitivity (GDisplay *gdisp)
{
  Layer *layer;
  gint fs;
  gint aux;
  gint lm;
  gint lp;
  gint drawable;
  gint base_type;
  gint type;

  fs = (gimage_floating_sel (gdisp->gimage) != NULL);
  aux = (gimage_get_active_channel (gdisp->gimage) != NULL);
  if ((layer = gimage_get_active_layer (gdisp->gimage)) != NULL)
    lm = (layer->mask) ? TRUE : FALSE;
  else
    lm = FALSE;
  base_type = gimage_base_type (gdisp->gimage);
  lp = (gdisp->gimage->layers != NULL);

  type = -1;
  if (lp)
    {
      drawable = gimage_active_drawable (gdisp->gimage);
      type = drawable_type (drawable);
    }

  menus_set_sensitive ("<Image>/Layers/Raise Layer", !fs && !aux && lp);
  menus_set_sensitive ("<Image>/Layers/Lower Layer", !fs && !aux && lp);
  menus_set_sensitive ("<Image>/Layers/Anchor Layer", fs && !aux && lp);
  menus_set_sensitive ("<Image>/Layers/Merge Visible Layers", !fs && !aux && lp);
  menus_set_sensitive ("<Image>/Layers/Flatten Image", !fs && !aux && lp);
  menus_set_sensitive ("<Image>/Layers/Alpha To Selection", !aux && lp);
  menus_set_sensitive ("<Image>/Layers/Mask To Selection", !aux && lm && lp);

  menus_set_sensitive ("<Image>/Image/RGB", (base_type != RGB));
  menus_set_sensitive ("<Image>/Image/Grayscale", (base_type != GRAY));
  menus_set_sensitive ("<Image>/Image/Indexed", (base_type != INDEXED));

  menus_set_sensitive ("<Image>/Select", lp);
  menus_set_sensitive ("<Image>/Edit/Cut", lp);
  menus_set_sensitive ("<Image>/Edit/Copy", lp);
  menus_set_sensitive ("<Image>/Edit/Paste Into", lp);
  menus_set_sensitive ("<Image>/Edit/Clear", lp);
  menus_set_sensitive ("<Image>/Edit/Fill", lp);
  menus_set_sensitive ("<Image>/Edit/Stroke", lp);
  menus_set_sensitive ("<Image>/Edit/Cut Named", lp);
  menus_set_sensitive ("<Image>/Edit/Copy Named", lp);
  menus_set_sensitive ("<Image>/Image/Map", lp);
  menus_set_sensitive ("<Image>/Image/Adjust", lp);
  menus_set_sensitive ("<Image>/Image/Channel Ops/Offset", lp);
  menus_set_sensitive ("<Image>/Image/Histogram", lp);
  menus_set_sensitive ("<Image>/Filters", lp);

  /* save selection to channel */
  menus_set_sensitive ("<Image>/Select/Save To Channel", !fs);

  menus_set_state ("<Image>/View/Toggle Rulers", GTK_WIDGET_VISIBLE (gdisp->origin) ? 1 : 0);
  menus_set_state ("<Image>/View/Toggle Guides", gdisp->draw_guides);
  menus_set_state ("<Image>/View/Snap To Guides", gdisp->snap_to_guides);

  plug_in_set_menu_sensitivity (type);
}

void
gdisplay_expose_area (GDisplay *gdisp,
		      int       x,
		      int       y,
		      int       w,
		      int       h)
{
  gdisplay_add_display_area (gdisp, x, y, w, h);
}

void
gdisplay_expose_guide (GDisplay *gdisp,
		       Guide    *guide)
{
  int x1, y1;
  int x2, y2;
  int x, y;
  int w, h;

  if (guide->position < 0)
    return;

  gdisplay_transform_coords (gdisp, 0, 0, &x1, &y1, FALSE);
  gdisplay_transform_coords (gdisp, gdisp->disp_width, gdisp->disp_height, &x2, &y2, FALSE);
  gdisplay_transform_coords (gdisp, guide->position, guide->position, &x, &y, FALSE);
  gdk_window_get_size (gdisp->canvas->window, &w, &h);

  if (x1 < 0) x1 = 0;
  if (y1 < 0) y1 = 0;
  if (x2 > w) x2 = w;
  if (y2 > h) y2 = h;

  switch (guide->orientation)
    {
    case HORIZONTAL_GUIDE:
      gdisplay_expose_area (gdisp, x1, y, x2 - x1, 1);
      break;
    case VERTICAL_GUIDE:
      gdisplay_expose_area (gdisp, x, y1, 1, y2 - y1);
      break;
    }
}

void
gdisplay_expose_full (GDisplay *gdisp)
{
  gdisplay_add_display_area (gdisp, 0, 0,
			     gdisp->disp_width,
			     gdisp->disp_height);
}

/**************************************************/
/*  Functions independent of a specific gdisplay  */
/**************************************************/

GDisplay *
gdisplay_active ()
{
  GtkWidget *event_widget;
  GtkWidget *toplevel_widget;
  GdkEvent event;
  GDisplay *gdisp;

  /*  If the popup shell is valid, then get the gdisplay associated with that shell  */
  gtk_get_current_event (&event);
  event_widget = gtk_get_event_widget (&event);
  toplevel_widget = gtk_widget_get_toplevel (event_widget);
  gdisp = g_hash_table_lookup (display_ht, toplevel_widget);

  if (gdisp)
    return gdisp;

  if (popup_shell)
    {
      active_tool_control (DESTROY, gdisp);
      gdisp = gtk_object_get_user_data (GTK_OBJECT (popup_shell));
      return gdisp;
    }

  return NULL;
}


GDisplay *
gdisplay_get_ID (int ID)
{
  GDisplay *gdisp;
  link_ptr list = display_list;

  /*  Traverse the list of displays, returning the one that matches the ID  */
  /*  If no display in the list is a match, return NULL.                    */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->ID == ID)
	return gdisp;

      list = next_item (list);
    }

  return NULL;
}


void
gdisplays_update_title (int ID)
{
  GDisplay *gdisp;
  link_ptr list = display_list;
  char title [MAX_TITLE_BUF];

  /*  traverse the linked list of displays, handling each one  */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == ID)
	{
	  /* format the title */
	  gdisplay_format_title (gdisp->gimage, title);
	  gdk_window_set_title (gdisp->shell->window, title);
	}

      list = next_item (list);
    }
}


void
gdisplays_update_area (int ID,
		       int x,
		       int y,
		       int w,
		       int h)
{
  GDisplay *gdisp;
  link_ptr list = display_list;
  int x1, y1, x2, y2;
  int count = 0;

  /*  traverse the linked list of displays  */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == ID)
	{
	  /*  We only need to update the first instance that
	      we find of this gimage ID.  Otherwise, we would
	      be reconverting the same region unnecessarily.   */
	  if (! count)
	    gdisplay_add_update_area (gdisp, x, y, w, h);
	  else
	    {
	      gdisplay_transform_coords (gdisp, x, y, &x1, &y1, 0);
	      gdisplay_transform_coords (gdisp, x + w, y + h, &x2, &y2, 0);
	      gdisplay_add_display_area (gdisp, x1, y1, (x2 - x1), (y2 - y1));
	    }
	  count++;
	}

      list = next_item (list);
    }
}


void
gdisplays_expose_guides (int ID)
{
  GDisplay *gdisp;
  GList *tmp_list;
  link_ptr list;

  /*  traverse the linked list of displays, handling each one  */
  list = display_list;
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == ID)
	{
	  tmp_list = gdisp->gimage->guides;
	  while (tmp_list)
	    {
	      gdisplay_expose_guide (gdisp, tmp_list->data);
	      tmp_list = tmp_list->next;
	    }
	}

      list = next_item (list);
    }
}


void
gdisplays_expose_guide (int    ID,
			Guide *guide)
{
  GDisplay *gdisp;
  link_ptr list;

  /*  traverse the linked list of displays, handling each one  */
  list = display_list;
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == ID)
	gdisplay_expose_guide (gdisp, guide);

      list = next_item (list);
    }
}


void
gdisplays_update_full (int ID)
{
  GDisplay *gdisp;
  link_ptr list = display_list;
  int count = 0;

  /*  traverse the linked list of displays, handling each one  */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == ID)
	{
	  if (! count)
	    gdisplay_add_update_area (gdisp, 0, 0,
				      gdisp->gimage->width,
				      gdisp->gimage->height);
	  else
	    gdisplay_add_display_area (gdisp, 0, 0,
				       gdisp->disp_width,
				       gdisp->disp_height);

	  count++;
	}

      list = next_item (list);
    }
}


void
gdisplays_shrink_wrap (int ID)
{
  GDisplay *gdisp;
  link_ptr list = display_list;

  /*  traverse the linked list of displays, handling each one  */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == ID)
	shrink_wrap_display (gdisp);

      list = next_item (list);
    }
}


void
gdisplays_expose_full ()
{
  GDisplay *gdisp;
  link_ptr list = display_list;

  /*  traverse the linked list of displays, handling each one  */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      gdisplay_expose_full (gdisp);
      list = next_item (list);
    }
}


void
gdisplays_selection_visibility (int              gimage_ID,
				SelectionControl function)
{
  GDisplay *gdisp;
  link_ptr list = display_list;
  int count = 0;

  /*  traverse the linked list of displays, handling each one  */
  while (list)
    {
      gdisp = (GDisplay *) list->data;
      if (gdisp->gimage->ID == gimage_ID && gdisp->select)
	{
	  switch (function)
	    {
	    case SelectionOff:
	      selection_invis (gdisp->select);
	      break;
	    case SelectionLayerOff:
	      selection_layer_invis (gdisp->select);
	      break;
	    case SelectionOn:
	      selection_start (gdisp->select, TRUE);
	      break;
	    case SelectionPause:
	      selection_pause (gdisp->select);
	      break;
	    case SelectionResume:
	      selection_resume (gdisp->select);
	      break;
	    }
	  count++;
	}

      list = next_item (list);
    }
}


int
gdisplays_dirty ()
{
  int dirty = 0;
  link_ptr list = display_list;

  /*  traverse the linked list of displays  */
  while (list)
    {
      if (((GDisplay *) list->data)->gimage->dirty > 0)
	dirty = 1;
      list = next_item (list);
    }

  return dirty;
}


void
gdisplays_delete ()
{
  link_ptr list = display_list;

  /*  traverse the linked list of displays  */
  while (list)
    {
      gdisplay_delete ((GDisplay *) list->data);
      list = next_item (list);
    }

  /*  free up linked list data  */
  free_list (display_list);
}


void
gdisplays_flush ()
{
  static int flushing = FALSE;
  link_ptr list = display_list;

  /*  no flushing necessary without an interface  */
  if (no_interface)
    return;

  /*  this prevents multiple recursive calls to this procedure  */
  if (flushing == TRUE)
    return;

  flushing = TRUE;

  /*  traverse the linked list of displays  */
  while (list)
    {
      gdisplay_flush ((GDisplay *) list->data);
      list = next_item (list);
    }

  /*  for convenience, we call the layers dialog flush here  */
  layers_dialog_flush ();
  /*  for convenience, we call the channels dialog flush here  */
  channels_dialog_flush ();

  flushing = FALSE;
}

static guint
gdisplay_hash (GDisplay *display)
{
  return (gulong) display;
}
