gimp/app/core/gimpimage-crop.c

/* 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 <string.h>

#include <glib-object.h>

#include "core-types.h"

#include "base/pixel-region.h"

#include "gimp.h"
#include "gimpchannel.h"
#include "gimpdrawable.h"
#include "gimpimage.h"
#include "gimpimage-crop.h"
#include "gimpimage-mask.h"
#include "gimpimage-projection.h"
#include "gimplayer.h"
#include "gimplayer-floating-sel.h"
#include "gimplist.h"

#include "undo.h"


typedef enum
{
  AUTO_CROP_NOTHING = 0,
  AUTO_CROP_ALPHA   = 1,
  AUTO_CROP_COLOR   = 2
} AutoCropType;


typedef guchar       * (* GetColorFunc)    (GObject     *crop_object,
					    gint         ,
					    gint         );
typedef AutoCropType   (* ColorsEqualFunc) (guchar      *,
					    guchar      *,
					    gint         );


/*  local function prototypes  */

static void           gimp_image_crop_adjust_guides (GimpImage    *gimage,
						     gint          x1,
						     gint          y1,
						     gint          x2,
						     gint          y2);

static AutoCropType   gimp_image_crop_guess_bgcolor (GObject      *get_color_obj,
						     GetColorFunc  get_color_func,
						     gint          bytes,
						     gboolean      has_alpha,
						     guchar       *color,
						     gint          x1, 
						     gint          x2, 
						     gint          y1, 
						     gint          y2);
static gint           gimp_image_crop_colors_equal  (guchar       *col1,
						     guchar       *col2,
						     gint          bytes);
static gint           gimp_image_crop_colors_alpha  (guchar       *col1,
						     guchar       *col2,
						     gint          bytes);


/*  public functions  */

void
gimp_image_crop (GimpImage *gimage,
		 gint       x1,
		 gint       y1,
		 gint       x2,
		 gint       y2,
		 gboolean   active_layer_only,
		 gboolean   crop_layers)
{
  GimpLayer   *layer;
  GimpLayer   *floating_layer;
  GimpChannel *channel;
  GList       *guide_list_ptr;
  GList       *list;
  gint         width, height;
  gint         lx1, ly1, lx2, ly2;
  gint         off_x, off_y;

  g_return_if_fail (gimage != NULL);
  g_return_if_fail (GIMP_IS_IMAGE (gimage));

  width  = x2 - x1;
  height = y2 - y1;

  /*  Make sure new width and height are non-zero  */
  if (width && height)
    {
      gimp_set_busy (gimage->gimp);

      if (active_layer_only)
	{
	  gint doff_x, doff_y;

	  layer = gimp_image_get_active_layer (gimage);

	  gimp_drawable_offsets (GIMP_DRAWABLE (layer), &doff_x, &doff_y);

	  off_x = (doff_x - x1);
	  off_y = (doff_y - y1);

          undo_push_group_start (gimage, LAYER_RESIZE_UNDO_GROUP);

	  if (gimp_layer_is_floating_sel (layer))
	    floating_sel_relax (layer, TRUE);

	  gimp_layer_resize (layer, width, height, off_x, off_y);

	  if (gimp_layer_is_floating_sel (layer))
	    floating_sel_rigor (layer, TRUE);

	  undo_push_group_end (gimage);
	}
      else
	{
	  floating_layer = gimp_image_floating_sel (gimage);

	  undo_push_group_start (gimage, IMAGE_CROP_UNDO_GROUP);

	  /*  relax the floating layer  */
	  if (floating_layer)
	    floating_sel_relax (floating_layer, TRUE);

	  /*  Push the image size to the stack  */
	  undo_push_image_size (gimage);

	  /*  Set the new width and height  */
	  gimage->width  = width;
	  gimage->height = height;

	  /*  Resize all channels  */
	  for (list = GIMP_LIST (gimage->channels)->list;
	       list;
	       list = g_list_next (list))
	    {
	      channel = (GimpChannel *) list->data;

	      gimp_channel_resize (channel, width, height, -x1, -y1);
	    }

	  /*  Don't forget the selection mask!  */
	  gimp_channel_resize (gimage->selection_mask, width, height, -x1, -y1);
	  gimp_image_mask_invalidate (gimage);

	  /*  crop all layers  */
	  list = GIMP_LIST (gimage->layers)->list;

	  while (list)
	    {
	      GList *next;

	      layer = (GimpLayer *) list->data;

	      next = g_list_next (list);

	      gimp_layer_translate (layer, -x1, -y1);

	      gimp_drawable_offsets (GIMP_DRAWABLE (layer), &off_x, &off_y);

	      if (crop_layers)
		{
		  gimp_drawable_offsets (GIMP_DRAWABLE (layer), &off_x, &off_y);

		  lx1 = CLAMP (off_x, 0, gimage->width);
		  ly1 = CLAMP (off_y, 0, gimage->height);
		  lx2 = CLAMP ((gimp_drawable_width (GIMP_DRAWABLE (layer)) + off_x),
			       0, gimage->width);
		  ly2 = CLAMP ((gimp_drawable_height (GIMP_DRAWABLE (layer)) + off_y),
			       0, gimage->height);
		  width = lx2 - lx1;
		  height = ly2 - ly1;

		  if (width && height)
		    gimp_layer_resize (layer, width, height,
				       -(lx1 - off_x),
				       -(ly1 - off_y));
		  else
		    gimp_image_remove_layer (gimage, layer);
		}

	      list = next;
	    }

	  /*  Make sure the projection matches the gimage size  */
	  gimp_image_projection_allocate (gimage);

	  /*  rigor the floating layer  */
	  if (floating_layer)
	    floating_sel_rigor (floating_layer, TRUE);

	  guide_list_ptr = gimage->guides;
	  while ( guide_list_ptr != NULL)
	    {
	      undo_push_image_guide (gimage, (GimpGuide *) guide_list_ptr->data);
	      guide_list_ptr = guide_list_ptr->next;
	    }
	  undo_push_group_end (gimage);
  
	  /* Adjust any guides we might have laying about */
	  gimp_image_crop_adjust_guides (gimage, x1, y1, x2, y2);
	}

      gimp_image_update (gimage,
                         0, 0,
                         gimage->width,
                         gimage->height);

      gimp_viewable_size_changed (GIMP_VIEWABLE (gimage));

      gimp_unset_busy (gimage->gimp);
    }
}

gboolean
gimp_image_crop_auto_shrink (GimpImage *gimage,
			     gint       x1,
			     gint       y1,
			     gint       x2,
			     gint       y2,
			     gboolean   active_drawable_only,
			     gint      *shrunk_x1,
			     gint      *shrunk_y1,
			     gint      *shrunk_x2,
			     gint      *shrunk_y2)
{
  GimpDrawable    *active_drawable = NULL;
  GetColorFunc     get_color_func;
  ColorsEqualFunc  colors_equal_func;
  GObject         *get_color_obj;
  guchar           bgcolor[MAX_CHANNELS] = { 0, 0, 0, 0 };
  gboolean         has_alpha;
  PixelRegion      PR;
  guchar          *buffer = NULL;
  gint             width, height;
  gint             bytes;
  gint             x, y, abort;
  gboolean         retval = FALSE;
  
  g_return_val_if_fail (gimage != NULL, FALSE);
  g_return_val_if_fail (GIMP_IS_IMAGE (gimage), FALSE);
  g_return_val_if_fail (shrunk_x1 != NULL, FALSE);
  g_return_val_if_fail (shrunk_y1 != NULL, FALSE);
  g_return_val_if_fail (shrunk_x2 != NULL, FALSE);
  g_return_val_if_fail (shrunk_y2 != NULL, FALSE);

  gimp_set_busy (gimage->gimp);
 
  /* You should always keep in mind that crop->tx2 and crop->ty2 are the NOT the
     coordinates of the bottomright corner of the area to be cropped. They point 
     at the pixel located one to the right and one to the bottom.  
   */

  if (active_drawable_only)
    {
      active_drawable = gimp_image_active_drawable (gimage);

      if (! active_drawable)
	goto FINISH;

      bytes          = gimp_drawable_bytes (GIMP_DRAWABLE (active_drawable));
      has_alpha      = gimp_drawable_has_alpha (GIMP_DRAWABLE (active_drawable));
      get_color_obj  = G_OBJECT (active_drawable);
      get_color_func = (GetColorFunc) gimp_drawable_get_color_at;
    }
  else
    {
      has_alpha      = TRUE; 
      bytes          = gimp_image_projection_bytes (gimage);
      get_color_obj  = G_OBJECT (gimage);
      get_color_func = (GetColorFunc) gimp_image_projection_get_color_at;
   }

  switch (gimp_image_crop_guess_bgcolor (get_color_obj, get_color_func,
					 bytes, has_alpha, bgcolor,
					 x1, x2-1, y1, y2-1))
    {
    case AUTO_CROP_ALPHA:
      colors_equal_func = (ColorsEqualFunc) gimp_image_crop_colors_alpha;
      break;
    case AUTO_CROP_COLOR:
      colors_equal_func = (ColorsEqualFunc) gimp_image_crop_colors_equal;
      break;
    default:
      goto FINISH;
      break;
    }

  width  = x2 - x1;
  height = y2 - y1;

  if (active_drawable_only)
    pixel_region_init (&PR, gimp_drawable_data (active_drawable), 
		       x1, y1, width, height, FALSE);
  else
    pixel_region_init (&PR, gimp_image_projection (gimage), 
		       x1, y1, width, height, FALSE);

  /* The following could be optimized further by processing
   * the smaller side first instead of defaulting to width    --Sven
   */

  buffer = g_malloc ((width > height ? width : height) * bytes);

  /* Check how many of the top lines are uniform/transparent. */
  abort = FALSE;
  for (y = y1; y < y2 && !abort; y++)
    {
      pixel_region_get_row (&PR, x1, y, width, buffer, 1);
      for (x = 0; x < width && !abort; x++)
	abort = !(colors_equal_func) (bgcolor, buffer + x * bytes, bytes);
    }
  if (y == y2 && !abort)
    goto FINISH;
  y1 = y - 1;

  /* Check how many of the bottom lines are uniform/transparent. */
  abort = FALSE;
  for (y = y2; y > y1 && !abort; y--)
    {
      pixel_region_get_row (&PR, x1, y-1 , width, buffer, 1);
      for (x = 0; x < width && !abort; x++)
	abort = !(colors_equal_func) (bgcolor, buffer + x * bytes, bytes);
    }
  y2 = y + 1;

  /* compute a new height for the next operations */
  height = y2 - y1;

  /* Check how many of the left lines are uniform/transparent. */
  abort = FALSE;
  for (x = x1; x < x2 && !abort; x++)
    {
      pixel_region_get_col (&PR, x, y1, height, buffer, 1);
      for (y = 0; y < height && !abort; y++)
	abort = !(colors_equal_func) (bgcolor, buffer + y * bytes, bytes);
    }
  x1 = x - 1;
 
  /* Check how many of the right lines are uniform/transparent. */
  abort = FALSE;
  for (x = x2; x > x1 && !abort; x--)
    {
      pixel_region_get_col (&PR, x-1, y1, height, buffer, 1);
      for (y = 0; y < height && !abort; y++)
	abort = !(colors_equal_func) (bgcolor, buffer + y * bytes, bytes);
    }
  x2 = x + 1;

  *shrunk_x1 = x1;
  *shrunk_y1 = y1;
  *shrunk_x2 = x2;
  *shrunk_y2 = y2;

  retval = TRUE;

 FINISH:
  g_free (buffer);
  gimp_unset_busy (gimage->gimp);

  return retval;
}


/*  private functions  */

static void
gimp_image_crop_adjust_guides (GimpImage *gimage,
			       gint       x1,
			       gint       y1,
			       gint       x2,
			       gint       y2)

{
  GList     *glist;
  GimpGuide *guide;
  gboolean   remove_guide;

  for (glist = gimage->guides; glist; glist = g_list_next (glist))
    {
      guide = (GimpGuide *) glist->data;

      remove_guide = FALSE;

      switch (guide->orientation)
	{
	case ORIENTATION_HORIZONTAL:
	  if ((guide->position < y1) || (guide->position > y2))
	    remove_guide = TRUE;
	  break;

	case ORIENTATION_VERTICAL:
	  if ((guide->position < x1) || (guide->position > x2))
	    remove_guide = TRUE;
	  break;

	default:
	  break;
	}

      if (remove_guide)
	{
	  guide->position = -1;
          guide = NULL;
	}
      else
	{
	  if (guide->orientation == ORIENTATION_HORIZONTAL)
	    {
	      guide->position -= y1 ;
	    }
	  else
	    {
	      guide->position -= x1;
	    }
	}
    }
}

static AutoCropType
gimp_image_crop_guess_bgcolor (GObject      *get_color_obj,
			       GetColorFunc  get_color_func,
			       gint          bytes,
			       gboolean      has_alpha,
			       guchar       *color,
			       gint          x1, 
			       gint          x2, 
			       gint          y1, 
			       gint          y2) 
{
  guchar *tl = NULL;
  guchar *tr = NULL;
  guchar *bl = NULL;
  guchar *br = NULL;
  gint    i, alpha;

  for (i = 0; i < bytes; i++)
    color[i] = 0; 

  /* First check if there's transparency to crop. If not, guess the 
   * background-color to see if at least 2 corners are equal.
   */

  if (!(tl = (*get_color_func) (get_color_obj, x1, y1))) 
    goto ERROR;
  if (!(tr = (*get_color_func) (get_color_obj, x1, y2))) 
    goto ERROR;
  if (!(bl = (*get_color_func) (get_color_obj, x2, y1))) 
    goto ERROR;  
  if (!(br = (*get_color_func) (get_color_obj, x2, y2))) 
    goto ERROR;

  if (has_alpha)
    {
      alpha = bytes - 1;
      if ((tl[alpha] == 0 && tr[alpha] == 0) ||
	  (tl[alpha] == 0 && bl[alpha] == 0) ||
	  (tr[alpha] == 0 && br[alpha] == 0) ||
	  (bl[alpha] == 0 && br[alpha] == 0))
	{
	  g_free (tl);
	  g_free (tr);
	  g_free (bl);
	  g_free (br);
	  return AUTO_CROP_ALPHA;
	}
    }
  
  if (gimp_image_crop_colors_equal (tl, tr, bytes) ||
      gimp_image_crop_colors_equal (tl, bl, bytes))
    {
      memcpy (color, tl, bytes);
    }
  else if (gimp_image_crop_colors_equal (br, bl, bytes) ||
	   gimp_image_crop_colors_equal (br, tr, bytes))
    {
      memcpy (color, br, bytes);
    }
  else
    {
      goto ERROR;
    }

  g_free (tl); 
  g_free (tr); 
  g_free (bl); 
  g_free (br);
  return AUTO_CROP_COLOR;

 ERROR:
  g_free (tl); 
  g_free (tr); 
  g_free (bl); 
  g_free (br);
  return AUTO_CROP_NOTHING;
}

static int 
gimp_image_crop_colors_equal (guchar *col1, 
			      guchar *col2, 
			      gint    bytes) 
{
  gboolean equal = TRUE;
  gint     b;
  
  for (b = 0; b < bytes; b++)
    {
      if (col1[b] != col2[b])
	{
	  equal = FALSE;
	  break;
	}
    }

  return equal;
}

static gboolean
gimp_image_crop_colors_alpha (guchar *dummy, 
			      guchar *col, 
			      gint    bytes) 
{
  if (col[bytes-1] == 0)
    return TRUE;
  else
    return FALSE;
}