/* 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 "config.h"

#include <glib-object.h>

#include "libgimpmath/gimpmath.h"

#include "core-types.h"

#include "base/boundary.h"
#include "base/pixel-region.h"
#include "base/tile-manager.h"

#include "paint-funcs/paint-funcs.h"

#include "gimpimage.h"
#include "gimpimage-undo.h"
#include "gimpimage-undo-push.h"
#include "gimplayer.h"
#include "gimplayer-floating-sel.h"
#include "gimplayermask.h"

#include "gimp-intl.h"


void
floating_sel_attach (GimpLayer    *layer,
		     GimpDrawable *drawable)
{
  GimpImage *gimage;
  GimpLayer *floating_sel;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (GIMP_IS_DRAWABLE (drawable));
  g_return_if_fail (gimp_item_is_attached (GIMP_ITEM (drawable)));
  g_return_if_fail (drawable != GIMP_DRAWABLE (layer));
  g_return_if_fail (gimp_item_get_image (GIMP_ITEM (layer)) ==
                    gimp_item_get_image (GIMP_ITEM (drawable)));

  gimage = gimp_item_get_image (GIMP_ITEM (drawable));

  floating_sel = gimp_image_floating_sel (gimage);

  /*  If there is already a floating selection, anchor it  */
  if (floating_sel)
    {
      floating_sel_anchor (floating_sel);

      /*  if we were pasting to the old floating selection, paste now
       *  to the drawable
       */
      if (drawable == (GimpDrawable *) floating_sel)
	drawable = gimp_image_active_drawable (gimage);
    }

  /*  set the drawable and allocate a backing store  */
  gimp_layer_set_preserve_trans (layer, TRUE, FALSE);
  layer->fs.drawable      = drawable;
  layer->fs.backing_store = tile_manager_new (GIMP_ITEM (layer)->width,
                                              GIMP_ITEM (layer)->height,
                                              gimp_drawable_bytes (drawable));

  /*  add the layer to the gimage  */
  gimp_image_add_layer (gimage, layer, 0);

  /*  store the affected area from the drawable in the backing store  */
  floating_sel_rigor (layer, TRUE);
}

void
floating_sel_remove (GimpLayer *layer)
{
  GimpImage *gimage;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  gimage = gimp_item_get_image (GIMP_ITEM (layer->fs.drawable));

  gimp_image_undo_group_start (gimage, GIMP_UNDO_GROUP_FS_REMOVE,
                               _("Remove Floating Selection"));

  /*  store the affected area from the drawable in the backing store  */
  floating_sel_relax (layer, TRUE);

  /*  Invalidate the preview of the obscured drawable.  We do this here
   *  because it will not be done until the floating selection is removed,
   *  at which point the obscured drawable's preview will not be declared
   *  invalid.
   */
  gimp_viewable_invalidate_preview (GIMP_VIEWABLE (layer));

  /*  remove the layer from the gimage  */
  gimp_image_remove_layer (gimage, layer);

  gimp_image_undo_group_end (gimage);
}

void
floating_sel_anchor (GimpLayer *layer)
{
  GimpImage    *gimage;
  GimpDrawable *drawable;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  gimage = gimp_item_get_image (GIMP_ITEM (layer));

  if (! gimp_layer_is_floating_sel (layer))
    {
      g_message (_("Cannot anchor this layer because "
		   "it is not a floating selection."));
      return;
    }

  /*  Start a floating selection anchoring undo  */
  gimp_image_undo_group_start (gimage, GIMP_UNDO_GROUP_FS_ANCHOR,
                               _("Anchor Floating Selection"));

  /* Invalidate the previews of the layer that will be composited
   * with the floating section.
   */
  gimp_viewable_invalidate_preview (GIMP_VIEWABLE (layer->fs.drawable));

  /*  Relax the floating selection  */
  floating_sel_relax (layer, TRUE);

  /*  Composite the floating selection contents  */
  floating_sel_composite (layer,
			  GIMP_ITEM (layer)->offset_x,
			  GIMP_ITEM (layer)->offset_y,
			  GIMP_ITEM (layer)->width,
			  GIMP_ITEM (layer)->height, TRUE);

  drawable = layer->fs.drawable;

  /*  remove the floating selection  */
  gimp_image_remove_layer (gimage, layer);

  /*  end the group undo  */
  gimp_image_undo_group_end (gimage);

  /*  invalidate the boundaries  */
  gimp_drawable_invalidate_boundary (GIMP_DRAWABLE (gimp_image_get_mask (gimage)));
}

void
floating_sel_activate_drawable (GimpLayer *layer)
{
  GimpImage *gimage;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  gimage = gimp_item_get_image (GIMP_ITEM (layer));

  /*  set the underlying drawable to active  */
  if (GIMP_IS_LAYER_MASK (layer->fs.drawable))
    {
      GimpLayerMask *mask = GIMP_LAYER_MASK (layer->fs.drawable);

      gimp_image_set_active_layer (gimage, gimp_layer_mask_get_layer (mask));
    }
  else if (GIMP_IS_CHANNEL (layer->fs.drawable))
    {
      gimp_image_set_active_channel (gimage, GIMP_CHANNEL (layer->fs.drawable));
    }
  else
    {
      gimp_image_set_active_layer (gimage, GIMP_LAYER (layer->fs.drawable));
    }
}

void
floating_sel_to_layer (GimpLayer *layer)
{
  GimpItem  *item;
  GimpImage *gimage;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  item = GIMP_ITEM (layer);

  if (! (gimage = gimp_item_get_image (item)))
    return;

  /*  Check if the floating layer belongs to a channel...  */
  if (GIMP_IS_CHANNEL (layer->fs.drawable))
    {
      g_message (_("Cannot create a new layer from the floating selection "
		   "because it belongs to a layer mask or channel."));
      return;
    }

  gimp_image_undo_group_start (gimage, GIMP_UNDO_GROUP_FS_TO_LAYER,
                               _("Floating Selection to Layer"));

  /*  restore the contents of the drawable  */
  floating_sel_restore (layer,
			item->offset_x,
			item->offset_y,
			item->width,
			item->height);

  gimp_image_undo_push_fs_to_layer (gimage, NULL,
                                    layer, layer->fs.drawable);

  /*  clear the selection  */
  gimp_drawable_invalidate_boundary (GIMP_DRAWABLE (layer));

  /*  Set pointers  */
  layer->fs.drawable   = NULL;
  gimage->floating_sel = NULL;
  gimp_item_set_visible (GIMP_ITEM (layer), TRUE, TRUE);

  gimp_image_undo_group_end (gimage);

  gimp_object_name_changed (GIMP_OBJECT (layer));

  gimp_drawable_update (GIMP_DRAWABLE (layer),
			0, 0,
			GIMP_ITEM (layer)->width,
			GIMP_ITEM (layer)->height);

  gimp_image_floating_selection_changed (gimage);
}

void
floating_sel_store (GimpLayer *layer,
		    gint       x,
		    gint       y,
		    gint       w,
		    gint       h)
{
  PixelRegion srcPR, destPR;
  gint        offx, offy;
  gint        x1, y1, x2, y2;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  /*  Check the backing store & make sure it has the correct dimensions  */
  if ((tile_manager_width  (layer->fs.backing_store) !=
       gimp_item_width (GIMP_ITEM(layer)))  ||
      (tile_manager_height (layer->fs.backing_store) !=
       gimp_item_height (GIMP_ITEM(layer))) ||
      (tile_manager_bpp    (layer->fs.backing_store) !=
       gimp_drawable_bytes (layer->fs.drawable)))
    {
      /*  free the backing store and allocate anew  */
      tile_manager_unref (layer->fs.backing_store);

      layer->fs.backing_store =
	tile_manager_new (GIMP_ITEM (layer)->width,
			  GIMP_ITEM (layer)->height,
			  gimp_drawable_bytes (layer->fs.drawable));
    }

  /*  What this function does is save the specified area of the
   *  drawable that this floating selection obscures.  We do this so
   *  that it will be possible to subsequently restore the drawable's area
   */
  gimp_item_offsets (GIMP_ITEM (layer->fs.drawable), &offx, &offy);

  /*  Find the minimum area we need to uncover -- in gimage space  */
  x1 = MAX (GIMP_ITEM (layer)->offset_x, offx);
  y1 = MAX (GIMP_ITEM (layer)->offset_y, offy);
  x2 = MIN (GIMP_ITEM (layer)->offset_x + GIMP_ITEM (layer)->width,
	    offx + gimp_item_width (GIMP_ITEM (layer->fs.drawable)));
  y2 = MIN (GIMP_ITEM (layer)->offset_y + GIMP_ITEM (layer)->height,
	    offy + gimp_item_height (GIMP_ITEM (layer->fs.drawable)));

  x1 = CLAMP (x, x1, x2);
  y1 = CLAMP (y, y1, y2);
  x2 = CLAMP (x + w, x1, x2);
  y2 = CLAMP (y + h, y1, y2);

  if ((x2 - x1) > 0 && (y2 - y1) > 0)
    {
      /*  Copy the area from the drawable to the backing store  */
      pixel_region_init (&srcPR, gimp_drawable_data (layer->fs.drawable),
			 (x1 - offx), (y1 - offy), (x2 - x1), (y2 - y1), FALSE);
      pixel_region_init (&destPR, layer->fs.backing_store,
			 (x1 - GIMP_ITEM (layer)->offset_x),
			 (y1 - GIMP_ITEM (layer)->offset_y),
			 (x2 - x1), (y2 - y1), TRUE);

      copy_region (&srcPR, &destPR);
    }
}

void
floating_sel_restore (GimpLayer *layer,
		      gint       x,
		      gint       y,
		      gint       w,
		      gint       h)
{
  PixelRegion srcPR, destPR;
  gint        offx, offy;
  gint        x1, y1, x2, y2;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  /*  What this function does is "uncover" the specified area in the
   *  drawable that this floating selection obscures.  We do this so
   *  that either the floating selection can be removed or it can be
   *  translated
   */

  /*  Find the minimum area we need to uncover -- in gimage space  */
  gimp_item_offsets (GIMP_ITEM (layer->fs.drawable), &offx, &offy);

  x1 = MAX (GIMP_ITEM (layer)->offset_x, offx);
  y1 = MAX (GIMP_ITEM (layer)->offset_y, offy);
  x2 = MIN (GIMP_ITEM (layer)->offset_x + GIMP_ITEM (layer)->width,
	    offx + gimp_item_width  (GIMP_ITEM (layer->fs.drawable)));
  y2 = MIN (GIMP_ITEM(layer)->offset_y + GIMP_ITEM (layer)->height,
	    offy + gimp_item_height (GIMP_ITEM (layer->fs.drawable)));

  x1 = CLAMP (x, x1, x2);
  y1 = CLAMP (y, y1, y2);
  x2 = CLAMP (x + w, x1, x2);
  y2 = CLAMP (y + h, y1, y2);

  if ((x2 - x1) > 0 && (y2 - y1) > 0)
    {
      /*  Copy the area from the backing store to the drawable  */
      pixel_region_init (&srcPR, layer->fs.backing_store,
			 (x1 - GIMP_ITEM (layer)->offset_x),
			 (y1 - GIMP_ITEM (layer)->offset_y),
			 (x2 - x1), (y2 - y1), FALSE);
      pixel_region_init (&destPR, gimp_drawable_data (layer->fs.drawable),
			 (x1 - offx), (y1 - offy), (x2 - x1), (y2 - y1), TRUE);

      copy_region (&srcPR, &destPR);
    }
}

void
floating_sel_rigor (GimpLayer *layer,
		    gboolean   push_undo)
{
  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  /*  store the affected area from the drawable in the backing store  */
  floating_sel_store (layer,
		      GIMP_ITEM (layer)->offset_x,
		      GIMP_ITEM (layer)->offset_y,
		      GIMP_ITEM (layer)->width,
		      GIMP_ITEM (layer)->height);
  layer->fs.initial = TRUE;

  if (push_undo)
    gimp_image_undo_push_fs_rigor (gimp_item_get_image (GIMP_ITEM (layer)),
                                   NULL,
                                   layer);
}

void
floating_sel_relax (GimpLayer *layer,
		    gboolean   push_undo)
{
  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  /*  restore the contents of drawable the floating layer is attached to  */
  if (layer->fs.initial == FALSE)
    floating_sel_restore (layer,
			  GIMP_ITEM (layer)->offset_x,
			  GIMP_ITEM (layer)->offset_y,
			  GIMP_ITEM (layer)->width,
			  GIMP_ITEM (layer)->height);
  layer->fs.initial = TRUE;

  if (push_undo)
    gimp_image_undo_push_fs_relax (gimp_item_get_image (GIMP_ITEM (layer)),
                                   NULL,
                                   layer);
}

void
floating_sel_composite (GimpLayer *layer,
			gint       x,
			gint       y,
			gint       w,
			gint       h,
			gboolean   push_undo)
{
  PixelRegion  fsPR;
  GimpImage   *gimage;
  GimpLayer   *d_layer = NULL;
  gint         preserve_trans;
  gint         active[MAX_CHANNELS];
  gint         offx, offy;
  gint         x1, y1, x2, y2;
  gint         i;

  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  if (! (gimage = gimp_item_get_image (GIMP_ITEM (layer))))
    return;

  /*  What this function does is composite the specified area of the
   *  drawble with the floating selection.  We do this when the gimage
   *  is constructed, before any other composition takes place.
   */

  /*  If this isn't the first composite,
   *  restore the image underneath
   */
  if (! layer->fs.initial)
    floating_sel_restore (layer, x, y, w, h);
  else if (gimp_item_get_visible (GIMP_ITEM (layer)))
    layer->fs.initial = FALSE;

  /*  First restore what's behind the image if necessary,
   *  then check for visibility
   */
  if (gimp_item_get_visible (GIMP_ITEM (layer)))
    {
      /*  Find the minimum area we need to composite -- in gimage space  */
      gimp_item_offsets (GIMP_ITEM (layer->fs.drawable), &offx, &offy);

      x1 = MAX (GIMP_ITEM (layer)->offset_x, offx);
      y1 = MAX (GIMP_ITEM (layer)->offset_y, offy);
      x2 = MIN (GIMP_ITEM (layer)->offset_x +
		GIMP_ITEM (layer)->width,
		offx + gimp_item_width  (GIMP_ITEM (layer->fs.drawable)));
      y2 = MIN (GIMP_ITEM (layer)->offset_y +
		GIMP_ITEM (layer)->height,
		offy + gimp_item_height (GIMP_ITEM (layer->fs.drawable)));

      x1 = CLAMP (x, x1, x2);
      y1 = CLAMP (y, y1, y2);
      x2 = CLAMP (x + w, x1, x2);
      y2 = CLAMP (y + h, y1, y2);

      if ((x2 - x1) > 0 && (y2 - y1) > 0)
	{
	  /*  composite the area from the layer to the drawable  */
	  pixel_region_init (&fsPR, GIMP_DRAWABLE (layer)->tiles,
			     (x1 - GIMP_ITEM (layer)->offset_x),
			     (y1 - GIMP_ITEM (layer)->offset_y),
			     (x2 - x1), (y2 - y1), FALSE);

	  /*  a kludge here to prevent the case of the drawable
	   *  underneath having preserve transparency on, and disallowing
	   *  the composited floating selection from being shown
	   */
	  if (GIMP_IS_LAYER (layer->fs.drawable))
	    {
	      d_layer = GIMP_LAYER (layer->fs.drawable);
	      if ((preserve_trans = gimp_layer_get_preserve_trans (d_layer)))
		gimp_layer_set_preserve_trans (d_layer, FALSE, FALSE);
	    }
	  else
	    preserve_trans = FALSE;

	  /*  We need to set all gimage channels to active to make sure that
	   *  nothing strange happens while applying the floating selection.
	   *  It wouldn't make sense for the floating selection to be affected
	   *  by the active gimage channels.
	   */
	  for (i = 0; i < MAX_CHANNELS; i++)
	    {
	      active[i] = gimage->active[i];
	      gimage->active[i] = 1;
	    }

	  /*  apply the fs with the undo specified by the value
	   *  passed to this function
	   */
	  gimp_drawable_apply_region (layer->fs.drawable, &fsPR,
                                      push_undo, NULL,
                                      layer->opacity,
                                      layer->mode,
                                      NULL,
                                      (x1 - offx), (y1 - offy));

	  /*  restore preserve transparency  */
	  if (preserve_trans)
	    gimp_layer_set_preserve_trans (d_layer, TRUE, FALSE);

	  /*  restore gimage active channels  */
	  for (i = 0; i < MAX_CHANNELS; i++)
	    gimage->active[i] = active[i];
	}
    }
}

const BoundSeg *
floating_sel_boundary (GimpLayer *layer,
		       gint      *n_segs)
{
  PixelRegion bPR;
  gint        i;

  g_return_val_if_fail (GIMP_IS_LAYER (layer), NULL);
  g_return_val_if_fail (gimp_layer_is_floating_sel (layer), NULL);
  g_return_val_if_fail (n_segs != NULL, NULL);

  if (layer->fs.boundary_known == FALSE)
    {
      if (layer->fs.segs)
	g_free (layer->fs.segs);

      /*  find the segments  */
      pixel_region_init (&bPR, GIMP_DRAWABLE (layer)->tiles,
			 0, 0,
			 GIMP_ITEM (layer)->width,
			 GIMP_ITEM (layer)->height, FALSE);
      layer->fs.segs = find_mask_boundary (&bPR, &layer->fs.num_segs,
					   WithinBounds, 0, 0,
					   GIMP_ITEM (layer)->width,
					   GIMP_ITEM (layer)->height,
                                           HALF_WAY);

      /*  offset the segments  */
      for (i = 0; i < layer->fs.num_segs; i++)
	{
	  layer->fs.segs[i].x1 += GIMP_ITEM (layer)->offset_x;
	  layer->fs.segs[i].y1 += GIMP_ITEM (layer)->offset_y;
	  layer->fs.segs[i].x2 += GIMP_ITEM (layer)->offset_x;
	  layer->fs.segs[i].y2 += GIMP_ITEM (layer)->offset_y;
	}

      layer->fs.boundary_known = TRUE;
    }

  *n_segs = layer->fs.num_segs;

  return layer->fs.segs;
}

void
floating_sel_invalidate (GimpLayer *layer)
{
  g_return_if_fail (GIMP_IS_LAYER (layer));
  g_return_if_fail (gimp_layer_is_floating_sel (layer));

  /*  Invalidate the attached-to drawable's preview  */
  gimp_viewable_invalidate_preview (GIMP_VIEWABLE (layer->fs.drawable));

  /*  Invalidate the boundary  */
  layer->fs.boundary_known = FALSE;
}