gimp/app/tools/gimpdrawtool.c

/* The GIMP -- an image manipulation program
 * Copyright (C) 1995-2001 Spencer Kimball, Peter Mattis, and others
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"

#include <gtk/gtk.h>

#include "libgimpmath/gimpmath.h"

#include "tools-types.h"

#include "base/boundary.h"

#include "core/gimpimage.h"
#include "core/gimplist.h"

#include "vectors/gimpanchor.h"
#include "vectors/gimpstroke.h"
#include "vectors/gimpvectors.h"

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

#include "gimpdrawtool.h"


static void          gimp_draw_tool_class_init (GimpDrawToolClass *klass);
static void          gimp_draw_tool_init       (GimpDrawTool      *draw_tool);

static void          gimp_draw_tool_finalize   (GObject           *object);

static void          gimp_draw_tool_control    (GimpTool          *tool,
                                                GimpToolAction     action,
                                                GimpDisplay       *gdisp);

static void          gimp_draw_tool_draw       (GimpDrawTool      *draw_tool);
static void          gimp_draw_tool_real_draw  (GimpDrawTool      *draw_tool);

static inline void   gimp_draw_tool_shift_to_north_west
                                               (gdouble            x,
                                                gdouble            y,
                                                gint               handle_width,
                                                gint               handle_height,
                                                GtkAnchorType      anchor,
                                                gdouble           *shifted_x,
                                                gdouble           *shifted_y);
static inline void   gimp_draw_tool_shift_to_center
                                               (gdouble            x,
                                                gdouble            y,
                                                gint               handle_width,
                                                gint               handle_height,
                                                GtkAnchorType      anchor,
                                                gdouble           *shifted_x,
                                                gdouble           *shifted_y);


static GimpToolClass *parent_class = NULL;


GType
gimp_draw_tool_get_type (void)
{
  static GType tool_type = 0;

  if (! tool_type)
    {
      static const GTypeInfo tool_info =
      {
        sizeof (GimpDrawToolClass),
	(GBaseInitFunc) NULL,
	(GBaseFinalizeFunc) NULL,
	(GClassInitFunc) gimp_draw_tool_class_init,
	NULL,           /* class_finalize */
	NULL,           /* class_data     */
	sizeof (GimpDrawTool),
	0,              /* n_preallocs    */
	(GInstanceInitFunc) gimp_draw_tool_init,
      };

      tool_type = g_type_register_static (GIMP_TYPE_TOOL,
					  "GimpDrawTool",
                                          &tool_info, 0);
    }

  return tool_type;
}

static void
gimp_draw_tool_class_init (GimpDrawToolClass *klass)
{
  GObjectClass  *object_class;
  GimpToolClass *tool_class;

  object_class = G_OBJECT_CLASS (klass);
  tool_class   = GIMP_TOOL_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  object_class->finalize = gimp_draw_tool_finalize;

  tool_class->control    = gimp_draw_tool_control;

  klass->draw            = gimp_draw_tool_real_draw;
}

static void
gimp_draw_tool_init (GimpDrawTool *draw_tool)
{
  draw_tool->gdisp        = NULL;

  draw_tool->paused_count = 0;

  draw_tool->vectors      = NULL;
  draw_tool->transform    = NULL;
}

static void
gimp_draw_tool_finalize (GObject *object)
{
  GimpDrawTool *draw_tool = GIMP_DRAW_TOOL (object);

  if (draw_tool->vectors)
    {
      g_list_foreach (draw_tool->vectors, (GFunc) g_object_unref, NULL);
      g_list_free (draw_tool->vectors);
      draw_tool->vectors = NULL;
    }

  if (draw_tool->transform)
    {
      g_free (draw_tool->transform);
      draw_tool->transform = NULL;
    }

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

static void
gimp_draw_tool_control (GimpTool       *tool,
			GimpToolAction  action,
			GimpDisplay    *gdisp)
{
  GimpDrawTool *draw_tool = GIMP_DRAW_TOOL (tool);

  switch (action)
    {
    case PAUSE:
      gimp_draw_tool_pause (draw_tool);
      break;

    case RESUME:
      gimp_draw_tool_resume (draw_tool);
      break;

    case HALT:
      gimp_draw_tool_stop (draw_tool);
      break;

    default:
      break;
    }

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

static void
gimp_draw_tool_draw (GimpDrawTool *draw_tool)
{
  if (draw_tool->paused_count == 0 && draw_tool->gdisp)
    {
      GIMP_DRAW_TOOL_GET_CLASS (draw_tool)->draw (draw_tool);
    }
}

static void
gimp_draw_tool_real_draw (GimpDrawTool *draw_tool)
{
  GList *list;

  if (! draw_tool->vectors)
    return;

  for (list = draw_tool->vectors; list; list = g_list_next (list))
    {
      GimpVectors *vectors = list->data;
      GimpStroke  *stroke  = NULL;

      while ((stroke = gimp_vectors_stroke_get_next (vectors, stroke)))
        {
          GArray   *coords;
          gboolean  closed;

          coords = gimp_stroke_interpolate (stroke, 1.0, &closed);

          if (coords && coords->len)
            {
              if (draw_tool->transform)
                {
                  gint i;

                  for (i = 0; i < coords->len; i++)
                    {
                      GimpCoords *curr = &g_array_index (coords, GimpCoords, i);

                      gimp_matrix3_transform_point (draw_tool->transform,
                                                    curr->x, curr->y,
                                                    &curr->x, &curr->y);
                    }
                }

              gimp_draw_tool_draw_strokes (draw_tool,
                                           &g_array_index (coords,
                                                           GimpCoords, 0),
                                           coords->len, FALSE, FALSE);
            }

          if (coords)
            g_array_free (coords, TRUE);
        }
    }
}

void
gimp_draw_tool_start (GimpDrawTool *draw_tool,
		      GimpDisplay  *gdisp)
{
  GimpDisplayShell *shell;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));
  g_return_if_fail (GIMP_IS_DISPLAY (gdisp));

  shell = GIMP_DISPLAY_SHELL (gdisp->shell);

  gimp_draw_tool_stop (draw_tool);

  draw_tool->gdisp = gdisp;

  gimp_draw_tool_draw (draw_tool);
}

void
gimp_draw_tool_stop (GimpDrawTool *draw_tool)
{
  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  gimp_draw_tool_draw (draw_tool);

  draw_tool->gdisp = NULL;
}

gboolean
gimp_draw_tool_is_active (GimpDrawTool *draw_tool)
{
  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), FALSE);

  return draw_tool->gdisp != NULL;
}

void
gimp_draw_tool_pause (GimpDrawTool *draw_tool)
{
  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  gimp_draw_tool_draw (draw_tool);

  draw_tool->paused_count++;
}

void
gimp_draw_tool_resume (GimpDrawTool *draw_tool)
{
  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  if (draw_tool->paused_count > 0)
    {
      draw_tool->paused_count--;

      gimp_draw_tool_draw (draw_tool);
    }
  else
    {
      g_warning ("%s: called with draw_tool->paused_count == 0", G_STRFUNC);
    }
}

void
gimp_draw_tool_set_vectors (GimpDrawTool *draw_tool,
                            GList        *vectors)
{
  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  gimp_draw_tool_pause (draw_tool);

  if (draw_tool->vectors)
    {
      g_list_foreach (draw_tool->vectors, (GFunc) g_object_unref, NULL);
      g_list_free (draw_tool->vectors);
      draw_tool->vectors = NULL;
    }

  if (vectors)
    {
      draw_tool->vectors = g_list_copy (vectors);
      g_list_foreach (draw_tool->vectors, (GFunc) g_object_ref, NULL);
    }

  gimp_draw_tool_resume (draw_tool);
}

void
gimp_draw_tool_set_transform (GimpDrawTool *draw_tool,
                              GimpMatrix3  *transform)
{
  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  gimp_draw_tool_pause (draw_tool);

  if (draw_tool->transform)
    {
      g_free (draw_tool->transform);
      draw_tool->transform = NULL;
    }

  if (transform)
    draw_tool->transform = g_memdup (transform, sizeof (GimpMatrix3));

  gimp_draw_tool_resume (draw_tool);
}

gdouble
gimp_draw_tool_calc_distance (GimpDrawTool *draw_tool,
                              GimpDisplay  *gdisp,
                              gdouble       x1,
                              gdouble       y1,
                              gdouble       x2,
                              gdouble       y2)
{
  GimpDisplayShell *shell;
  gdouble           tx1, ty1;
  gdouble           tx2, ty2;

  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), 0.0);
  g_return_val_if_fail (GIMP_IS_DISPLAY (gdisp), 0.0);

  shell = GIMP_DISPLAY_SHELL (gdisp->shell);

  gimp_display_shell_transform_xy_f (shell, x1, y1, &tx1, &ty1, FALSE);
  gimp_display_shell_transform_xy_f (shell, x2, y2, &tx2, &ty2, FALSE);

  return sqrt (SQR (tx2 - tx1) + SQR (ty2 - ty1));
}

gboolean
gimp_draw_tool_in_radius (GimpDrawTool *draw_tool,
                          GimpDisplay  *gdisp,
                          gdouble       x1,
                          gdouble       y1,
                          gdouble       x2,
                          gdouble       y2,
                          gint          radius)
{
  GimpDisplayShell *shell;
  gdouble           tx1, ty1;
  gdouble           tx2, ty2;

  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), FALSE);
  g_return_val_if_fail (GIMP_IS_DISPLAY (gdisp), FALSE);

  shell = GIMP_DISPLAY_SHELL (gdisp->shell);

  gimp_display_shell_transform_xy_f (shell, x1, y1, &tx1, &ty1, FALSE);
  gimp_display_shell_transform_xy_f (shell, x2, y2, &tx2, &ty2, FALSE);

  return (SQR (tx2 - tx1) + SQR (ty2 - ty1)) < SQR (radius);
}

void
gimp_draw_tool_draw_line (GimpDrawTool *draw_tool,
                          gdouble       x1,
                          gdouble       y1,
                          gdouble       x2,
                          gdouble       y2,
                          gboolean      use_offsets)
{
  GimpDisplayShell *shell;
  gint              tx1, ty1;
  gint              tx2, ty2;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy (shell,
                                   x1, y1,
                                   &tx1, &ty1,
                                   use_offsets);
  gimp_display_shell_transform_xy (shell,
                                   x2, y2,
                                   &tx2, &ty2,
                                   use_offsets);

  gimp_canvas_draw_line (GIMP_CANVAS (shell->canvas), GIMP_CANVAS_STYLE_XOR,
                         tx1, ty1,
                         tx2, ty2);
}

void
gimp_draw_tool_draw_dashed_line (GimpDrawTool *draw_tool,
                                 gdouble       x1,
                                 gdouble       y1,
                                 gdouble       x2,
                                 gdouble       y2,
                                 gboolean      use_offsets)
{
  GimpDisplayShell *shell;
  gint              tx1, ty1;
  gint              tx2, ty2;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy (shell,
                                   x1, y1,
                                   &tx1, &ty1,
                                   use_offsets);
  gimp_display_shell_transform_xy (shell,
                                   x2, y2,
                                   &tx2, &ty2,
                                   use_offsets);

  gimp_canvas_draw_line (GIMP_CANVAS (shell->canvas),
                         GIMP_CANVAS_STYLE_XOR_DASHED,
                         tx1, ty1,
                         tx2, ty2);
}

void
gimp_draw_tool_draw_rectangle (GimpDrawTool *draw_tool,
                               gboolean      filled,
                               gdouble       x,
                               gdouble       y,
                               gdouble       width,
                               gdouble       height,
                               gboolean      use_offsets)
{
  GimpDisplayShell *shell;
  gint              tx1, ty1;
  gint              tx2, ty2;
  guint             w, h;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy (shell,
                                   MIN (x, x + width), MIN (y, y + height),
                                   &tx1, &ty1,
                                   use_offsets);
  gimp_display_shell_transform_xy (shell,
                                   MAX (x, x + width), MAX (y, y + height),
                                   &tx2, &ty2,
                                   use_offsets);

  tx1 = CLAMP (tx1, -1, shell->disp_width + 1);
  ty1 = CLAMP (ty1, -1, shell->disp_height + 1);
  tx2 = CLAMP (tx2, -1, shell->disp_width + 1);
  ty2 = CLAMP (ty2, -1, shell->disp_height + 1);

  tx2 -= tx1;
  ty2 -= ty1;
  w = MAX (0, tx2);
  h = MAX (0, ty2);

  if (w > 0 && h > 0)
    gimp_canvas_draw_rectangle (GIMP_CANVAS (shell->canvas),
                                GIMP_CANVAS_STYLE_XOR,
                                filled,
                                tx1, ty1,
                                w - 1, h - 1);
}

void
gimp_draw_tool_draw_arc (GimpDrawTool *draw_tool,
                         gboolean      filled,
                         gdouble       x,
                         gdouble       y,
                         gdouble       width,
                         gdouble       height,
                         gint          angle1,
                         gint          angle2,
                         gboolean      use_offsets)
{
  GimpDisplayShell *shell;
  gint              tx1, ty1;
  gint              tx2, ty2;
  guint             w, h;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy (shell,
                                   MIN (x, x + width), MIN (y, y + height),
                                   &tx1, &ty1,
                                   use_offsets);
  gimp_display_shell_transform_xy (shell,
                                   MAX (x, x + width), MAX (y, y + height),
                                   &tx2, &ty2,
                                   use_offsets);

  tx2 -= tx1;
  ty2 -= ty1;
  w = MAX (0, tx2);
  h = MAX (0, ty2);

  if (w > 0 && h > 0)
    {
      if (w != 1 && h != 1)
        {
          gimp_canvas_draw_arc (GIMP_CANVAS (shell->canvas),
                                GIMP_CANVAS_STYLE_XOR,
                                filled,
                                tx1, ty1,
                                w - 1, h - 1,
                                angle1, angle2);
        }
      else
        {
          /* work around the problem of an 1xN or Nx1 arc not being shown
             properly */
          gimp_canvas_draw_rectangle (GIMP_CANVAS (shell->canvas),
                                      GIMP_CANVAS_STYLE_XOR,
                                      filled,
                                      tx1, ty1,
                                      w - 1, h - 1);
        }
    }
}

void
gimp_draw_tool_draw_rectangle_by_anchor (GimpDrawTool   *draw_tool,
                                         gboolean        filled,
                                         gdouble         x,
                                         gdouble         y,
                                         gint            width,
                                         gint            height,
                                         GtkAnchorType   anchor,
                                         gboolean        use_offsets)
{
  GimpDisplayShell *shell;
  gdouble           tx, ty;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy_f (shell,
                                     x, y,
                                     &tx, &ty,
                                     use_offsets);

  gimp_draw_tool_shift_to_north_west (tx, ty,
                                      width, height,
                                      anchor,
                                      &tx, &ty);

  if (filled)
    {
      width++;
      height++;
    }

  gimp_canvas_draw_rectangle (GIMP_CANVAS (shell->canvas),
                              GIMP_CANVAS_STYLE_XOR,
                              filled,
                              PROJ_ROUND (tx), PROJ_ROUND (ty),
                              width, height);
}

void
gimp_draw_tool_draw_arc_by_anchor (GimpDrawTool  *draw_tool,
                                   gboolean       filled,
                                   gdouble        x,
                                   gdouble        y,
                                   gint           radius_x,
                                   gint           radius_y,
                                   gint           angle1,
                                   gint           angle2,
                                   GtkAnchorType  anchor,
                                   gboolean       use_offsets)
{
  GimpDisplayShell *shell;
  gdouble           tx, ty;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy_f (shell,
                                     x, y,
                                     &tx, &ty,
                                     use_offsets);

  /* well... */
  radius_x *= 2;
  radius_y *= 2;

  gimp_draw_tool_shift_to_north_west (tx, ty,
                                      radius_x, radius_y,
                                      anchor,
                                      &tx, &ty);

  if (filled)
    {
      radius_x += 1;
      radius_y += 1;
    }

  gimp_canvas_draw_arc (GIMP_CANVAS (shell->canvas), GIMP_CANVAS_STYLE_XOR,
                        filled,
                        PROJ_ROUND (tx), PROJ_ROUND (ty),
                        radius_x, radius_y,
                        angle1, angle2);
}

void
gimp_draw_tool_draw_cross_by_anchor (GimpDrawTool  *draw_tool,
                                     gdouble        x,
                                     gdouble        y,
                                     gint           width,
                                     gint           height,
                                     GtkAnchorType  anchor,
                                     gboolean       use_offsets)
{
  GimpDisplayShell *shell;
  gdouble           tx, ty;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gimp_display_shell_transform_xy_f (shell,
                                     x, y,
                                     &tx, &ty,
                                     use_offsets);

  gimp_draw_tool_shift_to_center (tx, ty,
                                  width, height,
                                  anchor,
                                  &tx, &ty);

  gimp_canvas_draw_line (GIMP_CANVAS (shell->canvas), GIMP_CANVAS_STYLE_XOR,
                         PROJ_ROUND (tx), PROJ_ROUND (ty) - (height >> 1),
                         PROJ_ROUND (tx), PROJ_ROUND (ty) + (height >> 1));
  gimp_canvas_draw_line (GIMP_CANVAS (shell->canvas), GIMP_CANVAS_STYLE_XOR,
                         PROJ_ROUND (tx) - (width >> 1), PROJ_ROUND (ty),
                         PROJ_ROUND (tx) + (width >> 1), PROJ_ROUND (ty));
}

void
gimp_draw_tool_draw_handle (GimpDrawTool   *draw_tool,
                            GimpHandleType  type,
                            gdouble         x,
                            gdouble         y,
                            gint            width,
                            gint            height,
                            GtkAnchorType   anchor,
                            gboolean        use_offsets)
{
  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  switch (type)
    {
    case GIMP_HANDLE_SQUARE:
      gimp_draw_tool_draw_rectangle_by_anchor (draw_tool,
                                               FALSE,
                                               x, y,
                                               width,
                                               height,
                                               anchor,
                                               use_offsets);
      break;

    case GIMP_HANDLE_FILLED_SQUARE:
      gimp_draw_tool_draw_rectangle_by_anchor (draw_tool,
                                               TRUE,
                                               x, y,
                                               width,
                                               height,
                                               anchor,
                                               use_offsets);
      break;

    case GIMP_HANDLE_CIRCLE:
      gimp_draw_tool_draw_arc_by_anchor (draw_tool,
                                         FALSE,
                                         x, y,
                                         width >> 1,
                                         height >> 1,
                                         0, 360 * 64,
                                         anchor,
                                         use_offsets);
      break;

    case GIMP_HANDLE_FILLED_CIRCLE:
      gimp_draw_tool_draw_arc_by_anchor (draw_tool,
                                         TRUE,
                                         x, y,
                                         width >> 1,
                                         height >> 1,
                                         0, 360 * 64,
                                         anchor,
                                         use_offsets);
      break;

    case GIMP_HANDLE_CROSS:
      gimp_draw_tool_draw_cross_by_anchor (draw_tool,
                                           x, y,
                                           width,
                                           height,
                                           anchor,
                                           use_offsets);
      break;

    default:
      g_warning ("%s: invalid handle type %d", G_STRFUNC, type);
      break;
    }
}

gboolean
gimp_draw_tool_on_handle (GimpDrawTool   *draw_tool,
                          GimpDisplay    *gdisp,
                          gdouble         x,
                          gdouble         y,
                          GimpHandleType  type,
                          gdouble         handle_x,
                          gdouble         handle_y,
                          gint            width,
                          gint            height,
                          GtkAnchorType   anchor,
                          gboolean        use_offsets)
{
  GimpDisplayShell *shell;
  gdouble           tx, ty;
  gdouble           handle_tx, handle_ty;

  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), FALSE);
  g_return_val_if_fail (GIMP_IS_DISPLAY (gdisp), FALSE);

  shell = GIMP_DISPLAY_SHELL (gdisp->shell);

  gimp_display_shell_transform_xy_f (shell,
                                     x, y,
                                     &tx, &ty,
                                     use_offsets);
  gimp_display_shell_transform_xy_f (shell,
                                     handle_x, handle_y,
                                     &handle_tx, &handle_ty,
                                     use_offsets);

  switch (type)
    {
    case GIMP_HANDLE_SQUARE:
    case GIMP_HANDLE_FILLED_SQUARE:
    case GIMP_HANDLE_CROSS:
      gimp_draw_tool_shift_to_north_west (handle_tx, handle_ty,
                                          width, height,
                                          anchor,
                                          &handle_tx, &handle_ty);

      return (tx == CLAMP (tx, handle_tx, handle_tx + width) &&
              ty == CLAMP (ty, handle_ty, handle_ty + height));

    case GIMP_HANDLE_CIRCLE:
    case GIMP_HANDLE_FILLED_CIRCLE:
      gimp_draw_tool_shift_to_center (handle_tx, handle_ty,
                                      width, height,
                                      anchor,
                                      &handle_tx, &handle_ty);

      /* FIXME */
      if (width != height)
        width = (width + height) / 2;

      width /= 2;

      return ((SQR (handle_tx - tx) + SQR (handle_ty - ty)) < SQR (width));

    default:
      g_warning ("%s: invalid handle type %d", G_STRFUNC, type);
      break;
    }

  return FALSE;
}

gboolean
gimp_draw_tool_on_vectors_handle (GimpDrawTool    *draw_tool,
                                  GimpDisplay     *gdisp,
                                  GimpVectors     *vectors,
                                  GimpCoords      *coord,
                                  gint             width,
                                  gint             height,
                                  GimpAnchorType   preferred,
                                  gboolean         exclusive,
                                  GimpAnchor     **ret_anchor,
                                  GimpStroke     **ret_stroke)
{
  GimpStroke *stroke       = NULL;
  GimpStroke *pref_stroke  = NULL;
  GimpAnchor *anchor       = NULL;
  GimpAnchor *pref_anchor  = NULL;
  GList      *list;
  gdouble     dx, dy;
  gdouble     pref_mindist = -1;
  gdouble     mindist      = -1;

  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), FALSE);
  g_return_val_if_fail (GIMP_IS_DISPLAY (gdisp), FALSE);
  g_return_val_if_fail (GIMP_IS_VECTORS (vectors), FALSE);
  g_return_val_if_fail (coord != NULL, FALSE);

  if (ret_anchor) *ret_anchor = NULL;
  if (ret_stroke) *ret_stroke = NULL;

  while ((stroke = gimp_vectors_stroke_get_next (vectors, stroke)))
    {
      GList *anchor_list;

      anchor_list = gimp_stroke_get_draw_anchors (stroke);

      list = gimp_stroke_get_draw_controls (stroke);
      anchor_list = g_list_concat (anchor_list, list);

      while (anchor_list)
        {
          dx = coord->x - GIMP_ANCHOR (anchor_list->data)->position.x;
          dy = coord->y - GIMP_ANCHOR (anchor_list->data)->position.y;

          if (mindist < 0 || mindist > dx * dx + dy * dy)
            {
              mindist = dx * dx + dy * dy;
              anchor = GIMP_ANCHOR (anchor_list->data);
              if (ret_stroke)
                *ret_stroke = stroke;
            }

          if ((pref_mindist < 0 || pref_mindist > dx * dx + dy * dy) &&
              GIMP_ANCHOR (anchor_list->data)->type == preferred)
            {
              pref_mindist = dx * dx + dy * dy;
              pref_anchor = GIMP_ANCHOR (anchor_list->data);
              pref_stroke = stroke;
            }

          anchor_list = anchor_list->next;
        }

      g_list_free (anchor_list);
    }

  /* If the data passed into ret_anchor is a preferred anchor, return it. */
  if (ret_anchor && *ret_anchor &&
      gimp_draw_tool_on_handle (draw_tool, gdisp,
                                coord->x,
                                coord->y,
                                GIMP_HANDLE_CIRCLE,
                                (*ret_anchor)->position.x,
                                (*ret_anchor)->position.y,
                                width, height,
                                GTK_ANCHOR_CENTER,
                                FALSE) &&
      (*ret_anchor)->type == preferred)
    {
      if (ret_stroke) *ret_stroke = pref_stroke;

      return TRUE;
    }

  if (pref_anchor && gimp_draw_tool_on_handle (draw_tool, gdisp,
                                               coord->x,
                                               coord->y,
                                               GIMP_HANDLE_CIRCLE,
                                               pref_anchor->position.x,
                                               pref_anchor->position.y,
                                               width, height,
                                               GTK_ANCHOR_CENTER,
                                               FALSE))
    {
      if (ret_anchor) *ret_anchor = pref_anchor;
      if (ret_stroke) *ret_stroke = pref_stroke;

      return TRUE;
    }
  else if (!exclusive && anchor &&
           gimp_draw_tool_on_handle (draw_tool, gdisp,
                                     coord->x,
                                     coord->y,
                                     GIMP_HANDLE_CIRCLE,
                                     anchor->position.x,
                                     anchor->position.y,
                                     width, height,
                                     GTK_ANCHOR_CENTER,
                                     FALSE))
    {
      if (ret_anchor)
        *ret_anchor = anchor;

      /* *ret_stroke already set correctly. */
      return TRUE;
    }

  if (ret_anchor)
    *ret_anchor = NULL;
  if (ret_stroke)
    *ret_stroke = NULL;

  return FALSE;
}

gboolean
gimp_draw_tool_on_vectors_curve (GimpDrawTool  *draw_tool,
                                 GimpDisplay   *gdisp,
                                 GimpVectors   *vectors,
                                 GimpCoords    *coord,
                                 gint           width,
                                 gint           height,
                                 GimpCoords    *ret_coords,
                                 gdouble       *ret_pos,
                                 GimpAnchor   **ret_segment_start,
                                 GimpAnchor   **ret_segment_end,
                                 GimpStroke   **ret_stroke)
{
  GimpStroke *stroke = NULL;
  GimpAnchor *segment_start;
  GimpAnchor *segment_end;
  GimpCoords  min_coords, cur_coords;
  gdouble     min_dist, cur_dist, cur_pos;

  g_return_val_if_fail (GIMP_IS_DRAW_TOOL (draw_tool), FALSE);
  g_return_val_if_fail (GIMP_IS_DISPLAY (gdisp), FALSE);
  g_return_val_if_fail (GIMP_IS_VECTORS (vectors), FALSE);
  g_return_val_if_fail (coord != NULL, FALSE);

  if (ret_coords)        *ret_coords        = *coord;
  if (ret_pos)           *ret_pos           = -1.0;
  if (ret_segment_start) *ret_segment_start = NULL;
  if (ret_segment_start) *ret_segment_end   = NULL;
  if (ret_stroke)        *ret_stroke        = NULL;

  min_dist = -1.0;

  while ((stroke = gimp_vectors_stroke_get_next (vectors, stroke)))
    {
      cur_dist = gimp_stroke_nearest_point_get (stroke, coord, 1.0,
	                                        &cur_coords,
                                                &segment_start,
                                                &segment_end,
                                                &cur_pos);

      if (cur_dist >= 0 && (min_dist < 0 || cur_dist < min_dist))
        {
          min_dist   = cur_dist;
          min_coords = cur_coords;

          if (ret_coords)        *ret_coords        = cur_coords;
          if (ret_pos)           *ret_pos           = cur_pos;
          if (ret_segment_start) *ret_segment_start = segment_start;
          if (ret_segment_end)   *ret_segment_end   = segment_end;
          if (ret_stroke)        *ret_stroke        = stroke;
        }
    }

  if (min_dist >= 0 &&
      gimp_draw_tool_on_handle (draw_tool, gdisp,
                                coord->x,
                                coord->y,
                                GIMP_HANDLE_CIRCLE,
                                min_coords.x,
                                min_coords.y,
                                width, height,
                                GTK_ANCHOR_CENTER,
                                FALSE))
    {
      return TRUE;
    }

  return FALSE;
}

gboolean
gimp_draw_tool_on_vectors (GimpDrawTool *draw_tool,
                           GimpDisplay  *gdisp,
                           GimpCoords   *coords,
                           gint          width,
                           gint          height,
                           GimpCoords   *ret_coords,
                           gdouble      *ret_pos,
                           GimpAnchor  **ret_segment_start,
                           GimpAnchor  **ret_segment_end,
                           GimpStroke  **ret_stroke,
                           GimpVectors **ret_vectors)
{
  GList *list;

  if (ret_coords)        *ret_coords         = *coords;
  if (ret_pos)           *ret_pos            = -1.0;
  if (ret_segment_start) *ret_segment_start  = NULL;
  if (ret_segment_end)   *ret_segment_end    = NULL;
  if (ret_stroke)        *ret_stroke         = NULL;
  if (ret_vectors)       *ret_vectors        = NULL;

  for (list = GIMP_LIST (gdisp->gimage->vectors)->list;
       list;
       list = g_list_next (list))
    {
      GimpVectors *vectors = list->data;

      if (! gimp_item_get_visible (GIMP_ITEM (vectors)))
        continue;

      if (gimp_draw_tool_on_vectors_curve (draw_tool,
                                           gdisp,
                                           vectors, coords,
                                           width, height,
                                           ret_coords,
                                           ret_pos,
                                           ret_segment_start,
                                           ret_segment_end,
                                           ret_stroke))
        {
          if (ret_vectors)
            *ret_vectors = vectors;

          return TRUE;
        }
    }

  return FALSE;
}

void
gimp_draw_tool_draw_lines (GimpDrawTool *draw_tool,
			   gdouble      *points,
			   gint          n_points,
			   gboolean      filled,
                           gboolean      use_offsets)
{
  GimpDisplayShell *shell;
  GdkPoint         *coords;
  gint              i;
  gint              sx, sy;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  coords = g_new (GdkPoint, n_points);

  for (i = 0; i < n_points ; i++)
    {
      gimp_display_shell_transform_xy (shell,
                                       points[i*2], points[i*2+1],
                                       &sx, &sy,
                                       use_offsets);
      coords[i].x = sx;
      coords[i].y = sy;
    }

  if (filled)
    {
      gimp_canvas_draw_polygon (GIMP_CANVAS (shell->canvas),
                                GIMP_CANVAS_STYLE_XOR,
                                TRUE, coords, n_points);
    }
  else
    {
      gimp_canvas_draw_lines (GIMP_CANVAS (shell->canvas),
                              GIMP_CANVAS_STYLE_XOR,
                              coords, n_points);
    }

  g_free (coords);
}

void
gimp_draw_tool_draw_strokes (GimpDrawTool *draw_tool,
			     GimpCoords   *points,
			     gint          n_points,
			     gboolean      filled,
                             gboolean      use_offsets)
{
  GimpDisplayShell *shell;
  GdkPoint         *coords;
  gint              i;
  gint              sx, sy;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  coords = g_new (GdkPoint, n_points);

  for (i = 0; i < n_points ; i++)
    {
      gimp_display_shell_transform_xy (shell,
                                       points[i].x, points[i].y,
                                       &sx, &sy,
                                       use_offsets);
      coords[i].x = sx;
      coords[i].y = sy;
    }

  if (filled)
    {
      gimp_canvas_draw_polygon (GIMP_CANVAS (shell->canvas),
                                GIMP_CANVAS_STYLE_XOR,
                                TRUE, coords, n_points);
    }
  else
    {
      gimp_canvas_draw_lines (GIMP_CANVAS (shell->canvas),
                              GIMP_CANVAS_STYLE_XOR,
                              coords, n_points);
    }

  g_free (coords);
}

void
gimp_draw_tool_draw_boundary (GimpDrawTool   *draw_tool,
                              const BoundSeg *bound_segs,
                              gint            n_bound_segs,
                              gdouble         offset_x,
                              gdouble         offset_y,
                              gboolean        use_offsets)
{
  GimpDisplayShell *shell;
  GdkSegment       *gdk_segs;
  gint              n_gdk_segs;
  gint              xmax, ymax;
  gint              x, y;
  gint              i;

  g_return_if_fail (GIMP_IS_DRAW_TOOL (draw_tool));
  g_return_if_fail (n_bound_segs > 0 || bound_segs == NULL);

  shell = GIMP_DISPLAY_SHELL (draw_tool->gdisp->shell);

  gdk_segs   = g_new0 (GdkSegment, n_bound_segs);
  n_gdk_segs = 0;

  xmax = shell->disp_width  + 1;
  ymax = shell->disp_height + 1;

  for (i = 0; i < n_bound_segs; i++)
    {
      gimp_display_shell_transform_xy (shell,
                                       bound_segs[i].x1 + offset_x,
                                       bound_segs[i].y1 + offset_y,
                                       &x, &y,
                                       use_offsets);

      gdk_segs[n_gdk_segs].x1 = CLAMP (x, -1, xmax);
      gdk_segs[n_gdk_segs].y1 = CLAMP (y, -1, ymax);

      gimp_display_shell_transform_xy (shell,
                                       bound_segs[i].x2 + offset_x,
                                       bound_segs[i].y2 + offset_y,
                                       &x, &y,
                                       use_offsets);

      gdk_segs[n_gdk_segs].x2 = CLAMP (x, -1, xmax);
      gdk_segs[n_gdk_segs].y2 = CLAMP (y, -1, ymax);

      if (gdk_segs[n_gdk_segs].x1 == gdk_segs[n_gdk_segs].x2 &&
          gdk_segs[n_gdk_segs].y1 == gdk_segs[n_gdk_segs].y2)
        continue;

      /*  If this segment is a closing segment && the segments lie inside
       *  the region, OR if this is an opening segment and the segments
       *  lie outside the region...
       *  we need to transform it by one display pixel
       */
      if (! bound_segs[i].open)
        {
          /*  If it is vertical  */
          if (gdk_segs[n_gdk_segs].x1 == gdk_segs[n_gdk_segs].x2)
            {
              gdk_segs[n_gdk_segs].x1 -= 1;
              gdk_segs[n_gdk_segs].x2 -= 1;
            }
          else
            {
              gdk_segs[n_gdk_segs].y1 -= 1;
              gdk_segs[n_gdk_segs].y2 -= 1;
            }
        }

      n_gdk_segs++;
    }

  gimp_canvas_draw_segments (GIMP_CANVAS (shell->canvas),
                             GIMP_CANVAS_STYLE_XOR,
                             gdk_segs, n_gdk_segs);

  g_free (gdk_segs);
}


/*  private functions  */

static inline void
gimp_draw_tool_shift_to_north_west (gdouble        x,
                                    gdouble        y,
                                    gint           handle_width,
                                    gint           handle_height,
                                    GtkAnchorType  anchor,
                                    gdouble       *shifted_x,
                                    gdouble       *shifted_y)
{
  switch (anchor)
    {
    case GTK_ANCHOR_CENTER:
      x -= (handle_width >> 1);
      y -= (handle_height >> 1);
      break;

    case GTK_ANCHOR_NORTH:
      x -= (handle_width >> 1);
      break;

    case GTK_ANCHOR_NORTH_WEST:
      /*  nothing, this is the default  */
      break;

    case GTK_ANCHOR_NORTH_EAST:
      x -= handle_width;
      break;

    case GTK_ANCHOR_SOUTH:
      x -= (handle_width >> 1);
      y -= handle_height;
      break;

    case GTK_ANCHOR_SOUTH_WEST:
      y -= handle_height;
      break;

    case GTK_ANCHOR_SOUTH_EAST:
      x -= handle_width;
      y -= handle_height;
      break;

    case GTK_ANCHOR_WEST:
      y -= (handle_height >> 1);
      break;

    case GTK_ANCHOR_EAST:
      x -= handle_width;
      y -= (handle_height >> 1);
      break;

    default:
      break;
    }

  if (shifted_x)
    *shifted_x = x;

  if (shifted_y)
    *shifted_y = y;
}

static inline void
gimp_draw_tool_shift_to_center (gdouble        x,
                                gdouble        y,
                                gint           handle_width,
                                gint           handle_height,
                                GtkAnchorType  anchor,
                                gdouble       *shifted_x,
                                gdouble       *shifted_y)
{
  switch (anchor)
    {
    case GTK_ANCHOR_CENTER:
      /*  nothing, this is the default  */
      break;

    case GTK_ANCHOR_NORTH:
      y += (handle_height >> 1);
      break;

    case GTK_ANCHOR_NORTH_WEST:
      x += (handle_width >> 1);
      y += (handle_height >> 1);
      break;

    case GTK_ANCHOR_NORTH_EAST:
      x -= (handle_width >> 1);
      y += (handle_height >> 1);
      break;

    case GTK_ANCHOR_SOUTH:
      y -= (handle_height >> 1);
      break;

    case GTK_ANCHOR_SOUTH_WEST:
      x += (handle_width >> 1);
      y -= (handle_height >> 1);
      break;

    case GTK_ANCHOR_SOUTH_EAST:
      x -= (handle_width >> 1);
      y -= (handle_height >> 1);
      break;

    case GTK_ANCHOR_WEST:
      x += (handle_width >> 1);
      break;

    case GTK_ANCHOR_EAST:
      x -= (handle_width >> 1);
      break;

    default:
      break;
    }

  if (shifted_x)
    *shifted_x = x;

  if (shifted_y)
    *shifted_y = y;
}