gimp/plug-ins/common/curve_bend.c

/* curve_bend plugin for the GIMP (tested with GIMP 1.1.17, requires gtk+ 1.2) */

/* 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.
 */

/* Revision history
 *  (2002/09/xx)  v1.1.18 mitch and gsr: clean interface
 *  (2000/02/16)  v1.1.17b hof: added spinbuttons for rotate entry
 *  (2000/02/16)  v1.1.17 hof: undo bugfix (#6012)
 *                             don't call gimp_undo_push_group_end 
 *                             after gimp_displays_flush
 *  (1999/09/13)  v1.01  hof: PDB-calls updated for gimp 1.1.9
 *  (1999/05/10)  v1.0   hof: first public release
 *  (1999/04/23)  v0.0   hof: coding started,
 *                            splines and dialog parts are similar to curves.c
 */

#include "config.h"
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef __GNUC__
#warning GTK_DISABLE_DEPRECATED
#endif
#undef GTK_DISABLE_DEPRECATED

#include <gtk/gtk.h>

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

#include "libgimp/stdplugins-intl.h"


/* Defines */
#define PLUG_IN_NAME        "plug_in_curve_bend"
#define PLUG_IN_VERSION     "v1.1.17 (2000/02/16)"
#define PLUG_IN_IMAGE_TYPES "RGB*, GRAY*"
#define PLUG_IN_AUTHOR      "Wolfgang Hofer (hof@hotbot.com)"
#define PLUG_IN_COPYRIGHT   "Wolfgang Hofer"
#define PLUG_IN_DESCRIPTION "Bends a layer using 2 spline-curves"

#define PLUG_IN_ITER_NAME       "plug_in_curve_bend_Iterator"
#define PLUG_IN_DATA_ITER_FROM  "plug_in_curve_bend_ITER_FROM"
#define PLUG_IN_DATA_ITER_TO    "plug_in_curve_bend_ITER_TO"

#define KEY_POINTFILE "POINTFILE_CURVE_BEND"
#define KEY_POINTS    "POINTS"
#define KEY_VAL_Y     "VAL_Y"

#define MIDDLE 127

#define SIGNED_ROUND(x)  ((int) (((x < 0) ? (x) - 0.5 : (x) + 0.5)  ))
#define MIX_CHANNEL(a, b, m)  (((a * m) + (b * (255 - m))) / 255)

#define UP_GRAPH              0x1
#define UP_XRANGE_TOP         0x2
#define UP_PREVIEW_EXPOSE     0x4
#define UP_PREVIEW            0x8
#define UP_DRAW               0x10
#define UP_ALL                0xFF

#define ENTRY_WIDTH      50
#define GRAPH_WIDTH      256
#define GRAPH_HEIGHT     256
#define PREVIEW_SIZE_X   256
#define PREVIEW_SIZE_Y   256
#define PV_IMG_WIDTH     128
#define PV_IMG_HEIGHT    128
#define RADIUS           3
#define MIN_DISTANCE     8
#define PREVIEW_BPP      3
#define PREVIEW_BG_GRAY1 108
#define PREVIEW_BG_GRAY2 156

#define SMOOTH       0
#define GFREE        1

#define RANGE_MASK  GDK_EXPOSURE_MASK | \
                    GDK_ENTER_NOTIFY_MASK

#define GRAPH_MASK  GDK_EXPOSURE_MASK | \
		    GDK_POINTER_MOTION_MASK | \
		    GDK_POINTER_MOTION_HINT_MASK | \
                    GDK_ENTER_NOTIFY_MASK | \
		    GDK_BUTTON_PRESS_MASK | \
		    GDK_BUTTON_RELEASE_MASK | \
		    GDK_BUTTON1_MOTION_MASK


#define OUTLINE_UPPER    0
#define OUTLINE_LOWER    1

typedef struct _BenderValues BenderValues;
struct _BenderValues
{
  guchar  curve[2][256];            /* for curve_type freehand mode   0   <= curve  <= 255 */
  gdouble points[2][17][2];         /* for curve_type smooth mode     0.0 <= points <= 1.0 */

  int            curve_type;

  gint           smoothing;
  gint           antialias;
  gint           work_on_copy;
  gdouble        rotation;
  
  
  gint32         total_steps;
  gdouble        current_step;
};


typedef struct _Curves Curves;

struct _Curves
{
  int x, y;    /*  coords for last mouse click  */
};

typedef struct _BenderDialog BenderDialog;

struct _BenderDialog
{
  GtkWidget *shell;
  GtkWidget *outline_menu;
  GtkWidget *pv_widget;
  GtkWidget *graph;
  GtkAdjustment *rotate_data;
  GdkPixmap *pixmap;
  GtkWidget *filesel;

  GimpDrawable *drawable;
  int        color;
  int        outline;
  gint       preview;

  int        grab_point;
  int        last;
  int        leftmost;
  int        rightmost;
  int        curve_type;
  gdouble    points[2][17][2];    /*  0.0 <= points    <= 1.0 */
  guchar     curve[2][256];       /*  0   <= curve     <= 255 */
  gint32    *curve_ptr[2];        /*  0   <= curve_ptr <= src_drawable_width 
				   *  both arrays are allocated dynamic,
				   *  depending on drawable width
				   */
  gint32     min2[2];
  gint32     max2[2];
  gint32     zero2[2];
    
  gint       show_progress;
  gint       smoothing;
  gint       antialias;
  gint       work_on_copy;
  gdouble    rotation;
  
  
  gint32     preview_image_id;
  gint32     preview_layer_id1;
  gint32     preview_layer_id2;
  
  BenderValues  *bval_from;
  BenderValues  *bval_to;
  BenderValues  *bval_curr;

  gint           run;
};

/* points Coords:
 *
 *  1.0 +----+----+----+----+ 
 *      |    .    |    |    | 
 *      +--.-+--.-+----+----+ 
 *      .    |    .    |    |  
 *  0.5 +----+----+-.--+----+ 
 *      |    |    |    .    . 
 *      +----+----+----+-.-.+ 
 *      |    |    |    |    | 
 *  0.0 +----+----+----+----+ 
 *      0.0      0.5       1.0
 *
 * curve Coords:
 *
 *      OUTLINE_UPPER                                       OUTLINE_LOWER
 *
 *  255 +----+----+----+----+                          255 +----+----+----+----+
 *      |    .    |    |    |  ---   max	           |	.    |    |    |  ---	max
 *      +--.-+--.-+----+----+			           +--.-+--.-+----+----+
 *      .    |    .    |    |			 zero ___  .	|    .    |    |                 
 *      +----+----+-.--+----+   		           +----+----+-.--+----+
 *      |    |    |    .    .  ---   zero      	           |	|    |    .    .  
 *      +----+----+----+-.-.+  ___   min	           +----+----+----+-.-.+  ___	min
 *      |    |    |    |    |			           |	|    |    |    |
 *    0 +----+----+----+----+			         0 +----+----+----+----+
 *      0                   255 		           0		       255
 */

typedef double CRMatrix[4][4];


/* p_buildmenu Structures */

typedef struct _MenuItem   MenuItem;

typedef void (*MenuItemCallback) (GtkWidget *widget,
				  gpointer   user_data);
struct _MenuItem
{
  gchar *label;
  gchar  unused_accelerator_key;
  gint   unused_accelerator_mods;
  MenuItemCallback callback;
  gpointer user_data;
  MenuItem *unused_subitems;
  GtkWidget *widget;
};

typedef struct
{
  GimpDrawable *drawable;
  GimpPixelRgn  pr;
  gint       x1;
  gint       y1;
  gint       x2;
  gint       y2;
  gint       index_alpha;   /* 0 == no alpha, 1 == GREYA, 3 == RGBA */
  gint       bpp;
  GimpTile     *tile;
  gint       tile_row;
  gint       tile_col;
  gint       tile_width;
  gint       tile_height;
  gint       tile_dirty;
  gint       shadow;
  gint32     seldeltax;
  gint32     seldeltay;
  gint32     tile_swapcount;   
} t_GDRW;

typedef struct
{
  gint32 y;
  guchar color[4];
} t_Last;


/*  curves action functions  */
static void  query (void);
static void  run   (gchar   *name,
		    gint     nparams,
		    GimpParam  *param,
		    gint    *nreturn_vals,
		    GimpParam **return_vals);

static BenderDialog *  bender_new_dialog              (GimpDrawable *);
static void            bender_update                  (BenderDialog *, int);
static void            bender_plot_curve              (BenderDialog *,
						       int, int, int, int,
						       gint32, gint32, gint);
static void            bender_calculate_curve         (BenderDialog *, gint32,
						       gint32, gint);
static void            bender_rotate_adj_callback     (GtkAdjustment *, gpointer);
static void            bender_upper_callback          (GtkWidget *, gpointer);
static void            bender_lower_callback          (GtkWidget *, gpointer);
static void            bender_smooth_callback         (GtkWidget *, gpointer);
static void            bender_free_callback           (GtkWidget *, gpointer);
static void            bender_reset_callback          (GtkWidget *, gpointer);
static void            bender_copy_callback           (GtkWidget *, gpointer);
static void            bender_copy_inv_callback       (GtkWidget *, gpointer);
static void            bender_swap_callback           (GtkWidget *, gpointer);
static void            bender_ok_callback             (GtkWidget *, gpointer);
static void            bender_cancel_callback         (GtkWidget *, gpointer);
static void            bender_smoothing_callback      (GtkWidget *, gpointer);
static void            bender_antialias_callback      (GtkWidget *, gpointer);
static void            bender_work_on_copy_callback   (GtkWidget *, gpointer);
static void            bender_preview_update          (GtkWidget *, gpointer);
static void            bender_preview_update_once     (GtkWidget *, gpointer);
static void            bender_load_callback           (GtkWidget *, gpointer);
static void            bender_save_callback           (GtkWidget *, gpointer);
static gint            bender_pv_widget_events        (GtkWidget *, GdkEvent *,
						       BenderDialog *);
static gint            bender_graph_events            (GtkWidget *, GdkEvent *,
						       BenderDialog *);
static void            bender_CR_compose              (CRMatrix, CRMatrix,
						       CRMatrix);
static void            bender_init_min_max            (BenderDialog *, gint32);
static BenderDialog *  do_dialog                      (GimpDrawable *);
GtkWidget           *  p_buildmenu                    (MenuItem *);
static void            p_init_gdrw                    (t_GDRW *gdrw, GimpDrawable *drawable, 
						       int dirty, int shadow);
static void            p_end_gdrw                     (t_GDRW *gdrw);
static gint32          p_main_bend                    (BenderDialog *, GimpDrawable *, gint);
static gint32          p_create_pv_image              (GimpDrawable *src_drawable, gint32 *layer_id);
static void            p_render_preview               (BenderDialog *cd, gint32 layer_id);
static void            p_get_pixel                    (t_GDRW *gdrw, 
						       gint32 x, gint32 y, guchar *pixel);
static void            p_put_pixel                    (t_GDRW *gdrw, 
						       gint32 x, gint32 y, guchar *pixel);
static void            p_put_mix_pixel                (t_GDRW *gdrw, 
						       gint32 x, gint32 y, guchar *color, 
						       gint32 nb_curvy, gint32 nb2_curvy, 
						       gint32 curvy);
static void            p_stretch_curves               (BenderDialog *cd, gint32 xmax, gint32 ymax);
static void            p_cd_to_bval                   (BenderDialog *cd, BenderValues *bval);
static void            p_cd_from_bval                 (BenderDialog *cd, BenderValues *bval);
static void            p_store_values                 (BenderDialog *cd);
static void            p_retrieve_values              (BenderDialog *cd);
static void            p_bender_calculate_iter_curve  (BenderDialog *cd, gint32 xmax, gint32 ymax);
static void            p_delta_gdouble                (double *val, double val_from, double val_to, 
						       gint32 total_steps, gdouble current_step);
static void            p_delta_gint32                 (gint32 *val, gint32 val_from, gint32 val_to, 
						       gint32 total_steps, gdouble current_step);
static void            p_copy_points                  (BenderDialog *cd, int outline, int xy,  
						       int argc, gdouble *floatarray);
static void            p_copy_yval                    (BenderDialog *cd, int outline,  
						       int argc, gint8 *int8array);
static int             p_save_pointfile               (BenderDialog *cd, const gchar *filename);


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

static CRMatrix CR_basis =
{
  { -0.5,  1.5, -1.5,  0.5 },
  {  1.0, -2.5,  2.0, -0.5 },
  { -0.5,  0.0,  0.5,  0.0 },
  {  0.0,  1.0,  0.0,  0.0 },
};

static MenuItem outline_items[] =
{
  { N_("Upper"), 0, 0, bender_upper_callback, NULL, NULL, NULL },
  { N_("Lower"), 0, 0, bender_lower_callback, NULL, NULL, NULL },
  { NULL, 0, 0, NULL, NULL, NULL, NULL }
};

static MenuItem curve_type_items[] =
{
  { N_("Smooth"), 0, 0, bender_smooth_callback, NULL, NULL, NULL },
  { N_("Free"), 0, 0, bender_free_callback, NULL, NULL, NULL },
  { NULL, 0, 0, NULL, NULL, NULL, NULL }
};

int gb_debug = FALSE;

/* Functions */
/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX PDB_STUFF XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */

/* ============================================================================
 * p_pdb_procedure_available
 *   if requested procedure is available in the PDB return the number of args
 *      (0 upto n) that are needed to call the procedure.
 *   if not available return -1
 * ============================================================================
 */

gint 
p_pdb_procedure_available (char *proc_name)
{    
  gint             l_nparams;
  gint             l_nreturn_vals;
  GimpPDBProcType  l_proc_type;
  gchar           *l_proc_blurb;
  gchar           *l_proc_help;
  gchar           *l_proc_author;
  gchar           *l_proc_copyright;
  gchar           *l_proc_date;
  GimpParamDef    *l_params;
  GimpParamDef    *l_return_vals;
  gint             l_rc;

  l_rc = 0;
  
  /* Query the gimp application's procedural database
   *  regarding a particular procedure.
   */
  if (gimp_procedural_db_proc_info (proc_name,
				    &l_proc_blurb,
				    &l_proc_help,
				    &l_proc_author,
				    &l_proc_copyright,
				    &l_proc_date,
				    &l_proc_type,
				    &l_nparams, &l_nreturn_vals,
				    &l_params, &l_return_vals))
  {
     /* procedure found in PDB */
     return (l_nparams);
  }

  printf("Warning: Procedure %s not found.\n", proc_name);
  return -1;
}	/* end p_pdb_procedure_available */


/* ============================================================================
 * p_gimp_rotate
 *  PDB call of 'gimp_rotate'
 * ============================================================================
 */

gint 
p_gimp_rotate (gint32  image_id, 
	       gint32  drawable_id, 
	       gint32  interpolation, 
	       gdouble angle_deg)
{
   static char     *l_rotate_proc = "gimp_rotate";
   GimpParam          *return_vals;
   int              nreturn_vals;
   gdouble          l_angle_rad;
   int              l_nparams;
   int              l_rc;

#ifdef ROTATE_OPTIMIZE
   static char     *l_rotate_proc2 = "plug_in_rotate";
   gint32 l_angle_step;

   if     (angle_deg == 90.0)  { l_angle_step = 1; }
   else if(angle_deg == 180.0) { l_angle_step = 2; }
   else if(angle_deg == 270.0) { l_angle_step = 3; }   
   else                        { l_angle_step = 0; }

   if(l_angle_step != 0)
   {
      l_nparams = p_pdb_procedure_available(l_rotate_proc2);
      if (l_nparams == 5)
      {
        /* use faster rotate plugin on multiples of 90 degrees */
        return_vals = gimp_run_procedure (l_rotate_proc2,
                                          &nreturn_vals,
			                  GIMP_PDB_INT32, GIMP_RUN_NONINTERACTIVE,
			                  GIMP_PDB_IMAGE, image_id,
                                          GIMP_PDB_DRAWABLE, drawable_id,
			                  GIMP_PDB_INT32, l_angle_step,
			                  GIMP_PDB_INT32, FALSE,         /* dont rotate the whole image */
                                          GIMP_PDB_END);
        if (return_vals[0].data.d_status == GIMP_PDB_SUCCESS)
        {
          return 0;
        }
      
      }
   
   }
#endif

   l_rc = -1;
   l_angle_rad = (angle_deg * G_PI) / 180.0;

   l_nparams = p_pdb_procedure_available(l_rotate_proc);
   if (l_nparams >= 0)
   {
         /* use the new Interface (Gimp 1.1 style)
          * (1.1 knows the image_id where the drawable belongs to)
          */
        return_vals = gimp_run_procedure (l_rotate_proc,
                                          &nreturn_vals,
                                          GIMP_PDB_DRAWABLE, drawable_id,
			                  GIMP_PDB_INT32, interpolation,
			                  GIMP_PDB_FLOAT, l_angle_rad,
                                          GIMP_PDB_END);
     if (return_vals[0].data.d_status == GIMP_PDB_SUCCESS)
     {
        l_rc = 0;
     }
     else
     {
       printf("Error: %s call failed %d\n", l_rotate_proc, (int)return_vals[0].data.d_status);
     }

     gimp_destroy_params (return_vals, nreturn_vals);
   }
   else
   {
      printf("Error: Procedure %s not found.\n",l_rotate_proc);
   }
   return (l_rc);

}  /* end p_gimp_rotate */

/* ============================================================================
 * p_gimp_edit_copy
 *   
 * ============================================================================
 */

gint32  
p_gimp_edit_copy (gint32 image_id, 
		  gint32 drawable_id)
{
   static char     *l_procname = "gimp_edit_copy";
   GimpParam          *return_vals;
   int              nreturn_vals;

   if (p_pdb_procedure_available(l_procname) >= 0)
   {
      return_vals = gimp_run_procedure (l_procname,
                                    &nreturn_vals,
                                    GIMP_PDB_DRAWABLE,  drawable_id,
                                    GIMP_PDB_END);
                                    
      if (return_vals[0].data.d_status == GIMP_PDB_SUCCESS)
      {
         gimp_destroy_params (return_vals, nreturn_vals);
         return 0;
      }
      printf("Error: PDB call of %s failed status:%d\n", l_procname, (int)return_vals[0].data.d_status);
   }

   return(-1);
}	/* end p_gimp_edit_copy */

/* ============================================================================
 * p_gimp_edit_paste
 *   
 * ============================================================================
 */

gint32  
p_gimp_edit_paste (gint32 image_id, 
		   gint32 drawable_id, 
		   gint32 paste_into)
{
   static char     *l_procname = "gimp_edit_paste";
   GimpParam          *return_vals;
   int              nreturn_vals;
   gint32           fsel_layer_id;

   if (p_pdb_procedure_available(l_procname) >= 0)
   {
      return_vals = gimp_run_procedure (l_procname,
                                    &nreturn_vals,
                                    GIMP_PDB_DRAWABLE,  drawable_id,
                                    GIMP_PDB_INT32,     paste_into,
                                    GIMP_PDB_END);
                                    
      if (return_vals[0].data.d_status == GIMP_PDB_SUCCESS)
      {
         fsel_layer_id = return_vals[1].data.d_layer;
         gimp_destroy_params (return_vals, nreturn_vals);
         return (fsel_layer_id);
      }
      printf("Error: PDB call of %s failed status:%d\n", l_procname, (int)return_vals[0].data.d_status);
   }

   return(-1);
}	/* end p_gimp_edit_paste */


/* ============================================================================
 * p_if_selection_float_it
 * ============================================================================
 */

gint32
p_if_selection_float_it (gint32 image_id, 
			 gint32 layer_id)
{
  gint32   l_sel_channel_id;
  gint32   l_layer_id;
  gint32   l_x1, l_x2, l_y1, l_y2;
  gint32   non_empty;

  l_layer_id = layer_id;
  if(!gimp_layer_is_floating_selection (layer_id)  )
  {
    /* check and see if we have a selection mask */
    l_sel_channel_id  = gimp_image_get_selection(image_id);     

    gimp_selection_bounds (image_id, &non_empty, &l_x1, &l_y1, &l_x2, &l_y2);
    
    if (non_empty && l_sel_channel_id >= 0)
    {
	/* selection is TRUE, make a layer (floating selection) from the selection  */
        p_gimp_edit_copy(image_id, layer_id);
	l_layer_id = p_gimp_edit_paste(image_id, layer_id, FALSE);

    }
  }

  return(l_layer_id);
}

/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX END_PDB_STUFF XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */

/*
 *    M      M    AAAAA    IIIIII    N     N
 *    M M  M M   A     A     II      NN    N
 *    M  M   M   AAAAAAA     II      N  N  N 
 *    M      M   A     A     II      N    NN
 *    M      M   A     A   IIIIII    N     N
 */

MAIN ()

static void 
query (void)
{
  static GimpParamDef args[] =
  {
    { GIMP_PDB_INT32,      "run_mode", "Interactive, non-interactive"},
    { GIMP_PDB_IMAGE,      "image", "Input image" },
    { GIMP_PDB_DRAWABLE,   "drawable", "Input drawable (must be a layer without layermask)"},
    { GIMP_PDB_FLOAT,      "rotation", "Direction {angle 0 to 360 degree } of the bend effect"},
    { GIMP_PDB_INT32,      "smoothing", "Smoothing { TRUE, FALSE }"},
    { GIMP_PDB_INT32,      "antialias", "Antialias { TRUE, FALSE }"},
    { GIMP_PDB_INT32,      "work_on_copy", "{ TRUE, FALSE } TRUE: copy the drawable and bend the copy"},
    { GIMP_PDB_INT32,      "curve_type", " { 0, 1 } 0 == smooth (use 17 points), 1 == freehand (use 256 val_y) "},
    { GIMP_PDB_INT32,      "argc_upper_point_x", "{2 <= argc <= 17} "},
    { GIMP_PDB_FLOATARRAY, "upper_point_x", "array of 17 x point_koords { 0.0 <= x <= 1.0 or -1 for unused point }"},
    { GIMP_PDB_INT32,      "argc_upper_point_y", "{2 <= argc <= 17} "},
    { GIMP_PDB_FLOATARRAY, "upper_point_y", "array of 17 y point_koords { 0.0 <= y <= 1.0 or -1 for unused point }"},
    { GIMP_PDB_INT32,      "argc_lower_point_x", "{2 <= argc <= 17} "},
    { GIMP_PDB_FLOATARRAY, "lower_point_x", "array of 17 x point_koords { 0.0 <= x <= 1.0 or -1 for unused point }"},
    { GIMP_PDB_INT32,      "argc_lower_point_y", "{2 <= argc <= 17} "},
    { GIMP_PDB_FLOATARRAY, "lower_point_y", "array of 17 y point_koords { 0.0 <= y <= 1.0 or -1 for unused point }"},
    { GIMP_PDB_INT32,      "argc_upper_val_y", "{ 256 } "},
    { GIMP_PDB_INT8ARRAY,  "upper_val_y",   "array of 256 y freehand koord { 0 <= y <= 255 }"},
    { GIMP_PDB_INT32,      "argc_lower_val_y", "{ 256 } "},
    { GIMP_PDB_INT8ARRAY,  "lower_val_y",   "array of 256 y freehand koord { 0 <= y <= 255 }"}
  };
  
  static GimpParamDef return_vals[] =
  {
    { GIMP_PDB_LAYER, "bent_layer", "the handled layer" }
  };

  static GimpParamDef args_iter[] =
  {
    { GIMP_PDB_INT32, "run_mode", "non-interactive" },
    { GIMP_PDB_INT32, "total_steps", "total number of steps (# of layers-1 to apply the related plug-in)" },
    { GIMP_PDB_FLOAT, "current_step", "current (for linear iterations this is the layerstack position, otherwise some value inbetween)" },
    { GIMP_PDB_INT32, "len_struct", "length of stored data structure with id is equal to the plug_in  proc_name" },
  };

  /* the actual installation of the bend plugin */
  gimp_install_procedure (PLUG_IN_NAME,
                          PLUG_IN_DESCRIPTION,
                          "This plug-in does bend the active layer "
			  "If there is a current selection it is copied to floating selection "
			  "and the curve_bend distortion is done on the floating selection. "
                          "If work_on_copy parameter is TRUE, the curve_bend distortion is done "
			  "on a copy of the active layer (or floating selection). "
                          "The upper and lower edges are bent in shape of 2 spline curves. "
                          "both (upper and lower) curves are determined by upto 17 points "
                          "or by 256 Y-Values if curve_type == 1 (freehand mode) "
                          "If rotation is not 0, the layer is rotated before "
                          "and rotated back after the bend operation. This enables "
                          "bending in other directions than vertical."
                          "bending usually changes the size of the handled layer."
                          "this plugin sets the offsets of the handled layer to keep its center at the same position"
                          ,
                          PLUG_IN_AUTHOR,
                          PLUG_IN_COPYRIGHT,
                          PLUG_IN_VERSION,
                          N_("<Image>/Filters/Distorts/CurveBend..."),
                          PLUG_IN_IMAGE_TYPES,
                          GIMP_PLUGIN,
                          G_N_ELEMENTS (args),
                          G_N_ELEMENTS (return_vals),
                          args,
                          return_vals);
 
   /* the installation of the Iterator extension for the bend plugin */
  gimp_install_procedure (PLUG_IN_ITER_NAME,
                          "This extension calculates the modified values for one iterationstep for the call of plug_in_curve_bend",
                          "",
                          PLUG_IN_AUTHOR,
                          PLUG_IN_COPYRIGHT,
                          PLUG_IN_VERSION,
                          NULL,    /* do not appear in menus */
                          NULL,
                          GIMP_EXTENSION,
                          G_N_ELEMENTS (args_iter), 0,
                          args_iter, NULL);
}

static void
run (char    *name,           /* name of plugin */
     int      nparams,        /* number of in-paramters */
     GimpParam  *param,          /* in-parameters */
     int     *nreturn_vals,   /* number of out-parameters */
     GimpParam **return_vals)    /* out-parameters */
{
  const gchar  *l_env;
  BenderDialog *cd;
  
  GimpDrawable *l_active_drawable = NULL;
  gint32    l_image_id = -1;
  gint32    l_layer_id = -1;
  gint32    l_layer_mask_id = -1;
  gint32    l_bent_layer_id = -1;
  
  /* Get the runmode from the in-parameters */
  GimpRunMode run_mode = param[0].data.d_int32;

  /* status variable, use it to check for errors in invocation usualy only
     during non-interactive calling */
  GimpPDBStatusType status = GIMP_PDB_SUCCESS;

  /*always return at least the status to the caller. */
  static GimpParam values[2];


  if (run_mode == GIMP_RUN_INTERACTIVE) {
    INIT_I18N_UI();
  } else {
    INIT_I18N();
  }

   cd = NULL;

  l_env = g_getenv("BEND_DEBUG");
  if(l_env != NULL)
  {
    if((*l_env != 'n') && (*l_env != 'N')) gb_debug = 1;
  }
  
  if(gb_debug) fprintf(stderr, "\n\nDEBUG: run %s\n", name);

  /* initialize the return of the status */
  values[0].type = GIMP_PDB_STATUS;
  values[0].data.d_status = status;
  values[1].type = GIMP_PDB_LAYER;
  values[1].data.d_int32 = -1;
  *nreturn_vals = 2;
  *return_vals = values;

  if (strcmp (name, PLUG_IN_ITER_NAME) == 0)
  {
     gint32  len_struct;
     gint32  total_steps;
     gdouble current_step;
     BenderValues   bval;                  /* current values while iterating */
     BenderValues   bval_from, bval_to;    /* start and end values */

        /* Iterator procedure for animated calls is usually called from
         * "plug_in_gap_layers_run_animfilter"
         * (always run noninteractive)
         */
        if ((run_mode == GIMP_RUN_NONINTERACTIVE) && (nparams == 4))
        {
          total_steps  =  param[1].data.d_int32;
          current_step =  param[2].data.d_float;
          len_struct   =  param[3].data.d_int32;

          if(len_struct == sizeof(bval))
          {
            /* get _FROM and _TO data, 
             * This data was stored by plug_in_gap_layers_run_animfilter
             */


               gimp_get_data(PLUG_IN_DATA_ITER_FROM, &bval_from); 
               gimp_get_data(PLUG_IN_DATA_ITER_TO,   &bval_to); 
	       bval = bval_from;
    
               p_delta_gdouble(&bval.rotation, bval_from.rotation, bval_to.rotation, total_steps, current_step);
               /* note: iteration of curve and points arrays would not give useful results.
                *       (there might be different number of points in the from/to bender values )
                *       the iteration is done later, (see p_bender_calculate_iter_curve)
                *       when the curve is calculated.
                */

               bval.total_steps = total_steps;
               bval.current_step = current_step;


               gimp_set_data(PLUG_IN_NAME, &bval, sizeof(bval));
          }
          else status = GIMP_PDB_CALLING_ERROR;
        }
        else status = GIMP_PDB_CALLING_ERROR;

        values[0].data.d_status = status;
        return;
  }




  /* get image and drawable */
  l_image_id = param[1].data.d_int32;
  l_layer_id = param[2].data.d_drawable;

  gimp_undo_push_group_start (l_image_id);
  
  if(!gimp_drawable_is_layer(l_layer_id))
  {
     gimp_message(_("CurveBend operates on layers only (but was called on channel or mask)"));
     printf("Passed drawable is no Layer\n");
     status = GIMP_PDB_EXECUTION_ERROR; 
  }
  /* check for layermask */
  l_layer_mask_id = gimp_layer_get_mask_id(l_layer_id);
  if(l_layer_mask_id >= 0)
  {
     /* apply the layermask
      *   some transitions (especially rotate) cant operate proper on
      *   layers with masks !
      */
      gimp_image_remove_layer_mask(l_image_id, l_layer_id, 0 /* 0==APPLY */ );
  }

  /* if there is a selection, make it the floating selection layer */
  l_active_drawable = gimp_drawable_get (p_if_selection_float_it(l_image_id, l_layer_id));


  /* how are we running today? */
  if(status == GIMP_PDB_SUCCESS)
  {
    /* how are we running today? */
    switch (run_mode)
     {
      case GIMP_RUN_INTERACTIVE:
        /* Possibly retrieve data from a previous run */
        /* gimp_get_data (PLUG_IN_NAME, &g_bndvals); */

        /* Get information from the dialog */
        cd = do_dialog(l_active_drawable);
        cd->show_progress = TRUE;
        break;

      case GIMP_RUN_NONINTERACTIVE:
        /* check to see if invoked with the correct number of parameters */
        if (nparams >= 20)
        {
           cd = g_new (BenderDialog, 1);
           cd->run = TRUE;
           cd->show_progress = FALSE;
           cd->drawable = l_active_drawable;

           cd->rotation      = (gdouble) param[3].data.d_float;
           cd->smoothing     = (gint) param[4].data.d_int32;
           cd->antialias     = (gint) param[5].data.d_int32;
           cd->work_on_copy  = (gint) param[6].data.d_int32;
           cd->curve_type    = (int)  param[7].data.d_int32;

           p_copy_points(cd, OUTLINE_UPPER, 0, (int)param[8].data.d_int32,  param[9].data.d_floatarray);
           p_copy_points(cd, OUTLINE_UPPER, 1, (int)param[10].data.d_int32,  param[11].data.d_floatarray);
           p_copy_points(cd, OUTLINE_LOWER, 0, (int)param[12].data.d_int32,  param[13].data.d_floatarray);
           p_copy_points(cd, OUTLINE_LOWER, 1, (int)param[14].data.d_int32,  param[15].data.d_floatarray);

           p_copy_yval(cd, OUTLINE_UPPER, (int)param[16].data.d_int32, param[17].data.d_int8array);
           p_copy_yval(cd, OUTLINE_UPPER, (int)param[18].data.d_int32, param[19].data.d_int8array);

        }
        else
        {
          status = GIMP_PDB_CALLING_ERROR;
        }

        break;

      case GIMP_RUN_WITH_LAST_VALS:
        cd = g_new (BenderDialog, 1);
        cd->run = TRUE;
        cd->show_progress = TRUE;
        cd->drawable = l_active_drawable;
        p_retrieve_values(cd);  /* Possibly retrieve data from a previous run */
        break;

      default:
        break;
    }
  }

  if (cd == NULL)
  {
    status = GIMP_PDB_EXECUTION_ERROR;
  }

  if (status == GIMP_PDB_SUCCESS)
  {
    /* Run the main function */

     if(cd->run)
     {
        l_bent_layer_id = p_main_bend(cd, cd->drawable, cd->work_on_copy);

	/* Store variable states for next run */
	if (run_mode == GIMP_RUN_INTERACTIVE)
	{
            p_store_values(cd);
	}     
    }
    else
    {
      status = GIMP_PDB_EXECUTION_ERROR;       /* dialog ended with cancel button */
    }

    gimp_undo_push_group_end (l_image_id);

    /* If run mode is interactive, flush displays, else (script) don't
       do it, as the screen updates would make the scripts slow */
    if (run_mode != GIMP_RUN_NONINTERACTIVE)
      gimp_displays_flush ();

  }
  else
  {
    gimp_undo_push_group_end (l_image_id);
  }
  values[0].data.d_status = status;
  values[1].data.d_int32 = l_bent_layer_id;   /* return the id of handled layer */

  if (gb_debug) 
    printf ("end run curve_bend plugin\n");
  
}	/* end run */


/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
/*  Last_VALUEs and ITERATOR stuff   */
/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
int
p_save_pointfile (BenderDialog *cd, 
		  const gchar  *filename)
{
  int j;
  FILE *l_fp;

  if(gb_debug) printf("Saving curve to file:%s\n", filename);

  l_fp = fopen(filename, "w+");
  if(l_fp == NULL)
  {
    return -1;
  }

  fprintf(l_fp, "%s\n", KEY_POINTFILE);
  fprintf(l_fp, "VERSION 1.0\n\n");

  fprintf(l_fp, "# points for upper and lower smooth curve (0.0 <= pt <= 1.0)\n");
  fprintf(l_fp, "# there are upto 17 points where unused points are set to -1\n");
  fprintf(l_fp, "#       UPPERX     UPPERY      LOWERX    LOWERY\n");
  fprintf(l_fp, "\n");

  for(j=0; j < 17; j++)
  {
      fprintf(l_fp, "%s %+.6f  %+.6f   %+.6f  %+.6f\n", KEY_POINTS,
                  (float)cd->points[OUTLINE_UPPER][j][0], 
                  (float)cd->points[OUTLINE_UPPER][j][1],
                  (float)cd->points[OUTLINE_LOWER][j][0], 
                  (float)cd->points[OUTLINE_LOWER][j][1] );
  }

  fprintf(l_fp, "\n");
  fprintf(l_fp, "# y values for upper/lower freehand curve (0 <= y <= 255) \n");
  fprintf(l_fp, "# there must be exactly 256 y values \n");
  fprintf(l_fp, "#     UPPER_Y  LOWER_Y\n");
  fprintf(l_fp, "\n");

  for(j=0; j < 256; j++)
  {
    fprintf(l_fp, "%s %3d  %3d\n", KEY_VAL_Y, 
               (int)cd->curve[OUTLINE_UPPER][j],
               (int)cd->curve[OUTLINE_LOWER][j]);
  }

  fclose(l_fp);
  return 0; /* OK */
}	/* end p_save_pointfile */


int
p_load_pointfile (BenderDialog *cd, 
		  const gchar  *filename)
{
  int   l_pi, l_ci, l_n, l_len;
  FILE *l_fp;
  char  l_buff[2000];
  float l_fux, l_fuy, l_flx, l_fly;
  int   l_iuy, l_ily ;
  
  if(gb_debug) printf("Loading curve from file:%s\n", filename);

  l_fp = fopen(filename, "r");
  if(l_fp == NULL)
  {
    return -1;
  }

  l_pi= 0;
  l_ci= 0;

  fgets (l_buff, 2000-1, l_fp);
  if(strncmp(l_buff, KEY_POINTFILE, strlen(KEY_POINTFILE)) == 0)
  {
     while (NULL != fgets (l_buff, 2000-1, l_fp))
     {
        if(gb_debug) printf("FGETS: %s\n", l_buff);
        l_len = strlen(KEY_POINTS);
        if(strncmp(l_buff, KEY_POINTS, l_len) == 0)
        {
           l_n = sscanf(&l_buff[l_len], "%f %f %f %f", &l_fux, &l_fuy, &l_flx, &l_fly);
           if((l_n == 4) && (l_pi < 17))
           {
             cd->points[OUTLINE_UPPER][l_pi][0] = l_fux;
             cd->points[OUTLINE_UPPER][l_pi][1] = l_fuy;
             cd->points[OUTLINE_LOWER][l_pi][0] = l_flx;
             cd->points[OUTLINE_LOWER][l_pi][1] = l_fly;
             if(gb_debug) printf("OK points[%d]\n", l_pi);     
             l_pi++;
           }
	   else
	   {
	      printf("warnig: BAD points[%d] in file %s are ignored\n", l_pi, filename);
	   }
        }
        l_len = strlen(KEY_VAL_Y);
        if(strncmp(l_buff, KEY_VAL_Y, l_len) == 0)
        {
           l_n = sscanf(&l_buff[l_len], "%d %d", &l_iuy, &l_ily);
           if((l_n == 2) && (l_ci < 256))
           {
             cd->curve[OUTLINE_UPPER][l_ci] = l_iuy;
             cd->curve[OUTLINE_LOWER][l_ci] = l_ily;
             l_ci++;
             if(gb_debug) printf("OK y_val[%d]\n", l_pi);     
           }
	   else
	   {
	      printf("warnig: BAD y_vals[%d] in file %s are ignored\n", l_ci, filename);
	   }
        }

     }
  }
  fclose(l_fp);
  return 0; /* OK */
}	/* end p_load_pointfile */



void
p_cd_to_bval (BenderDialog *cd, 
	      BenderValues *bval)
{
  int i,j;

  for(i=0; i<2; i++)
  {
    for(j=0; j<256; j++)
    {
      bval->curve[i][j] = cd->curve[i][j];
    }

    for(j=0; j<17; j++)
    {
      bval->points[i][j][0] = cd->points[i][j][0];  /* x */
      bval->points[i][j][1] = cd->points[i][j][1];  /* y */
    }
  }
  
  bval->curve_type = cd->curve_type;
  bval->smoothing = cd->smoothing;
  bval->antialias = cd->antialias;
  bval->work_on_copy = cd->work_on_copy;
  bval->rotation = cd->rotation;

  bval->total_steps = 0;
  bval->current_step =0.0;
}

void
p_cd_from_bval(BenderDialog *cd, BenderValues *bval)
{
  int i,j;

  for(i=0; i<2; i++)
  {
    for(j=0; j<256; j++)
    {
      cd->curve[i][j] = bval->curve[i][j];
    }

    for(j=0; j<17; j++)
    {
      cd->points[i][j][0] = bval->points[i][j][0];  /* x */
      cd->points[i][j][1] = bval->points[i][j][1];  /* y */
    }
  }
  
  cd->curve_type = bval->curve_type;
  cd->smoothing = bval->smoothing;
  cd->antialias = bval->antialias;
  cd->work_on_copy = bval->work_on_copy;
  cd->rotation = bval->rotation;

}

void
p_store_values (BenderDialog *cd)
{
  BenderValues l_bval;
  
  p_cd_to_bval(cd, &l_bval);
  gimp_set_data(PLUG_IN_NAME, &l_bval, sizeof(l_bval));
}

void
p_retrieve_values (BenderDialog *cd)
{
  BenderValues l_bval;

  l_bval.total_steps = 0;
  l_bval.current_step = -444.4;  /* init with an invalid  dummy value */
  
  gimp_get_data (PLUG_IN_NAME, &l_bval);

  if(l_bval.total_steps == 0)
  {
    cd->bval_from = NULL;
    cd->bval_to = NULL;
    if(l_bval.current_step != -444.4)
    {
       /* last_value data was retrieved (and dummy value was overwritten) */
       p_cd_from_bval(cd, &l_bval);
    }
  }
  else
  {
    cd->bval_from = g_new (BenderValues, 1);
    cd->bval_to   = g_new (BenderValues, 1);
    cd->bval_curr = g_new (BenderValues, 1);
    *cd->bval_curr = l_bval;
   
    /* it seems that we are called from GAP with "Varying Values" */
    gimp_get_data(PLUG_IN_DATA_ITER_FROM, cd->bval_from);
    gimp_get_data(PLUG_IN_DATA_ITER_TO,   cd->bval_to);
    *cd->bval_curr = l_bval;
    p_cd_from_bval(cd, cd->bval_curr);
    cd->work_on_copy = FALSE;
  }
}


static void 
p_delta_gdouble (double  *val, 
		 double   val_from, 
		 double   val_to, 
		 gint32   total_steps, 
		 gdouble  current_step)
{
    double     delta;

    if(total_steps < 1) return;

    delta = ((double)(val_to - val_from) / (double)total_steps) * ((double)total_steps - current_step);
    *val  = val_from + delta;
}

static void 
p_delta_gint32 (gint32  *val, 
		gint32   val_from, 
		gint32   val_to, 
		gint32   total_steps, 
		gdouble  current_step)
{
    double     delta;

    if(total_steps < 1) return;

    delta = ((double)(val_to - val_from) / (double)total_steps) * ((double)total_steps - current_step);
    *val  = val_from + delta;
}


void
p_copy_points (BenderDialog *cd, 
	       int           outline, 
	       int           xy, 
	       int           argc, 
	       gdouble      *floatarray)
{
   int j;
   
   for(j=0; j < 17; j++)
   {
     cd->points[outline][j][xy] = -1;
   }
   for(j=0; j < argc; j++)
   {
     cd->points[outline][j][xy] = floatarray[j];
   }
}

void
p_copy_yval (BenderDialog *cd, 
	     int           outline, 
	     int           argc, 
	     gint8        *int8array)
{
   int j;
   guchar fill;
   
   fill = MIDDLE;
   for(j=0; j < 256; j++)
   {
     if(j < argc) 
     {
        fill = cd->curve[outline][j] = int8array[j];
     }
     else
     {
        cd->curve[outline][j] = fill;
     }
   }
}

/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
/*  curves machinery  */
/* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */

BenderDialog *
do_dialog (GimpDrawable *drawable)
{
  BenderDialog *cd;
  gint  i;

  /* Init GTK  */
  gimp_ui_init ("curve_bend", TRUE);

  /*  The curve_bend dialog  */
  cd = bender_new_dialog (drawable);

  /* create temporary image (with a small copy of drawable) for the preview */
  cd->preview_image_id = p_create_pv_image(drawable, &cd->preview_layer_id1);
  cd->preview_layer_id2 = -1;
  
  /* show the outline menu   */
  for (i = 0; i < 2; i++)
  {
       gtk_widget_set_sensitive( outline_items[i].widget, TRUE);
  }
  
  /* set the current selection */
  gtk_option_menu_set_history ( GTK_OPTION_MENU (cd->outline_menu), 0);

  if (!GTK_WIDGET_VISIBLE (cd->shell))
    gtk_widget_show (cd->shell);


  bender_update (cd, UP_GRAPH | UP_DRAW);

  gtk_main ();
  gdk_flush ();

  gimp_image_delete(cd->preview_image_id);
  cd->preview_image_id = -1;
  cd->preview_layer_id1 = -1;
  cd->preview_layer_id2 = -1;
  
  if(gb_debug) printf("do_dialog END\n");  
  return cd;
}


/**************************/
/*  Select Curves dialog  */
/**************************/

static BenderDialog *
bender_new_dialog (GimpDrawable *drawable)
{
  BenderDialog *cd;
  GtkWidget *main_hbox;
  GtkWidget *vbox;
  GtkWidget *hbox;
  GtkWidget *vbox2;
  GtkWidget *abox;
  GtkWidget *frame;
  GtkWidget *table;
  GtkWidget *toggle;
  GtkWidget *option_menu;
  GtkWidget *button;
  GtkWidget *spinbutton;
  GtkWidget *label;
  GtkWidget *separator;
  GtkObject *data;
  int i, j;

  cd = g_new (BenderDialog, 1);

  cd->preview = FALSE;
  cd->curve_type = SMOOTH;
  cd->pixmap = NULL;
  cd->filesel = NULL;
  cd->outline = OUTLINE_UPPER;
  cd->show_progress = FALSE;
  cd->smoothing = TRUE;
  cd->antialias = TRUE;
  cd->work_on_copy = FALSE;
  cd->rotation = 0.0;       /* vertical bend */

  cd->drawable = drawable;
  cd->color = gimp_drawable_is_rgb (cd->drawable->drawable_id);

  cd->run = FALSE;
  cd->bval_from = NULL;
  cd->bval_to = NULL;
  cd->bval_curr = NULL;

  for (i = 0; i < 2; i++)
    for (j = 0; j < 256; j++)
      cd->curve[i][j] = MIDDLE;

  cd->grab_point = -1;
  for (i = 0; i < 2; i++)
    {
      for (j = 0; j < 17; j++)
        {
	  cd->points[i][j][0] = -1;
	  cd->points[i][j][1] = -1;
        }
      cd->points[i][0][0] = 0.0;        /* x */
      cd->points[i][0][1] = 0.5;        /* y */
      cd->points[i][16][0] = 1.0;       /* x */
      cd->points[i][16][1] = 0.5;       /* y */
    }


  p_retrieve_values(cd);       /* Possibly retrieve data from a previous run */

  for (i = 0; i < 2; i++)
    outline_items [i].user_data = (gpointer) cd;
  for (i = 0; i < 2; i++)
    curve_type_items [i].user_data = (gpointer) cd;

  /*  The shell and main vbox  */
  cd->shell = gimp_dialog_new (_("Curve Bend"), "curve_bend",
			       gimp_standard_help_func, "filters/curve_bend.html",
			       GTK_WIN_POS_MOUSE,
			       FALSE, TRUE, FALSE,

			       GTK_STOCK_CANCEL, bender_cancel_callback,
			       cd, NULL, NULL, FALSE, TRUE,

			       GTK_STOCK_OK, bender_ok_callback,
			       cd, NULL, NULL, TRUE, FALSE,

			       NULL);

  /*  The main hbox  */
  main_hbox = gtk_hbox_new (FALSE, 6);
  gtk_container_set_border_width (GTK_CONTAINER (main_hbox), 6);
  gtk_container_add (GTK_CONTAINER (GTK_DIALOG (cd->shell)->vbox), main_hbox);
  gtk_widget_show (main_hbox);

  /* Left side column */
  vbox =  gtk_vbox_new (FALSE, 4);
  gtk_container_add (GTK_CONTAINER (main_hbox), vbox);
  gtk_widget_show (vbox);

  /* Preview area, top of column */
  frame = gtk_frame_new (_("Preview"));
  gtk_box_pack_start (GTK_BOX (vbox), frame, TRUE, TRUE, 0);
  gtk_widget_show (frame);

  vbox2 = gtk_vbox_new (FALSE, 4);
  gtk_container_set_border_width (GTK_CONTAINER (vbox2), 2);
  gtk_container_add (GTK_CONTAINER (frame), vbox2);
  gtk_widget_show (vbox2);

  abox = gtk_alignment_new (0.5, 0.5, 0.0, 0.0);
  gtk_box_pack_start (GTK_BOX (vbox2), abox, FALSE, FALSE, 0);
  gtk_widget_show (abox);

  /*  The range drawing area  */
  frame = gtk_frame_new (NULL);
  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
  gtk_container_add (GTK_CONTAINER (abox), frame);
  gtk_widget_show (frame);

  cd->pv_widget = gtk_preview_new (GTK_PREVIEW_COLOR);
  gtk_preview_size (GTK_PREVIEW (cd->pv_widget), PREVIEW_SIZE_X, PREVIEW_SIZE_Y);
  gtk_widget_set_events (cd->pv_widget, RANGE_MASK);
  gtk_container_add (GTK_CONTAINER (frame), cd->pv_widget);
  gtk_widget_show (cd->pv_widget);

  g_signal_connect (cd->pv_widget, "event",
                    G_CALLBACK (bender_pv_widget_events),
                    cd);

  hbox = gtk_hbox_new (FALSE, 4);
  gtk_box_pack_end (GTK_BOX (vbox2), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  /*  The preview button  */
  button = gtk_button_new_with_mnemonic (_("_Preview Once"));
  gtk_box_pack_start (GTK_BOX (hbox), button, FALSE, FALSE, 0);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_preview_update_once),
                    cd);

  /*  The preview toggle  */
  toggle = gtk_check_button_new_with_mnemonic (_("Automatic Pre_view"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), cd->preview);
  gtk_box_pack_start (GTK_BOX (hbox), toggle, FALSE, FALSE, 0);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (bender_preview_update),
                    cd);

  /* Options area, bottom of column */
  frame = gtk_frame_new (_("Options"));
  gtk_box_pack_end (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
  gtk_widget_show (frame);

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

  /* Render Options  */
  hbox = gtk_hbox_new (FALSE, 4);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  /*  Rotate spinbutton  */
  label = gtk_label_new_with_mnemonic (_("R_otate:"));
  gtk_box_pack_start (GTK_BOX (hbox), label, FALSE, FALSE, 0);
  gtk_widget_show (label);

  spinbutton = gimp_spin_button_new (&data,
                                     0, 0.0, 360.0, 1, 45, 90,
                                     0.5, 1);
  cd->rotate_data = GTK_ADJUSTMENT (data);
  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 (cd->rotate_data, "value_changed",
                    G_CALLBACK (bender_rotate_adj_callback),
                    cd);

  /*  The smoothing toggle  */
  toggle = gtk_check_button_new_with_mnemonic (_("Sm_oothing"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), cd->smoothing);
  gtk_box_pack_start (GTK_BOX (vbox), toggle, FALSE, FALSE, 0);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (bender_smoothing_callback),
                    cd);

  /*  The antialiasing toggle  */
  toggle = gtk_check_button_new_with_mnemonic (_("_Antialiasing"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), cd->antialias);
  gtk_box_pack_start (GTK_BOX (vbox), toggle, FALSE, FALSE, 0);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (bender_antialias_callback),
                    cd);

  /*  The wor_on_copy toggle  */
  toggle = gtk_check_button_new_with_mnemonic (_("Work on Cop_y"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), cd->work_on_copy);
  gtk_box_pack_start (GTK_BOX (vbox), toggle, FALSE, FALSE, 0);
  gtk_widget_show (toggle);

  g_signal_connect (toggle, "toggled",
                    G_CALLBACK (bender_work_on_copy_callback),
                    cd);


  /*  The curves graph  */
  frame = gtk_frame_new (_("Modify Curves"));
  gtk_container_add (GTK_CONTAINER (main_hbox), frame);
  gtk_widget_show (frame);

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

  abox = gtk_alignment_new (0.5, 0.5, 0.0, 0.0);
  gtk_box_pack_start (GTK_BOX (vbox), abox, FALSE, FALSE, 0);
  gtk_widget_show (abox);

  cd->graph = gtk_drawing_area_new ();
  gtk_widget_set_size_request (cd->graph,
                               GRAPH_WIDTH + RADIUS * 2,
                               GRAPH_HEIGHT + RADIUS * 2);
  gtk_widget_set_events (cd->graph, GRAPH_MASK);
  gtk_container_add (GTK_CONTAINER (abox), cd->graph);
  gtk_widget_show (cd->graph);

  g_signal_connect (cd->graph, "event",
                    G_CALLBACK (bender_graph_events),
                    cd);

  table = gtk_table_new (3, 2, FALSE);
  gtk_table_set_row_spacings (GTK_TABLE (table), 2);
  gtk_table_set_col_spacings (GTK_TABLE (table), 4);
  gtk_box_pack_start (GTK_BOX (vbox), table, FALSE, FALSE, 0);
  gtk_widget_show (table);

  cd->outline_menu = gtk_option_menu_new ();
  gtk_option_menu_set_menu (GTK_OPTION_MENU (cd->outline_menu),
                            p_buildmenu (outline_items));
  gimp_table_attach_aligned (GTK_TABLE (table), 0, 0,
                             _("Curve for _Border:"), 1.0, 0.5,
                             cd->outline_menu, 1, TRUE);

  /*  The option menu for selecting the drawing method  */
  option_menu = gtk_option_menu_new ();
  gtk_option_menu_set_menu (GTK_OPTION_MENU (option_menu),
                            p_buildmenu (curve_type_items));
  gimp_table_attach_aligned (GTK_TABLE (table), 0, 1,
                             _("Curve _Type:"), 1.0, 0.5,
                             option_menu, 1, TRUE);


  /*  hbox for curve options  */
  hbox = gtk_hbox_new (FALSE, 4);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  /*  The Copy button  */
  button = gtk_button_new_with_mnemonic (_("_Copy"));
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);

  gimp_help_set_help_data (button,
                           _("Copy the active curve to the other border"), NULL);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_copy_callback),
                    cd);

  /*  The CopyInv button  */
  button = gtk_button_new_with_mnemonic (_("_Mirror"));
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);

  gimp_help_set_help_data (button,
                           _("Mirror the active curve to the other border"), NULL);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_copy_inv_callback),
                    cd);

  /*  The Swap button  */
  button = gtk_button_new_with_mnemonic (_("S_wap"));
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);

  gimp_help_set_help_data (button,
                           _("Swap the two curves"), NULL);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_swap_callback),
                    cd);

  /*  The Reset button  */
  button = gtk_button_new_from_stock (GIMP_STOCK_RESET);
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);

  gimp_help_set_help_data (button,
                           _("Reset the active curve"), NULL);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_reset_callback),
                    cd);

  /*  hbox for curve load and save  */
  hbox = gtk_hbox_new (FALSE, 4);
  gtk_box_pack_end (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  /*  The Load button  */
  button = gtk_button_new_from_stock (GTK_STOCK_OPEN);
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);

  gimp_help_set_help_data (button,
                           _("Load the curves from a file"), NULL);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_load_callback),
                    cd);

  /*  The Save button  */
  button = gtk_button_new_from_stock (GTK_STOCK_SAVE);
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);

  gimp_help_set_help_data (button,
                           _("Save the curves to a file"), NULL);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (bender_save_callback),
                    cd);

  /* Separate file ops from pure curve ops */
  separator = gtk_hseparator_new ();
  gtk_box_pack_end (GTK_BOX (vbox), separator, FALSE, FALSE, 0);
  gtk_widget_show (separator);

  gtk_widget_show (main_hbox);

  return cd;
}

static void
bender_update (BenderDialog *cd,
	       int           update)
{
  int i;
  int other;

  if (update & UP_PREVIEW)
    {
      if (cd->preview_layer_id2 >= 0)
         gimp_image_remove_layer(cd->preview_image_id, cd->preview_layer_id2);

      cd->preview_layer_id2 = p_main_bend(cd, gimp_drawable_get (cd->preview_layer_id1), TRUE /* work_on_copy*/ ); 
      p_render_preview(cd, cd->preview_layer_id2);
      
      if (update & UP_DRAW)
	gtk_widget_queue_draw (cd->pv_widget);
    }
  if (update & UP_PREVIEW_EXPOSE)
    {
      /* on expose just redraw cd->preview_layer_id2 
       * that holds the bent version of the preview (if there is one) 
       */
      if (cd->preview_layer_id2 < 0)
         cd->preview_layer_id2 = p_main_bend(cd, gimp_drawable_get (cd->preview_layer_id1), TRUE /* work_on_copy*/ ); 
      p_render_preview(cd, cd->preview_layer_id2);
      
      if (update & UP_DRAW)
	gtk_widget_queue_draw (cd->pv_widget);
    }
  if ((update & UP_GRAPH) && (update & UP_DRAW) && cd->pixmap != NULL)
    {
      GdkPoint points[256];

      /*  Clear the pixmap  */
      gdk_draw_rectangle (cd->pixmap, cd->graph->style->bg_gc[GTK_STATE_NORMAL],
			  TRUE, 0, 0, GRAPH_WIDTH + RADIUS * 2, GRAPH_HEIGHT + RADIUS * 2);

      /*  Draw the grid lines  */
      for (i = 0; i < 5; i++)
	{
	  gdk_draw_line (cd->pixmap, cd->graph->style->dark_gc[GTK_STATE_NORMAL],
			 RADIUS, i * (GRAPH_HEIGHT / 4) + RADIUS,
			 GRAPH_WIDTH + RADIUS, i * (GRAPH_HEIGHT / 4) + RADIUS);
	  gdk_draw_line (cd->pixmap, cd->graph->style->dark_gc[GTK_STATE_NORMAL],
			 i * (GRAPH_WIDTH / 4) + RADIUS, RADIUS,
			 i * (GRAPH_WIDTH / 4) + RADIUS, GRAPH_HEIGHT + RADIUS);
	}

      /*  Draw the other curve  */
      if(cd->outline == 0) { other = 1; }
      else                 { other = 0; }
      
      for (i = 0; i < 256; i++)
	{
	  points[i].x = i + RADIUS;
	  points[i].y = 255 - cd->curve[other][i] + RADIUS;
	}
      gdk_draw_points (cd->pixmap, cd->graph->style->dark_gc[GTK_STATE_NORMAL], points, 256);


      /*  Draw the active curve  */
      for (i = 0; i < 256; i++)
	{
	  points[i].x = i + RADIUS;
	  points[i].y = 255 - cd->curve[cd->outline][i] + RADIUS;
	}
      gdk_draw_points (cd->pixmap, cd->graph->style->black_gc, points, 256);

      /*  Draw the points  */
      if (cd->curve_type == SMOOTH)
	for (i = 0; i < 17; i++)
	  {
	    if (cd->points[cd->outline][i][0] != -1)
	      gdk_draw_arc (cd->pixmap, cd->graph->style->black_gc, TRUE,
			    (cd->points[cd->outline][i][0] * 255.0),
			    255 - (cd->points[cd->outline][i][1] * 255.0),
			    RADIUS * 2, RADIUS * 2, 0, 23040);
	  }


      gdk_draw_drawable (cd->graph->window, cd->graph->style->black_gc, cd->pixmap,
			 0, 0, 0, 0, GRAPH_WIDTH + RADIUS * 2, GRAPH_HEIGHT + RADIUS * 2);
    }
}


static void
bender_plot_curve (BenderDialog *cd,
		   int           p1,
		   int           p2,
		   int           p3,
		   int           p4,
		   gint32        xmax,
		   gint32        ymax,
		   gint          fix255)
{
  CRMatrix geometry;
  CRMatrix tmp1, tmp2;
  CRMatrix deltas;
  double x, dx, dx2, dx3;
  double y, dy, dy2, dy3;
  double d, d2, d3;
  int lastx, lasty;
  gint32 newx, newy;
  gint32 ntimes; 
  gint32 i;

  /* construct the geometry matrix from the segment */
  for (i = 0; i < 4; i++)
  {
      geometry[i][2] = 0;
      geometry[i][3] = 0;
  }

  geometry[0][0] = (cd->points[cd->outline][p1][0] * xmax);
  geometry[1][0] = (cd->points[cd->outline][p2][0] * xmax);
  geometry[2][0] = (cd->points[cd->outline][p3][0] * xmax);
  geometry[3][0] = (cd->points[cd->outline][p4][0] * xmax);

  geometry[0][1] = (cd->points[cd->outline][p1][1] * ymax);
  geometry[1][1] = (cd->points[cd->outline][p2][1] * ymax);
  geometry[2][1] = (cd->points[cd->outline][p3][1] * ymax);
  geometry[3][1] = (cd->points[cd->outline][p4][1] * ymax);

  /* subdivide the curve ntimes (1000) times */
  ntimes = 4 * xmax;
  /* ntimes can be adjusted to give a finer or coarser curve */
  d = 1.0 / ntimes;
  d2 = d * d;
  d3 = d * d * d;

  /* construct a temporary matrix for determining the forward differencing deltas */
  tmp2[0][0] = 0;     tmp2[0][1] = 0;     tmp2[0][2] = 0;    tmp2[0][3] = 1;
  tmp2[1][0] = d3;    tmp2[1][1] = d2;    tmp2[1][2] = d;    tmp2[1][3] = 0;
  tmp2[2][0] = 6*d3;  tmp2[2][1] = 2*d2;  tmp2[2][2] = 0;    tmp2[2][3] = 0;
  tmp2[3][0] = 6*d3;  tmp2[3][1] = 0;     tmp2[3][2] = 0;    tmp2[3][3] = 0;

  /* compose the basis and geometry matrices */
  bender_CR_compose (CR_basis, geometry, tmp1);

  /* compose the above results to get the deltas matrix */
  bender_CR_compose (tmp2, tmp1, deltas);

  /* extract the x deltas */
  x = deltas[0][0];
  dx = deltas[1][0];
  dx2 = deltas[2][0];
  dx3 = deltas[3][0];

  /* extract the y deltas */
  y = deltas[0][1];
  dy = deltas[1][1];
  dy2 = deltas[2][1];
  dy3 = deltas[3][1];

  lastx = CLAMP (x, 0, xmax);
  lasty = CLAMP (y, 0, ymax);


  if(fix255)
  {
    cd->curve[cd->outline][lastx] = lasty;
  }
  else  
  {
    cd->curve_ptr[cd->outline][lastx] = lasty;
    if(gb_debug) printf("bender_plot_curve xmax:%d ymax:%d\n", (int)xmax, (int)ymax);
  }

  /* loop over the curve */
  for (i = 0; i < ntimes; i++)
    {
      /* increment the x values */
      x += dx;
      dx += dx2;
      dx2 += dx3;

      /* increment the y values */
      y += dy;
      dy += dy2;
      dy2 += dy3;

      newx = CLAMP ((ROUND (x)), 0, xmax);
      newy = CLAMP ((ROUND (y)), 0, ymax);

      /* if this point is different than the last one...then draw it */
      if ((lastx != newx) || (lasty != newy))
      {
        if(fix255)
        {
          /* use fixed array size (for the curve graph) */
          cd->curve[cd->outline][newx] = newy;
	}
	else
	{
	  /* use dynamic allocated curve_ptr (for the real curve) */
	  cd->curve_ptr[cd->outline][newx] = newy;
	  
	  if(gb_debug) printf("outline: %d  cX: %d cY: %d\n", (int)cd->outline, (int)newx, (int)newy);	  
	}
      }

      lastx = newx;
      lasty = newy;
    }
}

static void
bender_calculate_curve (BenderDialog *cd, 
			gint32        xmax, 
			gint32        ymax, 
			gint          fix255)
{
  int i;
  int points[17];
  int num_pts;
  int p1, p2, p3, p4;
  int xmid;
  int yfirst, ylast;

  switch (cd->curve_type)
  {
    case GFREE:
      break;
    case SMOOTH:
      /*  cycle through the curves  */
      num_pts = 0;
      for (i = 0; i < 17; i++)
	if (cd->points[cd->outline][i][0] != -1)
	  points[num_pts++] = i;

      xmid = xmax / 2;
      /*  Initialize boundary curve points */
      if (num_pts != 0)
      {
        
        if(fix255)
        {
          for (i = 0; i < (cd->points[cd->outline][points[0]][0] * 255); i++)
	    cd->curve[cd->outline][i] = (cd->points[cd->outline][points[0]][1] * 255);
          for (i = (cd->points[cd->outline][points[num_pts - 1]][0] * 255); i < 256; i++)
	    cd->curve[cd->outline][i] = (cd->points[cd->outline][points[num_pts - 1]][1] * 255);
        }
        else
        {
	    yfirst  = cd->points[cd->outline][points[0]][1] * ymax;
	    ylast   = cd->points[cd->outline][points[num_pts - 1]][1] * ymax;
	    
	    for (i = 0; i < xmid; i++)
	    {
	       cd->curve_ptr[cd->outline][i] = yfirst;
	    }
	    for (i = xmid; i <= xmax; i++)
	    {
	       cd->curve_ptr[cd->outline][i] = ylast;
	    }
	      
        }
      }

      for (i = 0; i < num_pts - 1; i++)
      {
	  p1 = (i == 0) ? points[i] : points[(i - 1)];
	  p2 = points[i];
	  p3 = points[(i + 1)];
	  p4 = (i == (num_pts - 2)) ? points[(num_pts - 1)] : points[(i + 2)];

	  bender_plot_curve (cd, p1, p2, p3, p4, xmax, ymax, fix255);
      }
      break;
  }

}

static void
bender_rotate_adj_callback (GtkAdjustment *adjustment,
			      gpointer   client_data)
{
  BenderDialog *cd;
 
  cd = (BenderDialog *) client_data;

  if (adjustment->value != cd->rotation)
  {
    cd->rotation = adjustment->value;
    if(cd->preview) bender_update (cd, UP_PREVIEW | UP_DRAW);
  }
}


static void
bender_upper_callback (GtkWidget *w,
		       gpointer   client_data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) client_data;

  if (cd->outline != OUTLINE_UPPER)
    {
      cd->outline = OUTLINE_UPPER;
      bender_update (cd, UP_GRAPH | UP_DRAW);
    }
}

static void
bender_lower_callback (GtkWidget *w,
		       gpointer   client_data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) client_data;

  if (cd->outline != OUTLINE_LOWER)
    {
      cd->outline = OUTLINE_LOWER;
      bender_update (cd, UP_GRAPH | UP_DRAW);
    }
}


static void
bender_smooth_callback (GtkWidget *w,
			gpointer   client_data)
{
  BenderDialog *cd;
  int i;
  gint32 index;

  cd = (BenderDialog *) client_data;

  if (cd->curve_type != SMOOTH)
    {
      cd->curve_type = SMOOTH;

      /*  pick representative points from the curve and make them control points  */
      for (i = 0; i <= 8; i++)
	{
	  index = CLAMP ((i * 32), 0, 255);
	  cd->points[cd->outline][i * 2][0] = (gdouble)index / 255.0;
	  cd->points[cd->outline][i * 2][1] = (gdouble)cd->curve[cd->outline][index] / 255.0;
	}

      bender_calculate_curve (cd, 255, 255, TRUE);
      bender_update (cd, UP_GRAPH | UP_DRAW);

      if (cd->preview)
	bender_update (cd, UP_PREVIEW | UP_DRAW);
    }
}

static void
bender_free_callback (GtkWidget *w,
		      gpointer   client_data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) client_data;

  if (cd->curve_type != GFREE)
    {
      cd->curve_type = GFREE;
      bender_update (cd, UP_GRAPH | UP_DRAW);
    }
}

static void
bender_reset_callback (GtkWidget *widget,
		       gpointer   client_data)
{
  BenderDialog *cd;
  int i;

  cd = (BenderDialog *) client_data;

  /*  Initialize the values  */
  for (i = 0; i < 256; i++)
    cd->curve[cd->outline][i] = MIDDLE;

  cd->grab_point = -1;
  for (i = 0; i < 17; i++)
    {
      cd->points[cd->outline][i][0] = -1;
      cd->points[cd->outline][i][1] = -1;
    }
  cd->points[cd->outline][0][0] = 0.0;       /* x */
  cd->points[cd->outline][0][1] = 0.5;       /* y */
  cd->points[cd->outline][16][0] = 1.0;      /* x */
  cd->points[cd->outline][16][1] = 0.5;      /* y */

  bender_update (cd, UP_GRAPH | UP_DRAW);
  if (cd->preview)
    bender_update (cd, UP_PREVIEW | UP_DRAW);
}

static void
bender_copy_callback (GtkWidget *widget,
		      gpointer   client_data)
{
  BenderDialog *cd;
  int i;
  int other;

  cd = (BenderDialog *) client_data;

  if(cd->outline == 0)
     other = 1;
  else
     other = 0;


  for (i = 0; i < 17; i++)
    {
      cd->points[other][i][0] = cd->points[cd->outline][i][0];
      cd->points[other][i][1] = cd->points[cd->outline][i][1];
    }

  for (i= 0; i < 256; i++)
    {
      cd->curve[other][i] = cd->curve[cd->outline][i];
    }

  bender_update (cd, UP_GRAPH | UP_DRAW);
  if (cd->preview)
    bender_update (cd, UP_PREVIEW | UP_DRAW);
}

static void
bender_copy_inv_callback (GtkWidget *widget,
			  gpointer   client_data)
{
  BenderDialog *cd;
  int i;
  int other;

  cd = (BenderDialog *) client_data;

  if(cd->outline == 0)
     other = 1;
  else
     other = 0;


  for (i = 0; i < 17; i++)
    {
      cd->points[other][i][0] = cd->points[cd->outline][i][0];        /* x */
      cd->points[other][i][1] = 1.0 - cd->points[cd->outline][i][1];  /* y */
    }

  for (i= 0; i < 256; i++)
    {
      cd->curve[other][i] = 255 - cd->curve[cd->outline][i];
    }

  bender_update (cd, UP_GRAPH | UP_DRAW);
  if (cd->preview)
    bender_update (cd, UP_PREVIEW | UP_DRAW);
}


static void
bender_swap_callback (GtkWidget *widget,
		      gpointer   client_data)
{
#define SWAP_VALUE(a, b, h) { h=a; a=b; b=h; }
  BenderDialog *cd;
  int i;
  int other;
  gdouble hd;
  guchar  hu;

  cd = (BenderDialog *) client_data;

  if(cd->outline == 0)
     other = 1;
  else
     other = 0;


  for (i = 0; i < 17; i++)
    {
      SWAP_VALUE(cd->points[other][i][0], cd->points[cd->outline][i][0], hd);  /* x */    
      SWAP_VALUE(cd->points[other][i][1], cd->points[cd->outline][i][1], hd);  /* y */
    }

  for (i= 0; i < 256; i++)
    {
      SWAP_VALUE(cd->curve[other][i], cd->curve[cd->outline][i], hu);
    }

  bender_update (cd, UP_GRAPH | UP_DRAW);
  if (cd->preview)
    bender_update (cd, UP_PREVIEW | UP_DRAW);
}

static void
bender_ok_callback (GtkWidget *widget,
		    gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;

  if (GTK_WIDGET_VISIBLE (cd->shell))
    gtk_widget_hide (cd->shell);

  cd->run = TRUE;
  gtk_widget_destroy (GTK_WIDGET (cd->shell));
  gtk_main_quit ();
}

static void
bender_cancel_callback (GtkWidget *widget,
			gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;
  gtk_main_quit ();
}

static void
bender_preview_update (GtkWidget *widget,
		       gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;
  
  if (GTK_TOGGLE_BUTTON (widget)->active)
  {
      cd->preview = TRUE;
      bender_update (cd, UP_PREVIEW | UP_DRAW);
  }
  else
  {
    cd->preview = FALSE;
  }
}

static void
bender_preview_update_once (GtkWidget *widget,
			    gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;  
  bender_update (cd, UP_PREVIEW | UP_DRAW);
}

static void
p_filesel_close_cb (GtkWidget *widget,
		    gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;  

  if(gb_debug) printf("p_filesel_close_cb\n");

  if(cd->filesel == NULL) return;

  gtk_widget_destroy(GTK_WIDGET(cd->filesel));
  cd->filesel = NULL;   /* now filesel is closed */
}

static void
p_points_save_to_file (GtkWidget *widget,
		       gpointer	 data)
{
  BenderDialog *cd;
  const char   *filename;
 
  if(gb_debug) printf("p_points_save_to_file\n");
  cd = (BenderDialog *) data;  
  
  if(cd->filesel == NULL) return;
  
  filename = gtk_file_selection_get_filename(GTK_FILE_SELECTION (cd->filesel));
  p_save_pointfile(cd, filename);
  gtk_widget_destroy(GTK_WIDGET(cd->filesel));
  cd->filesel = NULL;
}

static void
p_points_load_from_file (GtkWidget *widget,
			 gpointer   data)
{
  BenderDialog *cd;
  const char   *filename;
 
  if(gb_debug) printf("p_points_load_from_file\n");
  cd = (BenderDialog *) data;  
  
  if(cd->filesel == NULL) return;
  
  filename = gtk_file_selection_get_filename(GTK_FILE_SELECTION (cd->filesel));
  p_load_pointfile(cd, filename);
  gtk_widget_destroy(GTK_WIDGET(cd->filesel));
  cd->filesel = NULL;
  bender_update (cd, UP_ALL);
}

static void
bender_load_callback (GtkWidget *w,
		      gpointer   data)
{
  BenderDialog *cd;
  GtkWidget *filesel;

  cd = (BenderDialog *) data;
  if(cd->filesel != NULL)
     return;   /* filesel is already open */
  
  filesel = gtk_file_selection_new ( _("Load Curve Points from file"));
  cd->filesel = filesel;
  
  gtk_window_set_position (GTK_WINDOW (filesel), GTK_WIN_POS_MOUSE);
  g_signal_connect (GTK_FILE_SELECTION (filesel)->ok_button,
                    "clicked",
                    G_CALLBACK (p_points_load_from_file),
                    cd);
  g_signal_connect (GTK_FILE_SELECTION (filesel)->cancel_button,
                    "clicked",
                    G_CALLBACK (p_filesel_close_cb),
                    cd);
  g_signal_connect (filesel, "destroy",
                    G_CALLBACK (p_filesel_close_cb),
                    cd);

  gtk_file_selection_set_filename (GTK_FILE_SELECTION (filesel),
				   "curve_bend.points");
  gtk_widget_show (filesel);

}

static void
bender_save_callback (GtkWidget *w,
		      gpointer   data)
{
  BenderDialog *cd;
  GtkWidget *filesel;

  cd = (BenderDialog *) data;
  if(cd->filesel != NULL)
     return;   /* filesel is already open */
  
  filesel = gtk_file_selection_new ( _("Save Curve Points to file"));
  cd->filesel = filesel;
  
  gtk_window_set_position (GTK_WINDOW (filesel), GTK_WIN_POS_MOUSE);
  g_signal_connect (GTK_FILE_SELECTION (filesel)->ok_button,
                    "clicked",
                    G_CALLBACK (p_points_save_to_file),
                    cd);
  g_signal_connect (GTK_FILE_SELECTION (filesel)->cancel_button,
                    "clicked",
                    G_CALLBACK (p_filesel_close_cb),
                    cd);
  g_signal_connect (filesel, "destroy",
		    G_CALLBACK (p_filesel_close_cb),
                    cd);

  gtk_file_selection_set_filename (GTK_FILE_SELECTION (filesel),
				   "curve_bend.points");
  gtk_widget_show (filesel);
}

static void
bender_smoothing_callback (GtkWidget *w,
		       gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;
  
  if (GTK_TOGGLE_BUTTON (w)->active) { cd->smoothing = TRUE;  }
  else                               { cd->smoothing = FALSE; }

  if(cd->preview) bender_update (cd, UP_PREVIEW | UP_DRAW);
}

static void
bender_antialias_callback (GtkWidget *w,
			   gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;
  
  if (GTK_TOGGLE_BUTTON (w)->active) { cd->antialias = TRUE; }
  else                               { cd->antialias = FALSE; }

  if(cd->preview) bender_update (cd, UP_PREVIEW | UP_DRAW);
}

static void
bender_work_on_copy_callback (GtkWidget *w,
			      gpointer   data)
{
  BenderDialog *cd;

  cd = (BenderDialog *) data;
  
  if (GTK_TOGGLE_BUTTON (w)->active) { cd->work_on_copy = TRUE;  }
  else                               { cd->work_on_copy = FALSE; }
}

static gint
bender_graph_events (GtkWidget    *widget,
		     GdkEvent     *event,
		     BenderDialog *cd)
{
  static GdkCursorType cursor_type = GDK_TOP_LEFT_ARROW;
  GdkCursorType new_type;
  GdkEventButton *bevent;
  GdkEventMotion *mevent;
  int i;
  int tx, ty;
  int x, y;
  int closest_point;
  int distance;
  int x1, x2, y1, y2;

  new_type      = GDK_X_CURSOR;
  closest_point = 0;

  /*  get the pointer position  */
  gdk_window_get_pointer (cd->graph->window, &tx, &ty, NULL);
  x = CLAMP ((tx - RADIUS), 0, 255);
  y = CLAMP ((ty - RADIUS), 0, 255);

  distance = G_MAXINT;
  for (i = 0; i < 17; i++)
    {
      if (cd->points[cd->outline][i][0] != -1)
	if (abs (x - (cd->points[cd->outline][i][0] * 255.0)) < distance)
	  {
	    distance = abs (x - (cd->points[cd->outline][i][0] * 255.0));
	    closest_point = i;
	  }
    }
  if (distance > MIN_DISTANCE)
    closest_point = (x + 8) / 16;

  switch (event->type)
    {
    case GDK_EXPOSE:
      if (cd->pixmap == NULL)
	cd->pixmap = gdk_pixmap_new (cd->graph->window,
				     GRAPH_WIDTH + RADIUS * 2,
				     GRAPH_HEIGHT + RADIUS * 2, -1);

      bender_update (cd, UP_GRAPH | UP_DRAW);
      break;

    case GDK_BUTTON_PRESS:
      bevent = (GdkEventButton *) event;
      new_type = GDK_TCROSS;

      switch (cd->curve_type)
	{
	case SMOOTH:
	  /*  determine the leftmost and rightmost points  */
	  cd->leftmost = -1;
	  for (i = closest_point - 1; i >= 0; i--)
	    if (cd->points[cd->outline][i][0] != -1)
	      {
		cd->leftmost = (cd->points[cd->outline][i][0] * 255.0);
		break;
	      }
	  cd->rightmost = 256;
	  for (i = closest_point + 1; i < 17; i++)
	    if (cd->points[cd->outline][i][0] != -1)
	      {
		cd->rightmost = (cd->points[cd->outline][i][0] * 255.0);
		break;
	      }

	  cd->grab_point = closest_point;
	  cd->points[cd->outline][cd->grab_point][0] = (gdouble)x / 255.0;
	  cd->points[cd->outline][cd->grab_point][1] = (gdouble)(255 - y) / 255.0;

	  bender_calculate_curve (cd, 255, 255, TRUE);
	  break;

	case GFREE:
	  cd->curve[cd->outline][x] = 255 - y;
	  cd->grab_point = x;
	  cd->last = y;
	  break;
	}

      bender_update (cd, UP_GRAPH | UP_DRAW);
      break;

    case GDK_BUTTON_RELEASE:
      new_type = GDK_FLEUR;
      cd->grab_point = -1;

      if (cd->preview)
	bender_update (cd, UP_PREVIEW | UP_DRAW);
      break;

    case GDK_MOTION_NOTIFY:
      mevent = (GdkEventMotion *) event;

      if (mevent->is_hint)
	{
	  mevent->x = tx;
	  mevent->y = ty;
	}

      switch (cd->curve_type)
	{
	case SMOOTH:
	  /*  If no point is grabbed...  */
	  if (cd->grab_point == -1)
	    {
	      if (cd->points[cd->outline][closest_point][0] != -1)
		new_type = GDK_FLEUR;
	      else
		new_type = GDK_TCROSS;
	    }
	  /*  Else, drag the grabbed point  */
	  else
	    {
	      new_type = GDK_TCROSS;

	      cd->points[cd->outline][cd->grab_point][0] = -1;

	      if (x > cd->leftmost && x < cd->rightmost)
		{
		  closest_point = (x + 8) / 16;
		  if (cd->points[cd->outline][closest_point][0] == -1)
		    cd->grab_point = closest_point;
		  cd->points[cd->outline][cd->grab_point][0] = (gdouble)x / 255.0;
		  cd->points[cd->outline][cd->grab_point][1] = (gdouble)(255 - y) / 255.0;
		}

	      bender_calculate_curve (cd, 255, 255, TRUE);
	      bender_update (cd, UP_GRAPH | UP_DRAW);
	    }
	  break;

	case GFREE:
	  if (cd->grab_point != -1)
	    {
	      if (cd->grab_point > x)
		{
		  x1 = x;
		  x2 = cd->grab_point;
		  y1 = y;
		  y2 = cd->last;
		}
	      else
		{
		  x1 = cd->grab_point;
		  x2 = x;
		  y1 = cd->last;
		  y2 = y;
		}

	      if (x2 != x1)
		for (i = x1; i <= x2; i++)
		  cd->curve[cd->outline][i] = 255 - (y1 + ((y2 - y1) * (i - x1)) / (x2 - x1));
	      else
		cd->curve[cd->outline][x] = 255 - y;

	      cd->grab_point = x;
	      cd->last = y;

	      bender_update (cd, UP_GRAPH | UP_DRAW);
	    }

	  if (mevent->state & GDK_BUTTON1_MASK)
	    new_type = GDK_TCROSS;
	  else
	    new_type = GDK_PENCIL;
	  break;
	}

      if (new_type != cursor_type)
	{
	  cursor_type = new_type;
	  /* change_win_cursor (cd->graph->window, cursor_type); */
	}
      break;

    default:
      break;
    }

  return FALSE;
}


static gint
bender_pv_widget_events (GtkWidget    *widget,
			 GdkEvent     *event,
			 BenderDialog *cd)
{
  switch (event->type)
    {
    case GDK_EXPOSE:
      bender_update (cd, UP_PREVIEW_EXPOSE);
      break;

    default:
      break;
    }

  return FALSE;
}

static void
bender_CR_compose (CRMatrix a,
		   CRMatrix b,
		   CRMatrix ab)
{
  int i, j;

  for (i = 0; i < 4; i++)
    {
      for (j = 0; j < 4; j++)
        {
          ab[i][j] = (a[i][0] * b[0][j] +
                      a[i][1] * b[1][j] +
                      a[i][2] * b[2][j] +
                      a[i][3] * b[3][j]);
        }
    }
}


/* ============================================================================
 * p_buildmenu
 *    build menu widget for all Items passed in the MenuItems Parameter
 *    MenuItems is an array of Pointers to Structure MenuItem.
 *    The End is marked by a Structure Member where the label is a NULL pointer
 *    (simplifyed version of GIMP 1.0.2 bulid_menu procedur)
 * ============================================================================
 */

GtkWidget *
p_buildmenu (MenuItem *items)
{
  GtkWidget *menu;
  GtkWidget *menu_item;

  menu = gtk_menu_new ();

  while (items->label)
    {
      menu_item = gtk_menu_item_new_with_label ( gettext(items->label));
      gtk_container_add (GTK_CONTAINER (menu), menu_item);

      if (items->callback)
	g_signal_connect (menu_item, "activate",
                          G_CALLBACK (items->callback),
                          items->user_data);

      gtk_widget_show (menu_item);
      items->widget = menu_item;

      items++;
    }

  return menu;
}	/* end p_buildmenu */

void
p_render_preview (BenderDialog *cd,
		  gint32        layer_id)
{
   guchar  l_rowbuf[PREVIEW_BPP * PREVIEW_SIZE_X];
   guchar  l_pixel[4];
   guchar *l_ptr;
   GimpDrawable *l_pv_drawable;
   gint    l_x, l_y;
   gint    l_ofx, l_ofy;
   gint    l_idx;
   guchar  l_bg_gray;
   t_GDRW  l_gdrw;
   t_GDRW  *gdrw;

   l_pv_drawable = gimp_drawable_get (layer_id);

   gdrw = &l_gdrw;
   p_init_gdrw(gdrw, l_pv_drawable, FALSE, FALSE);

  /* offsets to set bend layer to preview center */
  l_ofx = (l_pv_drawable->width / 2) - (PREVIEW_SIZE_X / 2);
  l_ofy = (l_pv_drawable->height / 2) - (PREVIEW_SIZE_Y / 2);
  
  /* render preview */
  for(l_y = 0; l_y < PREVIEW_SIZE_Y; l_y++)
  {
     l_ptr = &l_rowbuf[0];

     for(l_x = 0; l_x < PREVIEW_SIZE_X; l_x++)
     {
	p_get_pixel(gdrw, l_x + l_ofx, l_y + l_ofy, &l_pixel[0]);
	if(l_pixel[gdrw->index_alpha] < 255)
	{
	   /* for transparent pixels: mix with preview background color */
	   if((l_x % 32) < 16)
	   {
	      l_bg_gray = PREVIEW_BG_GRAY1;
	      if ((l_y % 32) < 16)   l_bg_gray = PREVIEW_BG_GRAY2;
	   }
	   else
	   {
	      l_bg_gray = PREVIEW_BG_GRAY2;
	      if ((l_y % 32) < 16)   l_bg_gray = PREVIEW_BG_GRAY1;
	   }
	   
	   for(l_idx = 0; l_idx < gdrw->index_alpha ; l_idx++)
	   {
	      l_pixel[l_idx] = MIX_CHANNEL(l_pixel[l_idx], l_bg_gray, l_pixel[gdrw->index_alpha]);
	   }
	}
	  
        
	if(cd->color)
	{
	  *l_ptr    = l_pixel[0];
	   l_ptr[1] = l_pixel[1];
	   l_ptr[2] = l_pixel[2];
	}
	else
	{
	  *l_ptr    = l_pixel[0];
	   l_ptr[1] = l_pixel[0];
	   l_ptr[2] = l_pixel[0];
        }

        l_ptr += PREVIEW_BPP;
     }

     gtk_preview_draw_row(GTK_PREVIEW(cd->pv_widget), &l_rowbuf[0], 0, l_y, PREVIEW_SIZE_X);
  }

   p_end_gdrw(gdrw);
}	/* end p_render_preview */

/* ===================================================== */
/* curve_bend worker procedures                          */
/* ===================================================== */

void
p_stretch_curves (BenderDialog *cd, 
		  gint32        xmax, 
		  gint32        ymax)
{
  gint32   l_x1, l_x2;
  gdouble  l_ya, l_yb;
  gdouble  l_rest;
  int      l_outline;

  for(l_outline = 0; l_outline < 2; l_outline++)
  {
    for(l_x1 = 0; l_x1 <= xmax; l_x1++)
    {
       l_x2 = (l_x1 * 255) / xmax;
       if((xmax <= 255) && (l_x2 < 255))
       {
         cd->curve_ptr[l_outline][l_x1] = ROUND((cd->curve[l_outline][l_x2] * ymax) / 255);
       }
       else
       {
         /* interpolate */
         l_rest = (((gdouble)l_x1 * 255.0) / (gdouble)xmax) - l_x2;
         l_ya = cd->curve[l_outline][l_x2];        /* y of this point */
         l_yb = cd->curve[l_outline][l_x2 +1];     /* y of next point */
         cd->curve_ptr[l_outline][l_x1] = ROUND (((l_ya + ((l_yb -l_ya) * l_rest)) * ymax) / 255);
       }

       {
        int      l_debugY;
        l_debugY = ROUND((cd->curve[l_outline][l_x2] * ymax) / 255);
/*
 *            printf("_X: %d  _X2: %d Y2: %d _Y: %d debugY:%d\n",
 *                   (int)l_x1, (int)l_x2,
 *                   (int)cd->curve[l_outline][l_x2],
 *                   (int)cd->curve_ptr[l_outline][l_x1], 
 *                   l_debugY);
 */
       }	  

    }
  }
}


void
bender_init_min_max (BenderDialog *cd, 
		     gint32        xmax)
{
  int i, j;

  for (i = 0; i < 2; i++)
  {
    cd->min2[i] = 65000;
    cd->max2[i] = 0;
    for (j = 0; j <= xmax; j++)
    {
       if(cd->curve_ptr[i][j] > cd->max2[i])
       {
          cd->max2[i] = cd->curve_ptr[i][j];
       }
       if(cd->curve_ptr[i][j] < cd->min2[i])
       {
          cd->min2[i] = cd->curve_ptr[i][j];
       }
    }
  }
  
  /* for UPPER outline : y-zero line is assumed at the min leftmost or rightmost point */
  cd->zero2[OUTLINE_UPPER] = MIN(cd->curve_ptr[OUTLINE_UPPER][0], cd->curve_ptr[OUTLINE_UPPER][xmax]);
 
  /* for LOWER outline : y-zero line is assumed at the min leftmost or rightmost point */
  cd->zero2[OUTLINE_LOWER] = MAX(cd->curve_ptr[OUTLINE_LOWER][0], cd->curve_ptr[OUTLINE_LOWER][xmax]);
  
  if(gb_debug)
  {
    printf("bender_init_min_max: zero2[0]: %d min2[0]:%d max2[0]:%d\n",
        (int)cd->zero2[0],
	(int)cd->min2[0],
	(int)cd->max2[0]  );
    printf("bender_init_min_max: zero2[1]: %d min2[1]:%d max2[1]:%d\n",
        (int)cd->zero2[1],
	(int)cd->min2[1],
	(int)cd->max2[1]  );
  }
	
}


gint32
p_curve_get_dy (BenderDialog *cd, 
		gint32        x, 
		gint32        drawable_width, 
		gint32        total_steps, 
		gdouble       current_step)
{
  /* get y values of both upper and lower curve,
   * and return the iterated value inbetween
   */
  gint32     l_y; 
  double     l_y1,  l_y2;
  double     delta;

  l_y1 = cd->zero2[OUTLINE_UPPER] - cd->curve_ptr[OUTLINE_UPPER][x];
  l_y2 = cd->zero2[OUTLINE_LOWER] - cd->curve_ptr[OUTLINE_LOWER][x];
  
  delta = ((double)(l_y2 - l_y1) / (double)(total_steps -1)) * current_step;
  l_y = SIGNED_ROUND(l_y1 + delta);
  
  return l_y;
}


gint32
p_upper_curve_extend (BenderDialog *cd, 
		      gint32        drawable_width, 
		      gint32        drawable_height)
{
   gint32  l_y1,  l_y2;
   
   l_y1 = cd->max2[OUTLINE_UPPER] - cd->zero2[OUTLINE_UPPER];
   l_y2 = (cd->max2[OUTLINE_LOWER] - cd->zero2[OUTLINE_LOWER]) - drawable_height;
   
   return (MAX(l_y1, l_y2));  
}

gint32
p_lower_curve_extend (BenderDialog *cd, 
		      gint32        drawable_width, 
		      gint32        drawable_height)
{
   gint32  l_y1,  l_y2;

   l_y1 = cd->zero2[OUTLINE_LOWER] - cd->min2[OUTLINE_LOWER];
   l_y2 = (cd->zero2[OUTLINE_UPPER] - cd->min2[OUTLINE_UPPER]) - drawable_height;

   return (MAX(l_y1, l_y2));  
}

void
p_end_gdrw (t_GDRW *gdrw)
{
  if(gb_debug)  
    printf ("\np_end_gdrw: drawable %p  ID: %d\n", 
	    gdrw->drawable, (int)gdrw->drawable->drawable_id);

  if(gdrw->tile)
  {
     if(gb_debug)  printf("p_end_gdrw: tile unref\n");
     gimp_tile_unref( gdrw->tile, gdrw->tile_dirty);
     gdrw->tile = NULL;
  }

  if(gb_debug)  
    printf("p_end_gdrw:TILE_SWAPCOUNT: %d\n", (int)gdrw->tile_swapcount);

}	/* end p_end_gdrw */


void
p_init_gdrw (t_GDRW    *gdrw, 
	     GimpDrawable *drawable, 
	     int        dirty, 
	     int        shadow)
{
  gint32 l_image_id;
  gint32 l_sel_channel_id;
  gint    l_offsetx, l_offsety;

  if(gb_debug)  printf("\np_init_gdrw: drawable %p  ID: %d\n", drawable, (int)drawable->drawable_id);

  gdrw->drawable = drawable;
  gdrw->tile = NULL;
  gdrw->tile_dirty = FALSE;
  gdrw->tile_width = gimp_tile_width ();
  gdrw->tile_height = gimp_tile_height ();
  gdrw->shadow = shadow;
  gdrw->tile_swapcount = 0;
  gdrw->seldeltax = 0;
  gdrw->seldeltay = 0;
  gimp_drawable_offsets (drawable->drawable_id, &l_offsetx, &l_offsety);  /* get offsets within the image */
  
  gimp_drawable_mask_bounds (drawable->drawable_id, &gdrw->x1, &gdrw->y1, &gdrw->x2, &gdrw->y2);

/*
 *   gimp_pixel_rgn_init (&gdrw->pr, drawable,
 *                       gdrw->x1, gdrw->y1, gdrw->x2 - gdrw->x1, gdrw->y2 - gdrw->y1,
 *                       dirty, shadow);
 */


  gdrw->bpp = drawable->bpp;
  if (gimp_drawable_has_alpha(drawable->drawable_id))
  {
     /* index of the alpha channelbyte {1|3} */
     gdrw->index_alpha = gdrw->bpp -1;
  }
  else
  {
     gdrw->index_alpha = 0;      /* there is no alpha channel */
  }
  
  if(gb_debug)  printf("\np_init_gdrw: bpp %d  index_alpha: %d\n", (int)gdrw->bpp, (int)gdrw->index_alpha);
  
  l_image_id = gimp_layer_get_image_id(drawable->drawable_id);

  /* check and see if we have a selection mask */
  l_sel_channel_id  = gimp_image_get_selection(l_image_id);     

  if(gb_debug)  
  {
     printf("p_init_gdrw: image_id %d sel_channel_id: %d\n", (int)l_image_id, (int)l_sel_channel_id);
     printf("p_init_gdrw: BOUNDS     x1: %d y1: %d x2:%d y2: %d\n",
        (int)gdrw->x1,  (int)gdrw->y1, (int)gdrw->x2,(int)gdrw->y2);
     printf("p_init_gdrw: OFFS       x: %d y: %d\n", (int)l_offsetx, (int)l_offsety );
  }
}	/* end p_init_gdrw */


static void
p_provide_tile (t_GDRW *gdrw, 
		gint    col, 
		gint    row, 
		gint    shadow )
{
    if ( col != gdrw->tile_col || row != gdrw->tile_row || !gdrw->tile )
    {
       if( gdrw->tile ) 
       {
	 gimp_tile_unref( gdrw->tile, gdrw->tile_dirty );
       }
       gdrw->tile_col = col;
       gdrw->tile_row = row;
       gdrw->tile = gimp_drawable_get_tile( gdrw->drawable, shadow, gdrw->tile_row, gdrw->tile_col );
       gdrw->tile_dirty = FALSE;
       gimp_tile_ref( gdrw->tile );

       gdrw->tile_swapcount++;

       return;
    }
}	/* end p_provide_tile */

/* get pixel value
 *   return light transparent black gray pixel if out of bounds
 *   (should occur in the previews only)
 */
static void
p_get_pixel (t_GDRW *gdrw, 
	     gint32  x, 
	     gint32  y, 
	     guchar *pixel )
{
    gint   row, col;
    gint   offx, offy;
    guchar  *ptr;

    if((x < 0)
    || (x > gdrw->drawable->width   -1)
    || (y < 0)
    || (y > gdrw->drawable->height - 1))
    {
      pixel[0] = pixel[1] = pixel[2] = pixel[3] = 0;
      return;
    }

    col = x / gdrw->tile_width;
    row = y / gdrw->tile_height;
    offx = x % gdrw->tile_width;
    offy = y % gdrw->tile_height;

    p_provide_tile(  gdrw, col, row, gdrw->shadow);

    pixel[1] = 255;  pixel[3] = 255;  /* simulate full visible alpha channel */
    ptr = gdrw->tile->data + ((( offy * gdrw->tile->ewidth) + offx ) * gdrw->bpp);
    memcpy(pixel, ptr, gdrw->bpp);

    /* printf("p_get_pixel: x: %d  y: %d bpp:%d RGBA:%d %d %d %d\n", (int)x, (int)y, (int)gdrw->bpp, (int)pixel[0], (int)pixel[1], (int)pixel[2], (int)pixel[3]);
     */
}	/* end p_get_pixel */

void
p_put_pixel (t_GDRW *gdrw, 
	     gint32  x, 
	     gint32  y, 
	     guchar *pixel)
{
    gint   row, col;
    gint   offx, offy;
    guchar  *ptr;

    if (x < gdrw->x1)       return;
    if (x > gdrw->x2 - 1)   return;
    if (y < gdrw->y1)       return;
    if (y > gdrw->y2 - 1)   return;

    col = x / gdrw->tile_width;
    row = y / gdrw->tile_height;
    offx = x % gdrw->tile_width;
    offy = y % gdrw->tile_height;

    p_provide_tile( gdrw, col, row, gdrw->shadow );

    ptr = gdrw->tile->data + ((( offy * gdrw->tile->ewidth ) + offx ) * gdrw->bpp);
    memcpy(ptr, pixel, gdrw->bpp);

    gdrw->tile_dirty = TRUE;

   /* printf("p_put_pixel: x: %d  y: %d shadow: %d bpp:%d RGBA:%d %d %d %d\n", (int)x, (int)y, (int)gdrw->shadow, (int)gdrw->bpp, (int)ptr[0], (int)ptr[1], (int)ptr[2], (int)ptr[3]);
    */
}	/* end p_put_pixel */

void
p_put_mix_pixel (t_GDRW *gdrw, 
		 gint32  x, 
		 gint32  y, 
		 guchar *color, 
		 gint32  nb_curvy, 
		 gint32  nb2_curvy, 
		 gint32  curvy)
{
   guchar  l_pixel[4];
   guchar  l_mixmask;
   gint    l_idx;
   gint    l_diff;
   
   l_mixmask = 255 - 96;
   l_diff = abs(nb_curvy - curvy);
   if(l_diff == 0)
   {
     l_mixmask = 255 - 48;
     l_diff = abs(nb2_curvy - curvy);
     
     if(l_diff == 0)
     {
       /* last 2 neighbours were not shifted against current pixel, do not mix */     
       p_put_pixel(gdrw, x, y, color);
       return;
     }
   }

   /* get left neighbour pixel */ 
   p_get_pixel(gdrw, x-1, y, &l_pixel[0]);

   if(l_pixel[gdrw->index_alpha] < 10)
   {
     /* neighbour is (nearly or full) transparent, do not mix */     
     p_put_pixel(gdrw, x, y, color);
     return;
   }

   for(l_idx = 0; l_idx < gdrw->index_alpha ; l_idx++)
   {
      /* mix in left neighbour color */
      l_pixel[l_idx] = MIX_CHANNEL(color[l_idx], l_pixel[l_idx], l_mixmask);
   }

   l_pixel[gdrw->index_alpha] = color[gdrw->index_alpha];
   p_put_pixel(gdrw, x, y, &l_pixel[0]);
}

void
p_put_mix_pixel_FIX (t_GDRW *gdrw, 
		     gint32  x, 
		     gint32  y, 
		     guchar *color, 
		     gint32  nb_curvy, 
		     gint32  nb2_curvy, 
		     gint32  curvy)
{
   guchar  l_pixel[4];
   guchar  l_mixmask;
   gint    l_idx;
   
   l_mixmask = 256 - 64;

   /* get left neighbour pixel */ 
   p_get_pixel(gdrw, x-1, y, &l_pixel[0]);

   if(l_pixel[gdrw->index_alpha] < 20)
   {
     /* neighbour is (nearly or full) transparent, do not mix */     
     p_put_pixel(gdrw, x, y, color);
     return;
   }

   for(l_idx = 0; l_idx < gdrw->index_alpha ; l_idx++)
   {
      /* mix in left neighbour color */
      l_pixel[l_idx] = MIX_CHANNEL(color[l_idx], l_pixel[l_idx], l_mixmask);
   }

   l_pixel[gdrw->index_alpha] = color[gdrw->index_alpha];
   p_put_pixel(gdrw, x, y, &l_pixel[0]);
}

/* ============================================================================
 * p_clear_drawable
 * ============================================================================
 */

void
p_clear_drawable (GimpDrawable *drawable)
{
   GimpPixelRgn  pixel_rgn;
   gpointer	pr;
   gint         l_row;
   guchar      *l_ptr;
   

   gimp_pixel_rgn_init (&pixel_rgn, drawable,
			     0, 0, drawable->width, drawable->height,
			     TRUE,  /* dirty */
			     FALSE  /* shadow */
			     );

   /* clear the drawable with 0 Bytes (black full-transparent pixels) */
   for (pr = gimp_pixel_rgns_register (1, &pixel_rgn);
	pr != NULL; pr = gimp_pixel_rgns_process (pr))
   {
      l_ptr = pixel_rgn.data;
      for ( l_row = 0; l_row < pixel_rgn.h; l_row++ )
      {
	memset(l_ptr, 0, pixel_rgn.w * drawable->bpp);
	l_ptr += pixel_rgn.rowstride;
      }
   }
}	/* end  p_clear_drawable */

/* ============================================================================
 * p_create_pv_image
 * ============================================================================
 */
gint32
p_create_pv_image (GimpDrawable *src_drawable, 
		   gint32    *layer_id)
{
  gint32     l_new_image_id;
  guint      l_new_width;
  guint      l_new_height;
  GimpImageType l_type;

  gint    l_x, l_y;
  double  l_scale;
  guchar  l_pixel[4];
  GimpDrawable *dst_drawable;
  t_GDRW  l_src_gdrw;
  t_GDRW  l_dst_gdrw;

  l_new_image_id = gimp_image_new(PREVIEW_SIZE_X, PREVIEW_SIZE_Y, 
                   gimp_image_base_type(gimp_layer_get_image_id(src_drawable->drawable_id)));
  gimp_image_undo_disable (l_new_image_id);

  l_type = gimp_drawable_type(src_drawable->drawable_id);  
  if(src_drawable->height > src_drawable->width)
  {
    l_new_height = PV_IMG_HEIGHT;
    l_new_width = (src_drawable->width * l_new_height) / src_drawable->height;
    l_scale = (float)src_drawable->height / PV_IMG_HEIGHT;
  }
  else
  {
    l_new_width = PV_IMG_WIDTH;
    l_new_height = (src_drawable->height * l_new_width) / src_drawable->width;
    l_scale = (float)src_drawable->width / PV_IMG_WIDTH;
  }

  *layer_id = gimp_layer_new(l_new_image_id, "preview_original",
                             l_new_width, l_new_height,
                             l_type, 
                             100.0,    /* opacity */
                             0         /* mode NORMAL */
                             );
  if(!gimp_drawable_has_alpha(*layer_id))
  {
    /* always add alpha channel */
    gimp_layer_add_alpha(*layer_id);
  }
                                 
  gimp_image_add_layer(l_new_image_id, *layer_id, 0);

  dst_drawable = gimp_drawable_get (*layer_id);
  p_init_gdrw(&l_src_gdrw, src_drawable, FALSE, FALSE);
  p_init_gdrw(&l_dst_gdrw, dst_drawable,  TRUE,  FALSE);

  for(l_y = 0; l_y < l_new_height; l_y++)
  {
     for(l_x = 0; l_x < l_new_width; l_x++)
     {
       p_get_pixel(&l_src_gdrw, l_x * l_scale, l_y * l_scale, &l_pixel[0]);
       p_put_pixel(&l_dst_gdrw, l_x, l_y, &l_pixel[0]);
     }
  }
  
  p_end_gdrw(&l_src_gdrw);
  p_end_gdrw(&l_dst_gdrw);

  /* gimp_display_new(l_new_image_id); */
  return (l_new_image_id);
}

/* ============================================================================
 * p_add_layer
 * ============================================================================
 */
GimpDrawable* 
p_add_layer (gint       width, 
	     gint       height, 
	     GimpDrawable *src_drawable)
{
  GimpImageType  l_type;
  static GimpDrawable  *l_new_drawable;
  gint32     l_new_layer_id;
  char      *l_name;
  char      *l_name2;
  gdouble    l_opacity;
  GimpLayerModeEffects l_mode;
  gint       l_visible;
  gint32     image_id;
  gint       stack_position;


  image_id = gimp_layer_get_image_id(src_drawable->drawable_id);
  stack_position = 0;                                  /* TODO:  should be same as src_layer */
  
  /* copy type, name, opacity and mode from src_drawable */ 
  l_type     = gimp_drawable_type(src_drawable->drawable_id);
  l_visible  = gimp_layer_get_visible(src_drawable->drawable_id);

  if (TRUE != TRUE)
  {
    l_name = gimp_layer_get_name(src_drawable->drawable_id);
  }
  else
  {
    l_name2 = gimp_layer_get_name(src_drawable->drawable_id);
    l_name  = g_malloc(strlen(l_name2) + 10);
    if(l_name == NULL) 
       return (NULL);
    sprintf(l_name, "%s_b", l_name2);
    g_free(l_name2);
  }
  l_mode = gimp_layer_get_mode(src_drawable->drawable_id);
  l_opacity = gimp_layer_get_opacity(src_drawable->drawable_id);  /* full opacity */
  
  l_new_layer_id = gimp_layer_new(image_id, l_name,
                                  width, height,
                                  l_type, 
                                  l_opacity,
                                  l_mode
                                  );

  if(l_name != NULL)         g_free (l_name);
  if(!gimp_drawable_has_alpha(l_new_layer_id))
  {
    /* always add alpha channel */
    gimp_layer_add_alpha(l_new_layer_id);
  }
  
  l_new_drawable = gimp_drawable_get (l_new_layer_id);
  if(l_new_drawable == NULL)
  {
     fprintf(stderr, "p_ad_layer: cant get new_drawable\n");
     return (NULL);
  }

  /* add the copied layer to the temp. working image */
  gimp_image_add_layer (image_id, l_new_layer_id, stack_position);

  /* copy visiblity state */
  gimp_layer_set_visible(l_new_layer_id, l_visible);
    
  return (l_new_drawable);
}

/* ============================================================================
 * p_bender_calculate_iter_curve
 * ============================================================================
 */


void
p_bender_calculate_iter_curve (BenderDialog *cd, 
			       gint32        xmax, 
			       gint32        ymax)
{
   int l_x;
   gint      l_outline;
   BenderDialog *cd_from;
   BenderDialog *cd_to;
 
   l_outline = cd->outline;
   
   if((cd->bval_from == NULL) || (cd->bval_to == NULL) || (cd->bval_curr == NULL))
   {
     if(gb_debug)  printf("p_bender_calculate_iter_curve NORMAL1\n");
     if (cd->curve_type == SMOOTH)
     {
       cd->outline = OUTLINE_UPPER;
       bender_calculate_curve (cd, xmax, ymax, FALSE);
       cd->outline = OUTLINE_LOWER;
       bender_calculate_curve (cd, xmax, ymax, FALSE);
     }
     else
     {
       p_stretch_curves(cd, xmax, ymax);
     }
   }
   else
   {
     /* compose curves by iterating between FROM/TO values */
     if(gb_debug)  printf("p_bender_calculate_iter_curve ITERmode 1\n");
   
     /* init FROM curves */
     cd_from = g_new (BenderDialog, 1);
     p_cd_from_bval(cd_from, cd->bval_from);
     cd_from->curve_ptr[OUTLINE_UPPER] = g_new (gint32, 1+xmax);
     cd_from->curve_ptr[OUTLINE_LOWER] = g_new (gint32, 1+xmax);
     
     /* init TO curves */
     cd_to = g_new (BenderDialog, 1);
     p_cd_from_bval(cd_to, cd->bval_to);
     cd_to->curve_ptr[OUTLINE_UPPER] = g_new (gint32, 1+xmax);
     cd_to->curve_ptr[OUTLINE_LOWER] = g_new (gint32, 1+xmax);

     if (cd_from->curve_type == SMOOTH)
     {
       /* calculate FROM curves */
       cd_from->outline = OUTLINE_UPPER;
       bender_calculate_curve (cd_from, xmax, ymax, FALSE);
       cd_from->outline = OUTLINE_LOWER;
       bender_calculate_curve (cd_from, xmax, ymax, FALSE);
     }
     else
     {
       p_stretch_curves(cd_from, xmax, ymax);
     }

     if (cd_to->curve_type == SMOOTH)
     {
       /* calculate TO curves */
       cd_to->outline = OUTLINE_UPPER;
       bender_calculate_curve (cd_to, xmax, ymax, FALSE);
       cd_to->outline = OUTLINE_LOWER;
       bender_calculate_curve (cd_to, xmax, ymax, FALSE);
     }
     else
     {
       p_stretch_curves(cd_to, xmax, ymax);
     }
   
     
     /* MIX Y-koords of the curves according to current iteration step */
     for(l_x = 0; l_x <= xmax; l_x++)
     {
        p_delta_gint32(&cd->curve_ptr[OUTLINE_UPPER][l_x],
                        cd_from->curve_ptr[OUTLINE_UPPER][l_x],
                        cd_to->curve_ptr[OUTLINE_UPPER][l_x],
                        cd->bval_curr->total_steps,
                        cd->bval_curr->current_step);
                        
        p_delta_gint32(&cd->curve_ptr[OUTLINE_LOWER][l_x],
                        cd_from->curve_ptr[OUTLINE_LOWER][l_x],
                        cd_to->curve_ptr[OUTLINE_LOWER][l_x],
                        cd->bval_curr->total_steps,
                        cd->bval_curr->current_step);
     }
     

     g_free(cd_from->curve_ptr[OUTLINE_UPPER]);
     g_free(cd_from->curve_ptr[OUTLINE_LOWER]);
     
     g_free(cd_from);
     g_free(cd_to);
     
   }

   cd->outline = l_outline;
}	/* end p_bender_calculate_iter_curve */

/* ============================================================================
 * p_vertical_bend
 * ============================================================================
 */

int
p_vertical_bend (BenderDialog *cd, 
		 t_GDRW       *src_gdrw, 
		 t_GDRW       *dst_gdrw)
{
   gint32             l_row, l_col;
   gint32             l_first_row, l_first_col, l_last_row, l_last_col;
   gint32             l_x, l_y;
   gint32             l_x2, l_y2;
   gint32             l_curvy, l_nb_curvy, l_nb2_curvy;
   gint32             l_desty, l_othery;
   gint32             l_miny, l_maxy;
   gint32             l_sign, l_dy, l_diff;
   gint32             l_topshift;
   float l_progress_step;
   float l_progress_max;
   float l_progress;

   t_Last            *last_arr;
   t_Last            *first_arr;
   guchar             color[4];
   guchar             mixcolor[4];
   guchar             l_alpha_lo;
   gint               l_alias_dir;
   guchar             l_mixmask;


   l_topshift = p_upper_curve_extend(cd, src_gdrw->drawable->width, src_gdrw->drawable->height);
   l_diff = l_curvy = l_nb_curvy = l_nb2_curvy= l_miny = l_maxy = 0;
   l_alpha_lo = 20;

   /* allocate array of last values (one element foreach x koordinate) */
   last_arr  = g_new (t_Last, src_gdrw->x2);
   first_arr = g_new (t_Last, src_gdrw->x2);

   /* ------------------------------------------------
    * foreach pixel in the SAMPLE_drawable:
    * ------------------------------------------------
    * the inner loops (l_x/l_y) are designed to process
    * all pixels of one tile in the sample drawable, the outer loops (row/col) do step
    * to the next tiles. (this was done to reduce tile swapping)
    */

   l_first_row = src_gdrw->y1 / src_gdrw->tile_height;
   l_last_row  = (src_gdrw->y2 / src_gdrw->tile_height);
   l_first_col = src_gdrw->x1 / src_gdrw->tile_width;
   l_last_col  = (src_gdrw->x2 / src_gdrw->tile_width);
 
   /* init progress */
   l_progress_max = (1 + l_last_row - l_first_row) * (1 + l_last_col - l_first_col);
   l_progress_step = 1.0 / l_progress_max;
   l_progress = 0.0;
   if(cd->show_progress) gimp_progress_init ( _("Curve Bend..."));

   for(l_row = l_first_row; l_row <= l_last_row; l_row++)
   {
     for(l_col = l_first_col; l_col <= l_last_col; l_col++)
     {
       if(l_col == l_first_col)    l_x = src_gdrw->x1;
       else                        l_x = l_col * src_gdrw->tile_width;
       if(l_col == l_last_col)     l_x2 = src_gdrw->x2;
       else                        l_x2 = (l_col +1) * src_gdrw->tile_width;

       if(cd->show_progress) gimp_progress_update (l_progress += l_progress_step);    
       
       for( ; l_x < l_x2; l_x++)
       {
         if(l_row == l_first_row)    l_y = src_gdrw->y1;
         else                        l_y = l_row * src_gdrw->tile_height;
         if(l_row == l_last_row)     l_y2 = src_gdrw->y2;
         else                        l_y2 = (l_row +1) * src_gdrw->tile_height ;

         /* printf("X: %4d Y:%4d Y2:%4d\n", (int)l_x, (int)l_y, (int)l_y2); */
       
         for( ; l_y < l_y2; l_y++)
         {
            /* ---------- copy SRC_PIXEL to curve position ------ */
            
	    p_get_pixel(src_gdrw, l_x, l_y, &color[0]);            

            l_curvy = p_curve_get_dy(cd, l_x, 
                                    (gint32)src_gdrw->drawable->width, 
                                    (gint32)src_gdrw->drawable->height, (gdouble)l_y);
            l_desty = l_y + l_topshift + l_curvy;
            
            /* ----------- SMOOTING ------------------ */
            if((cd->smoothing == TRUE) && (l_x > 0))
            {
               l_nb_curvy = p_curve_get_dy(cd, l_x -1, 
                                    (gint32)src_gdrw->drawable->width, 
                                    (gint32)src_gdrw->drawable->height, (gdouble)l_y);
               if((l_nb_curvy == l_curvy) && (l_x > 1))
               {
                    l_nb2_curvy = p_curve_get_dy(cd, l_x -2, 
                                    (gint32)src_gdrw->drawable->width, 
                                    (gint32)src_gdrw->drawable->height, (gdouble)l_y);
               }
               else
               {
                    l_nb2_curvy = l_nb_curvy;
               }
               p_put_mix_pixel(dst_gdrw, l_x, l_desty, &color[0], l_nb_curvy, l_nb2_curvy, l_curvy );
            }
            else
            {
               p_put_pixel(dst_gdrw, l_x, l_desty, &color[0]);
            }

            /* ----------- render ANTIALIAS ------------------ */

            if(cd->antialias)
            {
               l_othery = l_desty;
               
               if(l_y == src_gdrw->y1)             /* Upper outline */
               {
                  first_arr[l_x].y = l_curvy;
                  memcpy(&first_arr[l_x].color[0], &color[0], dst_gdrw->drawable->bpp);
                    
                  if(l_x > 0)
                  {
                    memcpy(&mixcolor[0], &first_arr[l_x-1].color[0], dst_gdrw->drawable->bpp);
                     
                    l_diff = abs(first_arr[l_x - 1].y - l_curvy) +1;
                    l_miny = MIN(first_arr[l_x - 1].y, l_curvy) -1;
                    l_maxy = MAX(first_arr[l_x - 1].y, l_curvy) +1;

		    l_othery = (src_gdrw->y2 -1) 
		             + l_topshift 
		             + p_curve_get_dy(cd, l_x, 
                                              (gint32)src_gdrw->drawable->width, 
                                              (gint32)src_gdrw->drawable->height,
				              (gdouble)(src_gdrw->y2 -1));
                   }
               }
               if(l_y == src_gdrw->y2 -1)      /* Lower outline */
               {
                  if(l_x > 0)
                  {
                    memcpy(&mixcolor[0], &last_arr[l_x-1].color[0], dst_gdrw->drawable->bpp);
                     
                    l_diff = abs(last_arr[l_x - 1].y - l_curvy) +1;
                    l_maxy = MAX(last_arr[l_x - 1].y, l_curvy) +1;
                    l_miny = MIN(last_arr[l_x - 1].y, l_curvy) -1;
                   }

		    l_othery = (src_gdrw->y1) 
		             + l_topshift 
		             + p_curve_get_dy(cd, l_x, 
                                              (gint32)src_gdrw->drawable->width, 
                                              (gint32)src_gdrw->drawable->height,
				              (gdouble)(src_gdrw->y1));
               }

	       if(l_desty < l_othery)        { l_alias_dir =  1; }  /* fade to transp. with descending dy */
	       else if(l_desty > l_othery)   { l_alias_dir = -1; }  /* fade to transp. with ascending dy */
	       else                          { l_alias_dir =  0; }  /* no antialias at curve crossing point(s) */
	       
	       if(l_alias_dir != 0)
	       {
	           l_alpha_lo = 20;
                   if (gimp_drawable_has_alpha(src_gdrw->drawable->drawable_id))
                   {
                     l_alpha_lo = MIN(20, mixcolor[src_gdrw->index_alpha]);
                   }
                     
	       
                   for(l_dy = 0; l_dy < l_diff; l_dy++)
                   {
                        /* iterate for fading alpha channel */
                        l_mixmask =  255 * ((gdouble)(l_dy+1) / (gdouble)(l_diff+1));
                        mixcolor[dst_gdrw->index_alpha] = MIX_CHANNEL(color[dst_gdrw->index_alpha], l_alpha_lo, l_mixmask);
			if(l_alias_dir > 0)
			{
                          p_put_pixel(dst_gdrw, l_x -1, l_y + l_topshift  + l_miny + l_dy, &mixcolor[0]);
			}
			else
			{
                          p_put_pixel(dst_gdrw, l_x -1, l_y + l_topshift  + (l_maxy - l_dy), &mixcolor[0]);
			}

                   }
	       }
            }

            /* ------------------ FILL HOLES ------------------ */

            if(l_y == src_gdrw->y1)
            {
               l_diff = 0;
               l_sign = 1;
            }
            else
            {
               l_diff = last_arr[l_x].y - l_curvy;
               if (l_diff < 0)
               {
                  l_diff = 0 - l_diff;
                  l_sign = -1;
               }
               else
               {
                  l_sign = 1;
               }
               
               memcpy(&mixcolor[0], &color[0], dst_gdrw->drawable->bpp);
            }
            
            for(l_dy = 1; l_dy <= l_diff; l_dy++)
            {
               /* y differs more than 1 pixel from last y in the destination
                * drawable. So we have to fill the empty space between
                * using a mixed color
                */

               if(cd->smoothing == TRUE)
               {
                 /* smooting is on, so we are using a mixed color */
                 gulong alpha1 = last_arr[l_x].color[3];
                 gulong alpha2 = color[3];
                 gulong alpha;
                 l_mixmask =  255 * ((gdouble)(l_dy) / (gdouble)(l_diff+1));
                 alpha = alpha1 * l_mixmask + alpha2 * (255 - l_mixmask);
                 mixcolor[3] = alpha/255;
                 if (mixcolor[3])
                   {
                     mixcolor[0] = (alpha1 * l_mixmask * last_arr[l_x].color[0]
                                    + alpha2 * (255 - l_mixmask) * color[0])/alpha;
                     mixcolor[1] = (alpha1 * l_mixmask * last_arr[l_x].color[1]
                                    + alpha2 * (255 - l_mixmask) * color[1])/alpha;
                     mixcolor[2] = (alpha1 * l_mixmask * last_arr[l_x].color[2]
                                    + alpha2 * (255 - l_mixmask) * color[2])/alpha;
                     /*mixcolor[2] =  MIX_CHANNEL(last_arr[l_x].color[2], color[2], l_mixmask);*/
                   }
               }
               else
               {
                  /* smooting is off, so we are using this color or the last color */
                  if(l_dy < l_diff / 2)
                  {
                    memcpy(&mixcolor[0], &color[0], dst_gdrw->drawable->bpp);
                  }
                  else
                  {
                    memcpy(&mixcolor[0], &last_arr[l_x].color[0], dst_gdrw->drawable->bpp);
                  }
               }
               
               if(cd->smoothing == TRUE)
               {
                  p_put_mix_pixel(dst_gdrw, l_x, l_desty + (l_dy * l_sign), &mixcolor[0],
                                  l_nb_curvy, l_nb2_curvy, l_curvy );
               }
               else
               {
                  p_put_pixel(dst_gdrw, l_x, l_desty + (l_dy * l_sign), &mixcolor[0]);               
               }
            }
            
            /* store y and color */ 
            last_arr[l_x].y = l_curvy;
            memcpy(&last_arr[l_x].color[0], &color[0], dst_gdrw->drawable->bpp);
            

         }
       }
     }
   }

   if (gb_debug) 
     printf("ROWS: %d - %d  COLS: %d - %d\n", 
	    (int)l_first_row, (int)l_last_row, (int)l_first_col, (int)l_last_col);

   return 0;

}

/* ============================================================================
 * p_main_bend
 * ============================================================================
 */

gint32
p_main_bend (BenderDialog *cd, 
	     GimpDrawable    *original_drawable, 
	     gint          work_on_copy)
{
   t_GDRW  l_src_gdrw;
   t_GDRW  l_dst_gdrw;
   GimpDrawable *dst_drawable;
   GimpDrawable *src_drawable;
   gint32    l_dst_height;
   gint32    l_image_id;
   gint32    l_tmp_layer_id;
   gint32    l_interpolation;
   gint      l_offset_x, l_offset_y;
   gint      l_center_x, l_center_y;
   gint32    xmax, ymax;
  
   l_interpolation = cd->smoothing;
   l_image_id = gimp_layer_get_image_id(original_drawable->drawable_id);
   gimp_drawable_offsets(original_drawable->drawable_id, &l_offset_x, &l_offset_y);

   l_center_x = l_offset_x + (gimp_drawable_width  (original_drawable->drawable_id) / 2 );
   l_center_y = l_offset_y + (gimp_drawable_height (original_drawable->drawable_id) / 2 );
   
   /* always copy original_drawable to a tmp src_layer */  
   l_tmp_layer_id = gimp_layer_copy(original_drawable->drawable_id);
   /* set layer invisible and dummyname and 
    * add at top of the image while working
    * (for the case of undo the gimp must know,
    *  that the layer was part of the image)
    */
   gimp_image_add_layer (l_image_id, l_tmp_layer_id, 0);
   gimp_layer_set_visible(l_tmp_layer_id, FALSE);
   gimp_layer_set_name(l_tmp_layer_id, "curve_bend_dummylayer");
    
   if(gb_debug) printf("p_main_bend  l_tmp_layer_id %d\n", (int)l_tmp_layer_id);   
   
   if(cd->rotation != 0.0)
   {
      if(gb_debug) printf("p_main_bend rotate: %f\n", (float)cd->rotation);   
      p_gimp_rotate(l_image_id, l_tmp_layer_id, l_interpolation, cd->rotation);
   }
   src_drawable = gimp_drawable_get (l_tmp_layer_id);

   xmax = ymax = src_drawable->width -1;
   cd->curve_ptr[OUTLINE_UPPER] = g_new (gint32, 1+xmax);
   cd->curve_ptr[OUTLINE_LOWER] = g_new (gint32, 1+xmax);

   p_bender_calculate_iter_curve(cd, xmax, ymax);
   bender_init_min_max(cd, xmax);
   
   l_dst_height = src_drawable->height 
                + p_upper_curve_extend(cd, src_drawable->width, src_drawable->height)
                + p_lower_curve_extend(cd, src_drawable->width, src_drawable->height);

   if(gb_debug) printf("p_main_bend: l_dst_height:%d\n", (int)l_dst_height);   

   if(work_on_copy)
   {
     dst_drawable = p_add_layer(src_drawable->width, l_dst_height, src_drawable);
     if(gb_debug) printf("p_main_bend: DONE add layer\n");   
   }
   else
   {
     /* work on the original */
     gimp_layer_resize(original_drawable->drawable_id, 
                       src_drawable->width,
		       l_dst_height,
		       l_offset_x, l_offset_y);
     if(gb_debug) printf("p_main_bend: DONE layer resize\n");   
     if(!gimp_drawable_has_alpha(original_drawable->drawable_id))
     {
       /* always add alpha channel */
       gimp_layer_add_alpha(original_drawable->drawable_id);
     }
     dst_drawable = gimp_drawable_get (original_drawable->drawable_id);
   }
   p_clear_drawable(dst_drawable);

   p_init_gdrw(&l_src_gdrw, src_drawable, FALSE, FALSE);
   p_init_gdrw(&l_dst_gdrw, dst_drawable,  TRUE,  FALSE);

   p_vertical_bend(cd, &l_src_gdrw, &l_dst_gdrw);

   if(gb_debug) printf("p_main_bend: DONE vertical bend\n");   

   p_end_gdrw(&l_src_gdrw);
   p_end_gdrw(&l_dst_gdrw);

   if(cd->rotation != 0.0)
   {
      p_gimp_rotate(l_image_id, dst_drawable->drawable_id, l_interpolation, (gdouble)(360.0 - cd->rotation));
      
      /* TODO: here we should crop dst_drawable to cut off full transparent borderpixels */
      
   }

   /* set offsets of the resulting new layer 
    *(center == center of original_drawable)
    */
   l_offset_x = l_center_x - (gimp_drawable_width  (dst_drawable->drawable_id) / 2 );
   l_offset_y = l_center_y - (gimp_drawable_height  (dst_drawable->drawable_id) / 2 );
   gimp_layer_set_offsets (dst_drawable->drawable_id, l_offset_x, l_offset_y);

   /* delete the temp layer */
   gimp_image_remove_layer(l_image_id, l_tmp_layer_id);

   g_free(cd->curve_ptr[OUTLINE_UPPER]);
   g_free(cd->curve_ptr[OUTLINE_LOWER]);

   if(gb_debug) printf("p_main_bend: DONE bend main\n");   

   return dst_drawable->drawable_id;
}	/* end p_main_bend */