Adding upstream version 2.10.22.upstream/2.10.22upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1547 insertions, 0 deletions

diff --git a/app/widgets/gimpcurveview.c b/app/widgets/gimpcurveview.c
new file mode 100644
index 0000000..c34d06e
--- /dev/null
+++ b/app/widgets/gimpcurveview.c
@@ -0,0 +1,1547 @@
+/* GIMP - The GNU 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 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 <https://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 "libgimpcolor/gimpcolor.h"
+#include "libgimpconfig/gimpconfig.h"
+#include "libgimpwidgets/gimpwidgets.h"
+
+#include "widgets-types.h"
+
+#include "core/gimp.h"
+#include "core/gimpcurve.h"
+#include "core/gimpcurve-map.h"
+#include "core/gimpmarshal.h"
+
+#include "gimpclipboard.h"
+#include "gimpcurveview.h"
+#include "gimpwidgets-utils.h"
+
+
+#define POINT_MAX_DISTANCE 16.0
+
+
+enum
+{
+  PROP_0,
+  PROP_GIMP,
+  PROP_BASE_LINE,
+  PROP_GRID_ROWS,
+  PROP_GRID_COLUMNS,
+  PROP_X_AXIS_LABEL,
+  PROP_Y_AXIS_LABEL
+};
+
+enum
+{
+  SELECTION_CHANGED,
+  CUT_CLIPBOARD,
+  COPY_CLIPBOARD,
+  PASTE_CLIPBOARD,
+  LAST_SIGNAL
+};
+
+
+typedef struct
+{
+  GimpCurve *curve;
+  GimpRGB    color;
+  gboolean   color_set;
+} BGCurve;
+
+
+static void       gimp_curve_view_finalize              (GObject          *object);
+static void       gimp_curve_view_dispose               (GObject          *object);
+static void       gimp_curve_view_set_property          (GObject          *object,
+                                                         guint             property_id,
+                                                         const GValue     *value,
+                                                         GParamSpec       *pspec);
+static void       gimp_curve_view_get_property          (GObject          *object,
+                                                         guint             property_id,
+                                                         GValue           *value,
+                                                         GParamSpec       *pspec);
+
+static void       gimp_curve_view_style_set             (GtkWidget        *widget,
+                                                         GtkStyle         *prev_style);
+static gboolean   gimp_curve_view_expose                (GtkWidget        *widget,
+                                                         GdkEventExpose   *event);
+static gboolean   gimp_curve_view_button_press          (GtkWidget        *widget,
+                                                         GdkEventButton   *bevent);
+static gboolean   gimp_curve_view_button_release        (GtkWidget        *widget,
+                                                         GdkEventButton   *bevent);
+static gboolean   gimp_curve_view_motion_notify         (GtkWidget        *widget,
+                                                         GdkEventMotion   *bevent);
+static gboolean   gimp_curve_view_leave_notify          (GtkWidget        *widget,
+                                                         GdkEventCrossing *cevent);
+static gboolean   gimp_curve_view_key_press             (GtkWidget        *widget,
+                                                         GdkEventKey      *kevent);
+
+static void       gimp_curve_view_cut_clipboard         (GimpCurveView    *view);
+static void       gimp_curve_view_copy_clipboard        (GimpCurveView    *view);
+static void       gimp_curve_view_paste_clipboard       (GimpCurveView    *view);
+
+static void       gimp_curve_view_curve_dirty           (GimpCurve        *curve,
+                                                         GimpCurveView    *view);
+static void       gimp_curve_view_curve_notify_n_points (GimpCurve        *curve,
+                                                         GParamSpec       *pspec,
+                                                         GimpCurveView    *view);
+
+static void       gimp_curve_view_set_cursor            (GimpCurveView    *view,
+                                                         gdouble           x,
+                                                         gdouble           y);
+static void       gimp_curve_view_unset_cursor          (GimpCurveView *view);
+
+
+G_DEFINE_TYPE (GimpCurveView, gimp_curve_view,
+               GIMP_TYPE_HISTOGRAM_VIEW)
+
+#define parent_class gimp_curve_view_parent_class
+
+static guint curve_view_signals[LAST_SIGNAL] = { 0 };
+
+
+static void
+gimp_curve_view_class_init (GimpCurveViewClass *klass)
+{
+  GObjectClass   *object_class = G_OBJECT_CLASS (klass);
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+  GtkBindingSet  *binding_set;
+
+  object_class->finalize             = gimp_curve_view_finalize;
+  object_class->dispose              = gimp_curve_view_dispose;
+  object_class->set_property         = gimp_curve_view_set_property;
+  object_class->get_property         = gimp_curve_view_get_property;
+
+  widget_class->style_set            = gimp_curve_view_style_set;
+  widget_class->expose_event         = gimp_curve_view_expose;
+  widget_class->button_press_event   = gimp_curve_view_button_press;
+  widget_class->button_release_event = gimp_curve_view_button_release;
+  widget_class->motion_notify_event  = gimp_curve_view_motion_notify;
+  widget_class->leave_notify_event   = gimp_curve_view_leave_notify;
+  widget_class->key_press_event      = gimp_curve_view_key_press;
+
+  klass->selection_changed           = NULL;
+  klass->cut_clipboard               = gimp_curve_view_cut_clipboard;
+  klass->copy_clipboard              = gimp_curve_view_copy_clipboard;
+  klass->paste_clipboard             = gimp_curve_view_paste_clipboard;
+
+  g_object_class_install_property (object_class, PROP_GIMP,
+                                   g_param_spec_object ("gimp",
+                                                        NULL, NULL,
+                                                        GIMP_TYPE_GIMP,
+                                                        GIMP_PARAM_READWRITE));
+
+  g_object_class_install_property (object_class, PROP_BASE_LINE,
+                                   g_param_spec_boolean ("base-line",
+                                                         NULL, NULL,
+                                                         TRUE,
+                                                         GIMP_PARAM_READWRITE |
+                                                         G_PARAM_CONSTRUCT_ONLY));
+
+  g_object_class_install_property (object_class, PROP_GRID_ROWS,
+                                   g_param_spec_int ("grid-rows", NULL, NULL,
+                                                     0, 100, 8,
+                                                     GIMP_PARAM_READWRITE |
+                                                     G_PARAM_CONSTRUCT_ONLY));
+
+  g_object_class_install_property (object_class, PROP_GRID_COLUMNS,
+                                   g_param_spec_int ("grid-columns", NULL, NULL,
+                                                     0, 100, 8,
+                                                     GIMP_PARAM_READWRITE |
+                                                     G_PARAM_CONSTRUCT_ONLY));
+
+  g_object_class_install_property (object_class, PROP_X_AXIS_LABEL,
+                                   g_param_spec_string ("x-axis-label", NULL, NULL,
+                                                        NULL,
+                                                        GIMP_PARAM_READWRITE));
+
+  g_object_class_install_property (object_class, PROP_Y_AXIS_LABEL,
+                                   g_param_spec_string ("y-axis-label", NULL, NULL,
+                                                        NULL,
+                                                        GIMP_PARAM_READWRITE));
+
+  curve_view_signals[SELECTION_CHANGED] =
+    g_signal_new ("selection-changed",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_FIRST,
+                  G_STRUCT_OFFSET (GimpCurveViewClass, selection_changed),
+                  NULL, NULL,
+                  gimp_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
+  curve_view_signals[CUT_CLIPBOARD] =
+    g_signal_new ("cut-clipboard",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+                  G_STRUCT_OFFSET (GimpCurveViewClass, cut_clipboard),
+                  NULL, NULL,
+                  gimp_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
+  curve_view_signals[COPY_CLIPBOARD] =
+    g_signal_new ("copy-clipboard",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+                  G_STRUCT_OFFSET (GimpCurveViewClass, copy_clipboard),
+                  NULL, NULL,
+                  gimp_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
+  curve_view_signals[PASTE_CLIPBOARD] =
+    g_signal_new ("paste-clipboard",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+                  G_STRUCT_OFFSET (GimpCurveViewClass, paste_clipboard),
+                  NULL, NULL,
+                  gimp_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
+  binding_set = gtk_binding_set_by_class (klass);
+
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_x, GDK_CONTROL_MASK,
+                                "cut-clipboard", 0);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_c, GDK_CONTROL_MASK,
+                                "copy-clipboard", 0);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_v, GDK_CONTROL_MASK,
+                                "paste-clipboard", 0);
+}
+
+static void
+gimp_curve_view_init (GimpCurveView *view)
+{
+  view->curve       = NULL;
+  view->selected    = -1;
+  view->offset_x    = 0.0;
+  view->offset_y    = 0.0;
+  view->last_x      = 0.0;
+  view->last_y      = 0.0;
+  view->cursor_type = -1;
+  view->xpos        = -1.0;
+  view->cursor_x    = -1.0;
+  view->cursor_y    = -1.0;
+  view->range_x_min = 0.0;
+  view->range_x_max = 1.0;
+  view->range_y_min = 0.0;
+  view->range_y_max = 1.0;
+
+  view->x_axis_label = NULL;
+  view->y_axis_label = NULL;
+
+  gtk_widget_set_can_focus (GTK_WIDGET (view), TRUE);
+  gtk_widget_add_events (GTK_WIDGET (view),
+                         GDK_BUTTON_PRESS_MASK   |
+                         GDK_BUTTON_RELEASE_MASK |
+                         GDK_BUTTON1_MOTION_MASK |
+                         GDK_POINTER_MOTION_MASK |
+                         GDK_KEY_PRESS_MASK      |
+                         GDK_LEAVE_NOTIFY_MASK);
+}
+
+static void
+gimp_curve_view_finalize (GObject *object)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (object);
+
+  g_clear_object (&view->orig_curve);
+
+  g_clear_object (&view->layout);
+  g_clear_object (&view->cursor_layout);
+
+  g_clear_pointer (&view->x_axis_label, g_free);
+  g_clear_pointer (&view->y_axis_label, g_free);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gimp_curve_view_dispose (GObject *object)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (object);
+
+  gimp_curve_view_set_curve (view, NULL, NULL);
+
+  if (view->bg_curves)
+    gimp_curve_view_remove_all_backgrounds (view);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+gimp_curve_view_set_property (GObject      *object,
+                              guint         property_id,
+                              const GValue *value,
+                              GParamSpec   *pspec)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (object);
+
+  switch (property_id)
+    {
+    case PROP_GIMP:
+      view->gimp = g_value_get_object (value); /* don't ref */
+      break;
+    case PROP_GRID_ROWS:
+      view->grid_rows = g_value_get_int (value);
+      break;
+    case PROP_GRID_COLUMNS:
+      view->grid_columns = g_value_get_int (value);
+      break;
+    case PROP_BASE_LINE:
+      view->draw_base_line = g_value_get_boolean (value);
+      break;
+    case PROP_X_AXIS_LABEL:
+      gimp_curve_view_set_x_axis_label (view, g_value_get_string (value));
+      break;
+    case PROP_Y_AXIS_LABEL:
+      gimp_curve_view_set_y_axis_label (view, g_value_get_string (value));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_curve_view_get_property (GObject    *object,
+                              guint       property_id,
+                              GValue     *value,
+                              GParamSpec *pspec)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (object);
+
+  switch (property_id)
+    {
+    case PROP_GIMP:
+      g_value_set_object (value, view->gimp);
+      break;
+    case PROP_GRID_ROWS:
+      g_value_set_int (value, view->grid_rows);
+      break;
+    case PROP_GRID_COLUMNS:
+      g_value_set_int (value, view->grid_columns);
+      break;
+    case PROP_BASE_LINE:
+      g_value_set_boolean (value, view->draw_base_line);
+      break;
+    case PROP_X_AXIS_LABEL:
+      g_value_set_string (value, view->x_axis_label);
+      break;
+    case PROP_Y_AXIS_LABEL:
+      g_value_set_string (value, view->y_axis_label);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_curve_view_style_set (GtkWidget *widget,
+                           GtkStyle  *prev_style)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (widget);
+
+  GTK_WIDGET_CLASS (parent_class)->style_set (widget, prev_style);
+
+  g_clear_object (&view->layout);
+  g_clear_object (&view->cursor_layout);
+}
+
+static void
+gimp_curve_view_draw_grid (GimpCurveView *view,
+                           cairo_t       *cr,
+                           gint           width,
+                           gint           height,
+                           gint           border)
+{
+  gint i;
+
+  for (i = 1; i < view->grid_rows; i++)
+    {
+      gint y = i * (height - 1) / view->grid_rows;
+
+      if ((view->grid_rows % 2) == 0 && (i == view->grid_rows / 2))
+        continue;
+
+      cairo_move_to (cr, border,             border + y);
+      cairo_line_to (cr, border + width - 1, border + y);
+    }
+
+  for (i = 1; i < view->grid_columns; i++)
+    {
+      gint x = i * (width - 1) / view->grid_columns;
+
+      if ((view->grid_columns % 2) == 0 && (i == view->grid_columns / 2))
+        continue;
+
+      cairo_move_to (cr, border + x, border);
+      cairo_line_to (cr, border + x, border + height - 1);
+    }
+
+  if (view->draw_base_line)
+    {
+      cairo_move_to (cr, border, border + height - 1);
+      cairo_line_to (cr, border + width - 1, border);
+    }
+
+  cairo_set_line_width (cr, 0.6);
+  cairo_stroke (cr);
+
+  if ((view->grid_rows % 2) == 0)
+    {
+      gint y = (height - 1) / 2;
+
+      cairo_move_to (cr, border,             border + y);
+      cairo_line_to (cr, border + width - 1, border + y);
+    }
+
+  if ((view->grid_columns % 2) == 0)
+    {
+      gint x = (width - 1) / 2;
+
+      cairo_move_to (cr, border + x, border);
+      cairo_line_to (cr, border + x, border + height - 1);
+    }
+
+  cairo_set_line_width (cr, 1.0);
+  cairo_stroke (cr);
+}
+
+static void
+gimp_curve_view_draw_point (GimpCurveView *view,
+                            cairo_t       *cr,
+                            gint           i,
+                            gint           width,
+                            gint           height,
+                            gint           border)
+{
+  gdouble x, y;
+
+  gimp_curve_get_point (view->curve, i, &x, &y);
+
+  y = 1.0 - y;
+
+#define CIRCLE_RADIUS  3
+#define DIAMOND_RADIUS (G_SQRT2 * CIRCLE_RADIUS)
+
+  switch (gimp_curve_get_point_type (view->curve, i))
+    {
+    case GIMP_CURVE_POINT_SMOOTH:
+      cairo_move_to (cr,
+                     border + (gdouble) (width  - 1) * x + CIRCLE_RADIUS,
+                     border + (gdouble) (height - 1) * y);
+      cairo_arc     (cr,
+                     border + (gdouble) (width  - 1) * x,
+                     border + (gdouble) (height - 1) * y,
+                     CIRCLE_RADIUS,
+                     0, 2 * G_PI);
+      break;
+
+    case GIMP_CURVE_POINT_CORNER:
+      cairo_move_to    (cr,
+                        border + (gdouble) (width  - 1) * x,
+                        border + (gdouble) (height - 1) * y - DIAMOND_RADIUS);
+      cairo_line_to    (cr,
+                        border + (gdouble) (width  - 1) * x + DIAMOND_RADIUS,
+                        border + (gdouble) (height - 1) * y);
+      cairo_line_to    (cr,
+                        border + (gdouble) (width  - 1) * x,
+                        border + (gdouble) (height - 1) * y + DIAMOND_RADIUS);
+      cairo_line_to    (cr,
+                        border + (gdouble) (width  - 1) * x - DIAMOND_RADIUS,
+                        border + (gdouble) (height - 1) * y);
+      cairo_close_path (cr);
+      break;
+    }
+}
+
+static void
+gimp_curve_view_draw_curve (GimpCurveView *view,
+                            cairo_t       *cr,
+                            GimpCurve     *curve,
+                            gint           width,
+                            gint           height,
+                            gint           border)
+{
+  gdouble x, y;
+  gint    i;
+
+  x = 0.0;
+  y = 1.0 - gimp_curve_map_value (curve, 0.0);
+
+  cairo_move_to (cr,
+                 border + (gdouble) (width  - 1) * x,
+                 border + (gdouble) (height - 1)* y);
+
+  for (i = 1; i < 256; i++)
+    {
+      x = (gdouble) i / 255.0;
+      y = 1.0 - gimp_curve_map_value (curve, x);
+
+      cairo_line_to (cr,
+                     border + (gdouble) (width  - 1) * x,
+                     border + (gdouble) (height - 1) * y);
+    }
+
+  cairo_stroke (cr);
+}
+
+static gboolean
+gimp_curve_view_expose (GtkWidget      *widget,
+                        GdkEventExpose *event)
+{
+  GimpCurveView *view   = GIMP_CURVE_VIEW (widget);
+  GdkWindow     *window = gtk_widget_get_window (widget);
+  GtkStyle      *style  = gtk_widget_get_style (widget);
+  GtkAllocation  allocation;
+  cairo_t       *cr;
+  GList         *list;
+  gint           border;
+  gint           width;
+  gint           height;
+  gint           layout_x;
+  gint           layout_y;
+  gdouble        x, y;
+  gint           i;
+
+  GTK_WIDGET_CLASS (parent_class)->expose_event (widget, event);
+
+  if (! view->curve)
+    return FALSE;
+
+  gtk_widget_get_allocation (widget, &allocation);
+
+  border = GIMP_HISTOGRAM_VIEW (view)->border_width;
+  width  = allocation.width  - 2 * border;
+  height = allocation.height - 2 * border;
+
+  cr = gdk_cairo_create (gtk_widget_get_window (widget));
+
+  gdk_cairo_region (cr, event->region);
+  cairo_clip (cr);
+
+  if (gtk_widget_has_focus (widget))
+    {
+      gtk_paint_focus (style, window,
+                       gtk_widget_get_state (widget),
+                       &event->area, widget, NULL,
+                       border - 2, border - 2,
+                       width + 4, height + 4);
+    }
+
+  cairo_set_line_width (cr, 1.0);
+  cairo_set_line_cap (cr, CAIRO_LINE_CAP_SQUARE);
+  cairo_translate (cr, 0.5, 0.5);
+
+  /*  Draw the grid lines  */
+  gdk_cairo_set_source_color (cr, &style->text_aa[GTK_STATE_NORMAL]);
+
+  gimp_curve_view_draw_grid (view, cr, width, height, border);
+
+  /*  Draw the axis labels  */
+
+  if (view->x_axis_label)
+    {
+      if (! view->layout)
+        view->layout = gtk_widget_create_pango_layout (widget, NULL);
+
+      pango_layout_set_text (view->layout, view->x_axis_label, -1);
+      pango_layout_get_pixel_size (view->layout, &layout_x, &layout_y);
+
+      cairo_move_to (cr,
+                     width - border - layout_x,
+                     height - border - layout_y);
+
+      gdk_cairo_set_source_color (cr, &style->text[GTK_STATE_NORMAL]);
+      pango_cairo_show_layout (cr, view->layout);
+    }
+
+  if (view->y_axis_label)
+    {
+      if (! view->layout)
+        view->layout = gtk_widget_create_pango_layout (widget, NULL);
+
+      pango_layout_set_text (view->layout, view->y_axis_label, -1);
+      pango_layout_get_pixel_size (view->layout, &layout_x, &layout_y);
+
+      cairo_save (cr);
+
+      cairo_move_to (cr,
+                     2 * border,
+                     2 * border + layout_x);
+      cairo_rotate (cr, - G_PI / 2);
+
+      gdk_cairo_set_source_color (cr, &style->text[GTK_STATE_NORMAL]);
+      pango_cairo_show_layout (cr, view->layout);
+
+      cairo_restore (cr);
+    }
+
+
+  /*  Draw the background curves  */
+  for (list = view->bg_curves; list; list = g_list_next (list))
+    {
+      BGCurve *bg = list->data;
+
+      if (bg->color_set)
+        {
+          cairo_set_source_rgba (cr,
+                                 bg->color.r,
+                                 bg->color.g,
+                                 bg->color.b,
+                                 0.5);
+        }
+      else
+        {
+          cairo_set_source_rgba (cr,
+                                 style->text[GTK_STATE_NORMAL].red / 65535.0,
+                                 style->text[GTK_STATE_NORMAL].green / 65535.0,
+                                 style->text[GTK_STATE_NORMAL].blue / 65535.0,
+                                 0.5);
+        }
+
+      gimp_curve_view_draw_curve (view, cr, bg->curve,
+                                  width, height, border);
+    }
+
+  /*  Draw the curve  */
+  if (view->curve_color)
+    gimp_cairo_set_source_rgb (cr, view->curve_color);
+  else
+    gdk_cairo_set_source_color (cr, &style->text[GTK_STATE_NORMAL]);
+
+  gimp_curve_view_draw_curve (view, cr, view->curve,
+                              width, height, border);
+
+  /*  Draw the points  */
+  if (gimp_curve_get_curve_type (view->curve) == GIMP_CURVE_SMOOTH)
+    {
+      gdk_cairo_set_source_color (cr, &style->text[GTK_STATE_NORMAL]);
+
+      /*  Draw the unselected points  */
+      for (i = 0; i < view->curve->n_points; i++)
+        {
+          if (i == view->selected)
+            continue;
+
+          gimp_curve_view_draw_point (view, cr, i, width, height, border);
+        }
+
+      cairo_stroke (cr);
+
+      /*  Draw the selected point  */
+      if (view->selected != -1)
+        {
+          gimp_curve_view_draw_point (view, cr, view->selected,
+                                      width, height, border);
+          cairo_fill (cr);
+       }
+    }
+
+  if (view->xpos >= 0.0)
+    {
+      gchar buf[32];
+
+      gdk_cairo_set_source_color (cr, &style->text[GTK_STATE_NORMAL]);
+
+      /* draw the color line */
+      cairo_move_to (cr,
+                     border + ROUND ((gdouble) (width - 1) * view->xpos),
+                     border + 1);
+      cairo_line_to (cr,
+                     border + ROUND ((gdouble) (width - 1) * view->xpos),
+                     border + height - 1);
+      cairo_stroke (cr);
+
+      if (view->range_x_max == 255.0)
+        {
+          /*  stupid heuristic: special-case for 0..255  */
+
+          g_snprintf (buf, sizeof (buf), "x:%3d",
+                      (gint) (view->xpos *
+                              (view->range_x_max - view->range_x_min) +
+                              view->range_x_min));
+        }
+      else if (view->range_x_max == 100.0)
+        {
+          /*  and for 0..100  */
+
+          g_snprintf (buf, sizeof (buf), "x:%0.2f",
+                      view->xpos *
+                      (view->range_x_max - view->range_x_min) +
+                      view->range_x_min);
+        }
+      else
+        {
+          g_snprintf (buf, sizeof (buf), "x:%0.3f",
+                      view->xpos *
+                      (view->range_x_max - view->range_x_min) +
+                      view->range_x_min);
+        }
+
+      if (! view->layout)
+        view->layout = gtk_widget_create_pango_layout (widget, NULL);
+
+      pango_layout_set_text (view->layout, buf, -1);
+      pango_layout_get_pixel_size (view->layout, &layout_x, &layout_y);
+
+      if (view->xpos < 0.5)
+        layout_x = border;
+      else
+        layout_x = -(layout_x + border);
+
+      cairo_move_to (cr,
+                     border + (gdouble) width * view->xpos + layout_x,
+                     border + height - border - layout_y);
+      pango_cairo_show_layout (cr, view->layout);
+    }
+
+  if (view->cursor_x >= 0.0 && view->cursor_x <= 1.0 &&
+      view->cursor_y >= 0.0 && view->cursor_y <= 1.0)
+    {
+      gchar  buf[32];
+      gint   w, h;
+
+      if (! view->cursor_layout)
+        view->cursor_layout = gtk_widget_create_pango_layout (widget, NULL);
+
+      if (view->range_x_max == 255.0 &&
+          view->range_y_max == 255.0)
+        {
+          /*  stupid heuristic: special-case for 0..255  */
+
+          g_snprintf (buf, sizeof (buf), "x:%3d y:%3d",
+                      (gint) round (view->cursor_x *
+                                    (view->range_x_max - view->range_x_min) +
+                                    view->range_x_min),
+                      (gint) round ((1.0 - view->cursor_y) *
+                                    (view->range_y_max - view->range_y_min) +
+                                    view->range_y_min));
+        }
+      else if (view->range_x_max == 100.0 &&
+               view->range_y_max == 100.0)
+        {
+          /*  and for 0..100  */
+
+          g_snprintf (buf, sizeof (buf), "x:%0.2f y:%0.2f",
+                      view->cursor_x *
+                      (view->range_x_max - view->range_x_min) +
+                      view->range_x_min,
+                      (1.0 - view->cursor_y) *
+                      (view->range_y_max - view->range_y_min) +
+                      view->range_y_min);
+        }
+      else
+        {
+          g_snprintf (buf, sizeof (buf), "x:%0.3f y:%0.3f",
+                      view->cursor_x *
+                      (view->range_x_max - view->range_x_min) +
+                      view->range_x_min,
+                      (1.0 - view->cursor_y) *
+                      (view->range_y_max - view->range_y_min) +
+                      view->range_y_min);
+        }
+
+      pango_layout_set_text (view->cursor_layout, buf, -1);
+      pango_layout_get_pixel_extents (view->cursor_layout,
+                                      NULL, &view->cursor_rect);
+
+      x = border * 2 + 3;
+      y = border * 2 + 3;
+      w = view->cursor_rect.width;
+      h = view->cursor_rect.height;
+
+      if (view->x_axis_label)
+        x += border + view->cursor_rect.height; /* coincidentially the right value */
+
+      cairo_push_group (cr);
+
+      gdk_cairo_set_source_color (cr, &style->text[GTK_STATE_NORMAL]);
+      cairo_rectangle (cr, x + 0.5, y + 0.5, w, h);
+      cairo_fill_preserve (cr);
+
+      cairo_set_line_width (cr, 6);
+      cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
+      cairo_stroke (cr);
+
+      gdk_cairo_set_source_color (cr, &style->base[GTK_STATE_NORMAL]);
+      cairo_move_to (cr, x, y);
+      pango_cairo_show_layout (cr, view->cursor_layout);
+
+      cairo_pop_group_to_source (cr);
+      cairo_paint_with_alpha (cr, 0.6);
+    }
+
+  cairo_destroy (cr);
+
+  return FALSE;
+}
+
+static void
+set_cursor (GimpCurveView *view,
+            GdkCursorType  new_cursor)
+{
+  if (new_cursor != view->cursor_type)
+    {
+      GdkDisplay *display = gtk_widget_get_display (GTK_WIDGET (view));
+      GdkCursor  *cursor  = gdk_cursor_new_for_display (display, new_cursor);
+
+      gdk_window_set_cursor (gtk_widget_get_window (GTK_WIDGET (view)), cursor);
+      gdk_cursor_unref (cursor);
+
+      view->cursor_type = new_cursor;
+    }
+}
+
+static gboolean
+gimp_curve_view_button_press (GtkWidget      *widget,
+                              GdkEventButton *bevent)
+{
+  GimpCurveView *view  = GIMP_CURVE_VIEW (widget);
+  GimpCurve     *curve = view->curve;
+  GtkAllocation  allocation;
+  gint           border;
+  gint           width, height;
+  gdouble        x;
+  gdouble        y;
+  gint           point;
+  gdouble        point_x;
+  gdouble        point_y;
+
+  if (! curve || bevent->button != 1)
+    return TRUE;
+
+  gtk_widget_get_allocation (widget, &allocation);
+
+  border = GIMP_HISTOGRAM_VIEW (view)->border_width;
+  width  = allocation.width  - 2 * border;
+  height = allocation.height - 2 * border;
+
+  x = (gdouble) (bevent->x - border) / (gdouble) width;
+  y = (gdouble) (bevent->y - border) / (gdouble) height;
+
+  x = CLAMP (x, 0.0, 1.0);
+  y = CLAMP (y, 0.0, 1.0);
+
+  view->grabbed = TRUE;
+
+  view->orig_curve = GIMP_CURVE (gimp_data_duplicate (GIMP_DATA (curve)));
+
+  set_cursor (view, GDK_TCROSS);
+
+  switch (gimp_curve_get_curve_type (curve))
+    {
+    case GIMP_CURVE_SMOOTH:
+      point = gimp_curve_get_closest_point (curve, x, 1.0 - y,
+                                            POINT_MAX_DISTANCE /
+                                            MAX (width, height));
+
+      if (point < 0)
+        {
+          GimpCurvePointType type = GIMP_CURVE_POINT_SMOOTH;
+
+          if (bevent->state & gimp_get_constrain_behavior_mask ())
+            y = 1.0 - gimp_curve_map_value (view->orig_curve, x);
+
+          if (view->selected >= 0)
+            type = gimp_curve_get_point_type (curve, view->selected);
+
+          point = gimp_curve_add_point (curve, x, 1.0 - y);
+
+          gimp_curve_set_point_type (curve, point, type);
+        }
+
+      if (point > 0)
+        gimp_curve_get_point (curve, point - 1, &view->leftmost, NULL);
+      else
+        view->leftmost = -1.0;
+
+      if (point < gimp_curve_get_n_points (curve) - 1)
+        gimp_curve_get_point (curve, point + 1, &view->rightmost, NULL);
+      else
+        view->rightmost = 2.0;
+
+      gimp_curve_view_set_selected (view, point);
+
+      gimp_curve_get_point (curve, point, &point_x, &point_y);
+
+      view->offset_x = point_x         - x;
+      view->offset_y = (1.0 - point_y) - y;
+
+      view->point_type = gimp_curve_get_point_type (curve, point);
+      break;
+
+    case GIMP_CURVE_FREE:
+      view->last_x = x;
+      view->last_y = y;
+
+      gimp_curve_set_curve (curve, x, 1.0 - y);
+      break;
+    }
+
+  if (! gtk_widget_has_focus (widget))
+    gtk_widget_grab_focus (widget);
+
+  return TRUE;
+}
+
+static gboolean
+gimp_curve_view_button_release (GtkWidget      *widget,
+                                GdkEventButton *bevent)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (widget);
+
+  if (bevent->button != 1)
+    return TRUE;
+
+  g_clear_object (&view->orig_curve);
+
+  view->offset_x = 0.0;
+  view->offset_y = 0.0;
+
+  view->grabbed = FALSE;
+
+  set_cursor (view, GDK_FLEUR);
+
+  return TRUE;
+}
+
+static gboolean
+gimp_curve_view_motion_notify (GtkWidget      *widget,
+                               GdkEventMotion *mevent)
+{
+  GimpCurveView  *view       = GIMP_CURVE_VIEW (widget);
+  GimpCurve      *curve      = view->curve;
+  GtkAllocation   allocation;
+  GdkCursorType   new_cursor = GDK_X_CURSOR;
+  gint            border;
+  gint            width, height;
+  gdouble         x;
+  gdouble         y;
+  gdouble         point_x;
+  gdouble         point_y;
+  gint            point;
+
+  if (! curve)
+    return TRUE;
+
+  gtk_widget_get_allocation (widget, &allocation);
+
+  border = GIMP_HISTOGRAM_VIEW (view)->border_width;
+  width  = allocation.width  - 2 * border;
+  height = allocation.height - 2 * border;
+
+  x = (gdouble) (mevent->x - border) / (gdouble) width;
+  y = (gdouble) (mevent->y - border) / (gdouble) height;
+
+  x += view->offset_x;
+  y += view->offset_y;
+
+  x = CLAMP (x, 0.0, 1.0);
+  y = CLAMP (y, 0.0, 1.0);
+
+  switch (gimp_curve_get_curve_type (curve))
+    {
+    case GIMP_CURVE_SMOOTH:
+      if (! view->grabbed) /*  If no point is grabbed...  */
+        {
+          point = gimp_curve_get_closest_point (curve, x, 1.0 - y,
+                                                POINT_MAX_DISTANCE /
+                                                MAX (width, height));
+
+          if (point >= 0)
+            {
+              gimp_curve_get_point (curve, point, &point_x, &point_y);
+
+              new_cursor = GDK_FLEUR;
+
+              x = point_x;
+              y = 1.0 - point_y;
+            }
+          else
+            {
+              new_cursor = GDK_TCROSS;
+
+              if (mevent->state & gimp_get_constrain_behavior_mask ())
+                y = 1.0 - gimp_curve_map_value (view->curve, x);
+            }
+        }
+      else /*  Else, drag the grabbed point  */
+        {
+          new_cursor = GDK_TCROSS;
+
+          if (mevent->state & gimp_get_constrain_behavior_mask ())
+            y = 1.0 - gimp_curve_map_value (view->orig_curve, x);
+
+          gimp_data_freeze (GIMP_DATA (curve));
+
+          if (x > view->leftmost && x < view->rightmost)
+            {
+              if (view->selected < 0)
+                {
+                  gimp_curve_view_set_selected (
+                    view,
+                    gimp_curve_add_point (curve, x, 1.0 - y));
+
+                  gimp_curve_set_point_type (curve,
+                                             view->selected, view->point_type);
+                }
+              else
+                {
+                  gimp_curve_set_point (curve, view->selected, x, 1.0 - y);
+                }
+            }
+          else
+            {
+              if (view->selected >= 0)
+                {
+                  gimp_curve_delete_point (curve, view->selected);
+
+                  gimp_curve_view_set_selected (view, -1);
+                }
+            }
+
+          gimp_data_thaw (GIMP_DATA (curve));
+        }
+      break;
+
+    case GIMP_CURVE_FREE:
+      if (view->grabbed)
+        {
+          gint    n_samples = gimp_curve_get_n_samples (curve);
+          gdouble x1, x2;
+          gdouble y1, y2;
+
+          if (view->last_x > x)
+            {
+              x1 = x;
+              x2 = view->last_x;
+              y1 = y;
+              y2 = view->last_y;
+            }
+          else
+            {
+              x1 = view->last_x;
+              x2 = x;
+              y1 = view->last_y;
+              y2 = y;
+            }
+
+          if (x2 != x1)
+            {
+              gint from = ROUND (x1 * (gdouble) (n_samples - 1));
+              gint to   = ROUND (x2 * (gdouble) (n_samples - 1));
+              gint i;
+
+              gimp_data_freeze (GIMP_DATA (curve));
+
+              for (i = from; i <= to; i++)
+                {
+                  gdouble xpos = (gdouble) i / (gdouble) (n_samples - 1);
+                  gdouble ypos = (y1 + ((y2 - y1) * (xpos - x1)) / (x2 - x1));
+
+                  xpos = CLAMP (xpos, 0.0, 1.0);
+                  ypos = CLAMP (ypos, 0.0, 1.0);
+
+                  gimp_curve_set_curve (curve, xpos, 1.0 - ypos);
+                }
+
+              gimp_data_thaw (GIMP_DATA (curve));
+            }
+          else
+            {
+              gimp_curve_set_curve (curve, x, 1.0 - y);
+            }
+
+          view->last_x = x;
+          view->last_y = y;
+        }
+
+      if (mevent->state & GDK_BUTTON1_MASK)
+        new_cursor = GDK_TCROSS;
+      else
+        new_cursor = GDK_PENCIL;
+
+      break;
+    }
+
+  set_cursor (view, new_cursor);
+
+  gimp_curve_view_set_cursor (view, x, y);
+
+  return TRUE;
+}
+
+static gboolean
+gimp_curve_view_leave_notify (GtkWidget        *widget,
+                              GdkEventCrossing *cevent)
+{
+  GimpCurveView *view = GIMP_CURVE_VIEW (widget);
+
+  gimp_curve_view_unset_cursor (view);
+
+  return TRUE;
+}
+
+static gboolean
+gimp_curve_view_key_press (GtkWidget   *widget,
+                           GdkEventKey *kevent)
+{
+  GimpCurveView *view    = GIMP_CURVE_VIEW (widget);
+  GimpCurve     *curve   = view->curve;
+  gboolean       handled = FALSE;
+
+  if (! view->grabbed                                        &&
+      curve                                                  &&
+      gimp_curve_get_curve_type (curve) == GIMP_CURVE_SMOOTH &&
+      view->selected                    >= 0)
+    {
+      gint    i = view->selected;
+      gdouble x, y;
+
+      gimp_curve_get_point (curve, i, NULL, &y);
+
+      switch (kevent->keyval)
+        {
+        case GDK_KEY_Left:
+          for (i = i - 1; i >= 0 && ! handled; i--)
+            {
+              gimp_curve_get_point (curve, i, &x, NULL);
+
+              if (x >= 0.0)
+                {
+                  gimp_curve_view_set_selected (view, i);
+
+                  handled = TRUE;
+                }
+            }
+          break;
+
+        case GDK_KEY_Right:
+          for (i = i + 1; i < curve->n_points && ! handled; i++)
+            {
+              gimp_curve_get_point (curve, i, &x, NULL);
+
+              if (x >= 0.0)
+                {
+                  gimp_curve_view_set_selected (view, i);
+
+                  handled = TRUE;
+                }
+            }
+          break;
+
+        case GDK_KEY_Up:
+          if (y < 1.0)
+            {
+              y = y + (kevent->state & GDK_SHIFT_MASK ?
+                       (16.0 / 255.0) : (1.0 / 255.0));
+
+              gimp_curve_move_point (curve, i, CLAMP (y, 0.0, 1.0));
+
+              handled = TRUE;
+            }
+          break;
+
+        case GDK_KEY_Down:
+          if (y > 0)
+            {
+              y = y - (kevent->state & GDK_SHIFT_MASK ?
+                       (16.0 / 255.0) : (1.0 / 255.0));
+
+              gimp_curve_move_point (curve, i, CLAMP (y, 0.0, 1.0));
+
+              handled = TRUE;
+            }
+          break;
+
+        case GDK_KEY_Delete:
+          gimp_curve_delete_point (curve, i);
+          break;
+
+        default:
+          break;
+        }
+    }
+
+  if (handled)
+    {
+      set_cursor (view, GDK_TCROSS);
+
+      return TRUE;
+    }
+
+  return GTK_WIDGET_CLASS (parent_class)->key_press_event (widget, kevent);
+}
+
+static void
+gimp_curve_view_cut_clipboard (GimpCurveView *view)
+{
+  g_printerr ("%s\n", G_STRFUNC);
+
+  if (! view->curve || ! view->gimp)
+    {
+      gtk_widget_error_bell (GTK_WIDGET (view));
+      return;
+    }
+
+  gimp_curve_view_copy_clipboard (view);
+
+  gimp_curve_reset (view->curve, FALSE);
+}
+
+static void
+gimp_curve_view_copy_clipboard (GimpCurveView *view)
+{
+  GimpCurve *copy;
+
+  g_printerr ("%s\n", G_STRFUNC);
+
+  if (! view->curve || ! view->gimp)
+    {
+      gtk_widget_error_bell (GTK_WIDGET (view));
+      return;
+    }
+
+  copy = GIMP_CURVE (gimp_data_duplicate (GIMP_DATA (view->curve)));
+  gimp_clipboard_set_curve (view->gimp, copy);
+  g_object_unref (copy);
+}
+
+static void
+gimp_curve_view_paste_clipboard (GimpCurveView *view)
+{
+  GimpCurve *copy;
+
+  g_printerr ("%s\n", G_STRFUNC);
+
+  if (! view->curve || ! view->gimp)
+    {
+      gtk_widget_error_bell (GTK_WIDGET (view));
+      return;
+    }
+
+  copy = gimp_clipboard_get_curve (view->gimp);
+
+  if (copy)
+    {
+      gimp_config_copy (GIMP_CONFIG (copy),
+                        GIMP_CONFIG (view->curve), 0);
+      g_object_unref (copy);
+    }
+}
+
+static void
+gimp_curve_view_curve_dirty (GimpCurve     *curve,
+                             GimpCurveView *view)
+{
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+static void
+gimp_curve_view_curve_notify_n_points (GimpCurve     *curve,
+                                       GParamSpec    *pspec,
+                                       GimpCurveView *view)
+{
+  gimp_curve_view_set_selected (view, -1);
+}
+
+
+/*  public functions  */
+
+GtkWidget *
+gimp_curve_view_new (void)
+{
+  return g_object_new (GIMP_TYPE_CURVE_VIEW, NULL);
+}
+
+void
+gimp_curve_view_set_curve (GimpCurveView *view,
+                           GimpCurve     *curve,
+                           const GimpRGB *color)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+  g_return_if_fail (curve == NULL || GIMP_IS_CURVE (curve));
+
+  if (view->curve == curve)
+    return;
+
+  if (view->curve)
+    {
+      g_signal_handlers_disconnect_by_func (view->curve,
+                                            gimp_curve_view_curve_dirty,
+                                            view);
+      g_signal_handlers_disconnect_by_func (view->curve,
+                                            gimp_curve_view_curve_notify_n_points,
+                                            view);
+      g_object_unref (view->curve);
+    }
+
+  view->curve = curve;
+
+  if (view->curve)
+    {
+      g_object_ref (view->curve);
+      g_signal_connect (view->curve, "dirty",
+                        G_CALLBACK (gimp_curve_view_curve_dirty),
+                        view);
+      g_signal_connect (view->curve, "notify::n-points",
+                        G_CALLBACK (gimp_curve_view_curve_notify_n_points),
+                        view);
+    }
+
+  if (view->curve_color)
+    g_free (view->curve_color);
+
+  if (color)
+    view->curve_color = g_memdup (color, sizeof (GimpRGB));
+  else
+    view->curve_color = NULL;
+
+  gimp_curve_view_set_selected (view, -1);
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+GimpCurve *
+gimp_curve_view_get_curve (GimpCurveView *view)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE_VIEW (view), NULL);
+
+  return view->curve;
+}
+
+void
+gimp_curve_view_add_background (GimpCurveView *view,
+                                GimpCurve     *curve,
+                                const GimpRGB *color)
+{
+  GList   *list;
+  BGCurve *bg;
+
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+
+  for (list = view->bg_curves; list; list = g_list_next (list))
+    {
+      bg = list->data;
+
+      g_return_if_fail (curve != bg->curve);
+    }
+
+  bg = g_slice_new0 (BGCurve);
+
+  bg->curve = g_object_ref (curve);
+
+  if (color)
+    {
+      bg->color     = *color;
+      bg->color_set = TRUE;
+    }
+
+  g_signal_connect (bg->curve, "dirty",
+                    G_CALLBACK (gimp_curve_view_curve_dirty),
+                    view);
+
+  view->bg_curves = g_list_append (view->bg_curves, bg);
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+void
+gimp_curve_view_remove_background (GimpCurveView *view,
+                                   GimpCurve     *curve)
+{
+  GList *list;
+
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+
+  for (list = view->bg_curves; list; list = g_list_next (list))
+    {
+      BGCurve *bg = list->data;
+
+      if (bg->curve == curve)
+        {
+          g_signal_handlers_disconnect_by_func (bg->curve,
+                                                gimp_curve_view_curve_dirty,
+                                                view);
+          g_object_unref (bg->curve);
+
+          view->bg_curves = g_list_remove (view->bg_curves, bg);
+
+          g_slice_free (BGCurve, bg);
+
+          gtk_widget_queue_draw (GTK_WIDGET (view));
+
+          break;
+        }
+    }
+
+  if (! list)
+    g_return_if_reached ();
+}
+
+void
+gimp_curve_view_remove_all_backgrounds (GimpCurveView *view)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  while (view->bg_curves)
+    {
+      BGCurve *bg = view->bg_curves->data;
+
+      g_signal_handlers_disconnect_by_func (bg->curve,
+                                            gimp_curve_view_curve_dirty,
+                                            view);
+      g_object_unref (bg->curve);
+
+      view->bg_curves = g_list_remove (view->bg_curves, bg);
+
+      g_slice_free (BGCurve, bg);
+    }
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+void
+gimp_curve_view_set_selected (GimpCurveView *view,
+                              gint           selected)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  if (selected != view->selected)
+    {
+      view->selected = selected;
+
+      g_signal_emit (view, curve_view_signals[SELECTION_CHANGED], 0);
+
+      gtk_widget_queue_draw (GTK_WIDGET (view));
+    }
+}
+
+gint
+gimp_curve_view_get_selected (GimpCurveView *view)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE_VIEW (view), -1);
+
+  if (view->curve && view->selected < gimp_curve_get_n_points (view->curve))
+    return view->selected;
+  else
+    return -1;
+}
+
+void
+gimp_curve_view_set_range_x (GimpCurveView *view,
+                             gdouble        min,
+                             gdouble        max)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  view->range_x_min = min;
+  view->range_x_max = max;
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+void
+gimp_curve_view_set_range_y (GimpCurveView *view,
+                             gdouble        min,
+                             gdouble        max)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  view->range_y_min = min;
+  view->range_y_max = max;
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+void
+gimp_curve_view_set_xpos (GimpCurveView *view,
+                          gdouble        x)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  view->xpos = x;
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+void
+gimp_curve_view_set_x_axis_label (GimpCurveView *view,
+                                  const gchar   *label)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  if (view->x_axis_label)
+    g_free (view->x_axis_label);
+
+  view->x_axis_label = g_strdup (label);
+
+  g_object_notify (G_OBJECT (view), "x-axis-label");
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+void
+gimp_curve_view_set_y_axis_label (GimpCurveView *view,
+                                  const gchar   *label)
+{
+  g_return_if_fail (GIMP_IS_CURVE_VIEW (view));
+
+  if (view->y_axis_label)
+    g_free (view->y_axis_label);
+
+  view->y_axis_label = g_strdup (label);
+
+  g_object_notify (G_OBJECT (view), "y-axis-label");
+
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+
+/*  private functions  */
+
+static void
+gimp_curve_view_set_cursor (GimpCurveView *view,
+                            gdouble        x,
+                            gdouble        y)
+{
+  view->cursor_x = x;
+  view->cursor_y = y;
+
+  /* TODO: only invalidate the cursor label area */
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}
+
+static void
+gimp_curve_view_unset_cursor (GimpCurveView *view)
+{
+  view->cursor_x = -1.0;
+  view->cursor_y = -1.0;
+
+  /* TODO: only invalidate the cursor label area */
+  gtk_widget_queue_draw (GTK_WIDGET (view));
+}