gimp/app/tools/gimpcagetool.c

/* GIMP - The GNU Image Manipulation Program
 *
 * gimpcagetool.c
 * Copyright (C) 2010 Michael Muré <batolettre@gmail.com>
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */


#include "config.h"

#include <string.h>

#include <gegl.h>
#include <gtk/gtk.h>
#include <gdk/gdkkeysyms.h>

#include "libgimpmath/gimpmath.h"
#include "libgimpwidgets/gimpwidgets.h"

#include "tools-types.h"
#include "tools/tools-enums.h"
#include "gimptoolcontrol.h"

#include "core/core-types.h"

#include "core/gimp.h"
#include "core/gimpprogress.h"
#include "core/gimpimage.h"
#include "core/gimplayer.h"
#include "core/gimp-transform-utils.h"
#include "core/gimpdrawable.h"
#include "core/gimpdrawable-operation.h"
#include "core/gimpdrawable-shadow.h"
#include "core/gimpimagemap.h"
#include "core/gimpprojection.h"

#include "display/gimpdisplay.h"
#include "display/gimpdisplayshell.h"
#include "display/gimpdisplayshell-transform.h"

#include "base/tile-manager.h"

#include "widgets/gimphelp-ids.h"

#include "gimpcagetool.h"
#include "gimpcageoptions.h"

#include "gimp-intl.h"

#include <stdio.h>

/*static gboolean     gimp_cage_tool_initialize     (GimpTool    *tool,
                                                   GimpDisplay *display,
                                                   GError     **error);*/
static void         gimp_cage_tool_finalize           (GObject               *object);
static void         gimp_cage_tool_start              (GimpCageTool          *ct,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_halt               (GimpCageTool          *ct);
static void         gimp_cage_tool_button_press       (GimpTool              *tool,
                                                       const GimpCoords      *coords,
                                                       guint32                time,
                                                       GdkModifierType        state,
                                                       GimpButtonPressType    press_type,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_button_release     (GimpTool              *tool,
                                                       const GimpCoords      *coords,
                                                       guint32                time,
                                                       GdkModifierType        state,
                                                       GimpButtonReleaseType  release_type,
                                                       GimpDisplay           *display);
static gboolean     gimp_cage_tool_key_press          (GimpTool              *tool,
                                                       GdkEventKey           *kevent,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_motion             (GimpTool              *tool,
                                                       const GimpCoords      *coords,
                                                       guint32                time,
                                                       GdkModifierType        state,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_control            (GimpTool              *tool,
                                                       GimpToolAction         action,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_cursor_update      (GimpTool              *tool,
                                                       const GimpCoords      *coords,
                                                       GdkModifierType        state,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_oper_update        (GimpTool              *tool,
                                                       const GimpCoords      *coords,
                                                       GdkModifierType        state,
                                                       gboolean               proximity,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_draw               (GimpDrawTool          *draw_tool);
static void         gimp_cage_tool_switch_to_deform   (GimpCageTool          *ct);
static void         gimp_cage_tool_remove_last_handle (GimpCageTool          *ct);
static void         gimp_cage_tool_compute_coef       (GimpCageTool          *ct,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_process            (GimpCageTool          *ct,
                                                       GimpDisplay           *display);
static void         gimp_cage_tool_prepare_preview    (GimpCageTool          *ct,
                                                       GimpDisplay           *display);
static gboolean     gimp_cage_tool_update_preview     (GimpTool              *tool);

G_DEFINE_TYPE (GimpCageTool, gimp_cage_tool, GIMP_TYPE_DRAW_TOOL)

#define parent_class gimp_cage_tool_parent_class

#define HANDLE_SIZE             14

void
gimp_cage_tool_register (GimpToolRegisterCallback  callback,
                           gpointer                  data)
{
  (* callback) (GIMP_TYPE_CAGE_TOOL, //Tool type
                GIMP_TYPE_CAGE_OPTIONS, //Tool options type
                gimp_cage_options_gui, //Tool opions gui
                0, //context_props
                "gimp-cage-tool",
                _("Cage Transform"),
                _("Cage Transform: Deform a selection with a cage"),
                N_("_Cage Transform"), "<shift>R",
                NULL, GIMP_HELP_TOOL_CAGE,
                GIMP_STOCK_TOOL_CAGE,
                data);
}

static void
gimp_cage_tool_class_init (GimpCageToolClass *klass)
{
  GObjectClass           *object_class         = G_OBJECT_CLASS (klass);
  GimpToolClass          *tool_class           = GIMP_TOOL_CLASS (klass);
  GimpDrawToolClass      *draw_tool_class      = GIMP_DRAW_TOOL_CLASS (klass);

  object_class->finalize          = gimp_cage_tool_finalize;

  /*tool_class->initialize          = gimp_cage_tool_initialize;*/
  tool_class->button_press        = gimp_cage_tool_button_press;
  tool_class->button_release      = gimp_cage_tool_button_release;
  tool_class->key_press           = gimp_cage_tool_key_press;
  tool_class->motion              = gimp_cage_tool_motion;
  tool_class->control             = gimp_cage_tool_control;
  tool_class->cursor_update       = gimp_cage_tool_cursor_update;
  tool_class->oper_update         = gimp_cage_tool_oper_update;

  draw_tool_class->draw           = gimp_cage_tool_draw;
}

static void
gimp_cage_tool_init (GimpCageTool *self)
{
  self->config = g_object_new (GIMP_TYPE_CAGE_CONFIG, NULL);
  self->cursor_position.x = 0;
  self->cursor_position.y = 0;
  self->handle_moved = -1;
  self->cage_complete = FALSE;

  self->coef = NULL;
  self->image_map = NULL;
  self->node_preview = NULL;

  self->idle_id = 0;
}

/*static gboolean
gimp_cage_tool_initialize (GimpTool    *tool,
                           GimpDisplay *display,
                           GError     **error)
{
  GimpCageTool *cage_tool = GIMP_CAGE_TOOL (tool);

  return GIMP_TOOL_CLASS (parent_class)->initialize(tool, display, error);
}*/

static void
gimp_cage_tool_finalize (GObject *object)
{
  GimpCageTool        *ct  = GIMP_CAGE_TOOL (object);

  gimp_cage_tool_halt (ct);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}



static void
gimp_cage_tool_start (GimpCageTool       *ct,
                      GimpDisplay        *display)
{
  GimpTool                  *tool      = GIMP_TOOL (ct);
  GimpDrawTool              *draw_tool = GIMP_DRAW_TOOL (tool);

  gimp_tool_control_activate (tool->control);

  tool->display = display;

  if (ct->config)
  {
    g_object_unref (ct->config);
  }

  if (ct->image_map)
  {
    gimp_image_map_abort (ct->image_map);
    g_object_unref (ct->image_map);
  }

  ct->config = g_object_new (GIMP_TYPE_CAGE_CONFIG, NULL);
  ct->cursor_position.x = -1000;
  ct->cursor_position.y = -1000;
  ct->handle_moved = -1;
  ct->cage_complete = FALSE;

  gimp_draw_tool_start (draw_tool, display);
}

static void
gimp_cage_tool_halt (GimpCageTool *ct)
{
  GimpTool                  *tool      = GIMP_TOOL (ct);
  GimpDrawTool              *draw_tool = GIMP_DRAW_TOOL (ct);

  if (gimp_draw_tool_is_active (draw_tool))
    gimp_draw_tool_stop (draw_tool);

  if (gimp_tool_control_is_active (tool->control))
    gimp_tool_control_halt (tool->control);

  if (ct->config)
  {
    g_object_unref (ct->config);
    ct->config = NULL;
  }

  if (ct->coef)
  {
    gegl_buffer_destroy (ct->coef);
    ct->coef = NULL;
  }

  if (ct->image_map)
  {
    gimp_tool_control_set_preserve (tool->control, TRUE);

    gimp_image_map_abort (ct->image_map);
    g_object_unref (ct->image_map);
    ct->image_map = NULL;

    gimp_tool_control_set_preserve (tool->control, FALSE);

    gimp_image_flush (gimp_display_get_image (tool->display));
  }

  if (ct->node_preview)
  {
    g_object_unref (ct->node_preview);
    ct->node_preview = NULL;
  }

  tool->display  = NULL;
}

static void
gimp_cage_tool_button_press (GimpTool              *tool,
                             const GimpCoords      *coords,
                             guint32                time,
                             GdkModifierType        state,
                             GimpButtonPressType    press_type,
                             GimpDisplay           *display)
{
  GimpCageTool      *ct       = GIMP_CAGE_TOOL (tool);
  GimpCageOptions   *options  = GIMP_CAGE_TOOL_GET_OPTIONS (ct);
  GimpCageConfig    *config   = ct->config;

  g_return_if_fail (GIMP_IS_CAGE_TOOL (ct));

  if (display != tool->display)
  {
    gimp_cage_tool_start  (ct,
                           display);
    config   = ct->config;
  }

  gimp_draw_tool_pause (GIMP_DRAW_TOOL (ct));


  if (ct->handle_moved < 0)
  {
    ct->handle_moved = gimp_cage_config_is_on_handle  (config,
                                                       options->cage_mode,
                                                       coords->x,
                                                       coords->y,
                                                       HANDLE_SIZE);
    if (ct->handle_moved > 0 && ct->idle_id > 0)
      {
        g_source_remove(ct->idle_id);
        ct->idle_id = 0; /*Stop preview update for now*/
      }
  }

  if (ct->handle_moved < 0 && !ct->cage_complete)
  {
    gimp_cage_config_add_cage_point (config,
                                    coords->x,
                                    coords->y);
  }

  gimp_draw_tool_resume (GIMP_DRAW_TOOL (ct));

  // user is clicking on the first handle, we close the cage and switch to deform mode
  if (ct->handle_moved == 0 && config->cage_vertice_number > 2 && !ct->coef)
  {
    ct->cage_complete = TRUE;
    gimp_cage_tool_switch_to_deform (ct);

    gimp_cage_config_reverse_cage_if_needed (config);
    gimp_cage_tool_compute_coef (ct, display);
    gimp_cage_tool_prepare_preview (ct, display);

    printf("Swiched to deform\n");
  }

}

void
gimp_cage_tool_button_release (GimpTool              *tool,
                               const GimpCoords      *coords,
                               guint32                time,
                               GdkModifierType        state,
                               GimpButtonReleaseType  release_type,
                               GimpDisplay           *display)
{
  GimpCageTool *ct = GIMP_CAGE_TOOL (tool);


  if (ct->coef && ct->handle_moved > -1)
  {

    GimpDisplayShell *shell = gimp_display_get_shell (tool->display);
    GimpImage *image = gimp_display_get_image (tool->display);
    GimpItem         *item  = GIMP_ITEM (tool->drawable);

    gint              x, y;
    gint              w, h;
    gint              off_x, off_y;
    GeglRectangle     visible;

    gimp_display_shell_untransform_viewport (shell, &x, &y, &w, &h);

    gimp_item_get_offset (item, &off_x, &off_y);

    gimp_rectangle_intersect (x, y, w, h,
                              off_x,
                              off_y,
                              gimp_item_get_width  (item),
                              gimp_item_get_height (item),
                              &visible.x,
                              &visible.y,
                              &visible.width,
                              &visible.height);

    visible.x -= off_x;
    visible.y -= off_y;

    gimp_draw_tool_pause (GIMP_DRAW_TOOL (ct));

    printf("Start to update preview\n");

    gimp_image_map_apply (ct->image_map, &visible);

    ct->idle_id = g_idle_add ((GSourceFunc) gimp_cage_tool_update_preview, tool);

    gimp_projection_flush_now (gimp_image_get_projection (image));
    gimp_display_flush_now (tool->display);


    gimp_draw_tool_resume (GIMP_DRAW_TOOL (ct));
  }
  ct->handle_moved = -1;

}

static gboolean
gimp_cage_tool_update_preview (GimpTool *tool)
{
  GimpCageTool *ct = GIMP_CAGE_TOOL (tool);
  GimpImage *image = gimp_display_get_image (tool->display);


    gimp_projection_flush_now (gimp_image_get_projection (image));
    gimp_display_flush_now (tool->display);

    if (!gimp_image_map_is_busy(ct->image_map))
      {
        ct->idle_id = 0;
        printf ("Preview update complete\n");

        return FALSE;
      }

  return TRUE;


}
static gboolean
gimp_cage_tool_key_press (GimpTool    *tool,
                          GdkEventKey *kevent,
                          GimpDisplay *display)
{
  GimpCageTool *ct    = GIMP_CAGE_TOOL (tool);

  switch (kevent->keyval)
    {
    case GDK_BackSpace:
      gimp_cage_tool_remove_last_handle (ct);
      return TRUE;

    case GDK_Return:
    case GDK_KP_Enter:
    case GDK_ISO_Enter:
      if (ct->cage_complete)
      {
        gimp_image_map_abort (ct->image_map);
        g_object_unref (ct->image_map);
        ct->image_map = NULL;
        if (ct->idle_id)
          {
            g_source_remove(ct->idle_id);
            ct->idle_id = 0; /*Stop preview update for now*/
          }
        gimp_cage_tool_process (ct, display); /*RUN IT BABY*/
      }
      return TRUE;

    case GDK_Escape:
      gimp_cage_tool_halt (ct);
      return TRUE;

    default:
      break;
    }

  return FALSE;
}

static void
gimp_cage_tool_motion (GimpTool         *tool,
                        const GimpCoords *coords,
                        guint32           time,
                        GdkModifierType   state,
                        GimpDisplay      *display)
{
  GimpCageTool        *ct         = GIMP_CAGE_TOOL (tool);
  GimpDrawTool        *draw_tool  = GIMP_DRAW_TOOL (tool);
  GimpCageOptions     *options    = GIMP_CAGE_TOOL_GET_OPTIONS (ct);
  GimpCageConfig      *config     = ct->config;


  gimp_draw_tool_pause (draw_tool);


  if (ct->handle_moved >= 0)
  {
    gimp_cage_config_move_cage_point  (config,
                                      options->cage_mode,
                                      ct->handle_moved,
                                      coords->x,
                                      coords->y);
  }

  gimp_draw_tool_resume (draw_tool);
}

static void
gimp_cage_tool_control (GimpTool       *tool,
                         GimpToolAction  action,
                         GimpDisplay    *display)
{
  switch (action)
    {
    case GIMP_TOOL_ACTION_PAUSE:
    case GIMP_TOOL_ACTION_RESUME:
      break;

    case GIMP_TOOL_ACTION_HALT:
      gimp_cage_tool_halt (GIMP_CAGE_TOOL (tool));
      break;
    }

  GIMP_TOOL_CLASS (parent_class)->control (tool, action, display);
}

static void
gimp_cage_tool_cursor_update  (GimpTool         *tool,
                               const GimpCoords *coords,
                               GdkModifierType   state,
                               GimpDisplay      *display)
{
  GimpCageTool    *ct       = GIMP_CAGE_TOOL (tool);
  GimpCageOptions *options  = GIMP_CAGE_TOOL_GET_OPTIONS (ct);

  if (tool->display == NULL)
  {
    GIMP_TOOL_CLASS (parent_class)->cursor_update (tool,
                                                   coords,
                                                   state,
                                                   display);
  }
  else
  {
    GimpCursorModifier modifier;

    if (options->cage_mode == GIMP_CAGE_MODE_CAGE_CHANGE)
    {
      modifier = GIMP_CURSOR_MODIFIER_ANCHOR;
    }
    else
    {
      modifier = GIMP_CURSOR_MODIFIER_MOVE;
    }

    gimp_tool_set_cursor (tool, display,
                          gimp_tool_control_get_cursor (tool->control),
                          gimp_tool_control_get_tool_cursor (tool->control),
                          modifier);
  }
}

static void
gimp_cage_tool_oper_update  (GimpTool         *tool,
                             const GimpCoords *coords,
                             GdkModifierType   state,
                             gboolean          proximity,
                             GimpDisplay      *display)
{
  GimpCageTool    *ct          = GIMP_CAGE_TOOL (tool);
  GimpDrawTool    *draw_tool   = GIMP_DRAW_TOOL (tool);
  GimpCageOptions *options     = GIMP_CAGE_TOOL_GET_OPTIONS (ct);
  GimpCageConfig  *config      = ct->config;
  gint             active_handle = -1;

  if (config)
    active_handle = gimp_cage_config_is_on_handle (config,
                                                   options->cage_mode,
                                                   coords->x,
                                                   coords->y,
                                                   HANDLE_SIZE);
  if (!ct->cage_complete || (active_handle > -1))
    {
      gimp_draw_tool_pause (draw_tool);

      ct->cursor_position.x = coords->x;
      ct->cursor_position.y = coords->y;

      gimp_draw_tool_resume (draw_tool);
    }
}

/**
 * gimp_cage_tool_draw:
 * @draw_tool:
 *
 * Draw the tool on the canvas.
 */
static void
gimp_cage_tool_draw (GimpDrawTool *draw_tool)
{
  GimpCageTool        *ct       = GIMP_CAGE_TOOL (draw_tool);
  GimpCageOptions     *options  = GIMP_CAGE_TOOL_GET_OPTIONS (ct);
  GimpCageConfig      *config   = ct->config;

  gint                 i = 0;
  gint                 on_handle = -1;
  GimpVector2         *vertices;


  if (config->cage_vertice_number <= 0)
  {
    return;
  }

  if (options->cage_mode == GIMP_CAGE_MODE_CAGE_CHANGE)
  {
    vertices = config->cage_vertices;
  }
  else
  {
    vertices = config->cage_vertices_d;
  }


  gimp_draw_tool_draw_lines (draw_tool,
                             vertices,
                             config->cage_vertice_number,
                             FALSE, FALSE);

  if (!ct->cage_complete && ct->cursor_position.x != -1000)
  {
    gimp_draw_tool_draw_line (draw_tool,
                              vertices[config->cage_vertice_number - 1].x,
                              vertices[config->cage_vertice_number - 1].y,
                              ct->cursor_position.x,
                              ct->cursor_position.y,
                              FALSE);
  }
  else
  {
    gimp_draw_tool_draw_line (draw_tool,
                              vertices[config->cage_vertice_number - 1].x,
                              vertices[config->cage_vertice_number - 1].y,
                              vertices[0].x,
                              vertices[0].y,
                              FALSE);
  }

  on_handle = gimp_cage_config_is_on_handle (config,
                                             options->cage_mode,
                                             ct->cursor_position.x,
                                             ct->cursor_position.y,
                                             HANDLE_SIZE);

  for(i = 0; i < config->cage_vertice_number; i++)
  {
    GimpVector2 point = vertices[i];

    GimpHandleType handle = GIMP_HANDLE_CIRCLE;

    if (i == on_handle)
    {
      handle = GIMP_HANDLE_FILLED_CIRCLE;
    }

    gimp_draw_tool_draw_handle (draw_tool, handle,
                                point.x,
                                point.y,
                                HANDLE_SIZE, HANDLE_SIZE,
                                GTK_ANCHOR_CENTER, FALSE);
  }
}

static void
gimp_cage_tool_switch_to_deform (GimpCageTool *ct)
{
  GimpCageOptions *options  = GIMP_CAGE_TOOL_GET_OPTIONS (ct);

  g_object_set (options, "cage-mode", GIMP_CAGE_MODE_DEFORM, NULL);
}

static void
gimp_cage_tool_remove_last_handle (GimpCageTool *ct)
{
  GimpCageConfig      *config   = ct->config;

  gimp_draw_tool_pause (GIMP_DRAW_TOOL (ct));
  gimp_cage_config_remove_last_cage_point (config);
  gimp_draw_tool_resume (GIMP_DRAW_TOOL (ct));
}

static void
gimp_cage_tool_compute_coef (GimpCageTool *ct,
                             GimpDisplay  *display)
{
  GimpCageConfig    *config   = ct->config;

  Babl *format;
  GeglNode *gegl, *input, *output;
  GeglProcessor *processor;
  GimpProgress *progress;
  GeglBuffer *buffer;
  gdouble value;

  if (ct->coef)
  {
    gegl_buffer_destroy (ct->coef);
    ct->coef = NULL;
  }

  format = babl_format_n(babl_type("float"), config->cage_vertice_number * 2);

  progress = gimp_progress_start (GIMP_PROGRESS (display),
                                _("Coefficient computation"),
                                FALSE);

  gegl = gegl_node_new ();

  input = gegl_node_new_child (gegl,
                                "operation", "gimp:cage_coef_calc",
                                "config", ct->config,
                                NULL);

  output = gegl_node_new_child (gegl,
                              "operation", "gegl:buffer-sink",
                              "buffer", &buffer,
                              "format", format,
                              NULL);

  gegl_node_connect_to (input, "output",
                          output, "input");

  processor = gegl_node_new_processor (output, NULL);

  while (gegl_processor_work (processor, &value))
  {
      gimp_progress_set_value (progress, value);
  }

  gimp_progress_end (progress);
  gegl_processor_destroy (processor);

  ct->coef = buffer;
  g_object_unref (gegl);
}

static void
gimp_cage_tool_process (GimpCageTool *ct,
                        GimpDisplay  *display)
{
  GimpCageOptions   *options  = GIMP_CAGE_TOOL_GET_OPTIONS (ct);
  TileManager       *new_tiles;
  GeglRectangle      rect;

  GimpImage     *image    = gimp_display_get_image (display);
  GimpDrawable  *drawable = gimp_image_get_active_drawable (image);
  GimpProgress  *progress;
  GeglProcessor *processor;
  gdouble value;

  g_return_if_fail (ct->coef);


  if (GIMP_IS_LAYER (drawable))
  {
    GeglNode *gegl = gegl_node_new ();

#if FALSE
    /* debug coeficient */
    GeglNode *coef, *debug, *output;

    coef = gegl_node_new_child (gegl,
                                "operation", "gegl:buffer-source",
                                "buffer",    ct->coef,
                                NULL);

    new_tiles = gimp_drawable_get_shadow_tiles (drawable);
    output = gegl_node_new_child (gegl,
                                  "operation",    "gimp:tilemanager-sink",
                                  "tile-manager", new_tiles,
                                  "linear",       TRUE,
                                  NULL);

    debug = gegl_node_new_child (gegl,
                                  "operation", "gegl:debugit",
                                  NULL);

    gegl_node_connect_to (coef, "output",
                          debug, "input");

    gegl_node_connect_to (debug, "output",
                          output, "input");
#else
    #if TRUE
      /* reverse transform */
      GeglNode *coef, *cage, *render, *input, *output;

      input  = gegl_node_new_child (gegl,
                                    "operation",    "gimp:tilemanager-source",
                                    "tile-manager", gimp_drawable_get_tiles (drawable),
                                    "linear",       TRUE,
                                    NULL);

      cage = gegl_node_new_child (gegl,
                                  "operation", "gimp:cage_transform",
                                  "config", ct->config,
                                  "fill_plain_color", options->fill_plain_color,
                                  NULL);

      coef = gegl_node_new_child (gegl,
                                  "operation", "gegl:buffer-source",
                                  "buffer",    ct->coef,
                                  NULL);

      render = gegl_node_new_child (gegl,
                                    "operation", "gegl:render_mapping",
                                    NULL);

      new_tiles = gimp_drawable_get_shadow_tiles (drawable);
      output = gegl_node_new_child (gegl,
                                    "operation",    "gimp:tilemanager-sink",
                                    "tile-manager", new_tiles,
                                    "linear",       TRUE,
                                    NULL);

      gegl_node_connect_to (input, "output",
                            cage, "input");

      gegl_node_connect_to (input, "output",
                            render, "input");

      gegl_node_connect_to (coef, "output",
                            cage, "aux");

      gegl_node_connect_to (cage, "output",
                            render, "aux");

      gegl_node_connect_to (render, "output",
                            output, "input");
    #else
      /* forward transform */
      GeglNode *coef, *cage, *input, *output;

      input  = gegl_node_new_child (gegl,
                                    "operation",    "gimp:tilemanager-source",
                                    "tile-manager", gimp_drawable_get_tiles (drawable),
                                    "linear",       TRUE,
                                    NULL);

      cage = gegl_node_new_child (gegl,
                                  "operation", "gimp:cage_preview",
                                  "config", ct->config,
                                  NULL);

      coef = gegl_node_new_child (gegl,
                                  "operation", "gegl:buffer-source",
                                  "buffer",    ct->coef,
                                  NULL);

      new_tiles = gimp_drawable_get_shadow_tiles (drawable);
      output = gegl_node_new_child (gegl,
                                    "operation",    "gimp:tilemanager-sink",
                                    "tile-manager", new_tiles,
                                    "linear",       TRUE,
                                    NULL);

      gegl_node_connect_to (input, "output",
                            cage, "input");

      gegl_node_connect_to (coef, "output",
                            cage, "aux");

      gegl_node_connect_to (cage, "output",
                            output, "input");
    #endif
#endif


    progress = gimp_progress_start (GIMP_PROGRESS (display),
                                _("Rendering transform"),
                                FALSE);

    processor = gegl_node_new_processor (output, NULL);

    while (gegl_processor_work (processor, &value))
      {
        gimp_progress_set_value (progress, value);
      }

    rect.x      = 0;
    rect.y      = 0;
    rect.width  = tile_manager_width  (new_tiles);
    rect.height = tile_manager_height (new_tiles);

    gimp_drawable_merge_shadow_tiles (drawable, TRUE, _("Cage transform"));
    gimp_drawable_free_shadow_tiles (drawable);

    gimp_drawable_update (drawable, rect.x, rect.y, rect.width, rect.height);

    g_object_unref (gegl);

    gimp_image_flush (image);

    gimp_progress_end (progress);
    gegl_processor_destroy (processor);

    gimp_cage_tool_halt (ct);
  }
}


static void
gimp_cage_tool_prepare_preview (GimpCageTool *ct,
                                GimpDisplay  *display)
{
  GimpImage    *image    = gimp_display_get_image (display);
  GimpDrawable *drawable = gimp_image_get_active_drawable (image);

  GeglNode *coef, *cage;

  if (ct->node_preview)
  {
    g_object_unref (ct->node_preview);
    ct->node_preview = NULL;
  }

  ct->node_preview  = gegl_node_new ();

  coef = gegl_node_new_child (ct->node_preview,
                              "operation", "gegl:buffer-source",
                              "buffer",    ct->coef,
                              NULL);

  cage = gegl_node_new_child (ct->node_preview,
                                "operation", "gimp:cage_preview",
                                "config", ct->config,
                                NULL);

  gegl_node_connect_to (coef, "output",
                        cage, "aux");

  ct->image_map = gimp_image_map_new (drawable,
                                      _("Cage transform"),
                                      cage,
                                      NULL,
                                      NULL);
}