Adding upstream version 2.10.22.upstream/2.10.22upstream

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

1 files changed, 1289 insertions, 0 deletions

diff --git a/app/core/gimpcurve.c b/app/core/gimpcurve.c
new file mode 100644
index 0000000..bde20b2
--- /dev/null
+++ b/app/core/gimpcurve.c
@@ -0,0 +1,1289 @@
+/* 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 <stdlib.h>
+#include <string.h> /* memcmp */
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <gegl.h>
+
+#include "libgimpbase/gimpbase.h"
+#include "libgimpmath/gimpmath.h"
+#include "libgimpconfig/gimpconfig.h"
+
+#include "core-types.h"
+
+#include "gimpcurve.h"
+#include "gimpcurve-load.h"
+#include "gimpcurve-save.h"
+#include "gimpparamspecs.h"
+
+#include "gimp-intl.h"
+
+
+#define EPSILON 1e-6
+
+
+enum
+{
+  PROP_0,
+  PROP_CURVE_TYPE,
+  PROP_N_POINTS,
+  PROP_POINTS,
+  PROP_POINT_TYPES,
+  PROP_N_SAMPLES,
+  PROP_SAMPLES
+};
+
+
+/*  local function prototypes  */
+
+static void          gimp_curve_config_iface_init (GimpConfigInterface *iface);
+
+static void          gimp_curve_finalize          (GObject          *object);
+static void          gimp_curve_set_property      (GObject          *object,
+                                                   guint             property_id,
+                                                   const GValue     *value,
+                                                   GParamSpec       *pspec);
+static void          gimp_curve_get_property      (GObject          *object,
+                                                   guint             property_id,
+                                                   GValue           *value,
+                                                   GParamSpec       *pspec);
+
+static gint64        gimp_curve_get_memsize       (GimpObject       *object,
+                                                   gint64           *gui_size);
+
+static void          gimp_curve_get_preview_size  (GimpViewable     *viewable,
+                                                   gint              size,
+                                                   gboolean          popup,
+                                                   gboolean          dot_for_dot,
+                                                   gint             *width,
+                                                   gint             *height);
+static gboolean      gimp_curve_get_popup_size    (GimpViewable     *viewable,
+                                                   gint              width,
+                                                   gint              height,
+                                                   gboolean          dot_for_dot,
+                                                   gint             *popup_width,
+                                                   gint             *popup_height);
+static GimpTempBuf * gimp_curve_get_new_preview   (GimpViewable     *viewable,
+                                                   GimpContext      *context,
+                                                   gint              width,
+                                                   gint              height);
+static gchar       * gimp_curve_get_description   (GimpViewable     *viewable,
+                                                   gchar           **tooltip);
+
+static void          gimp_curve_dirty             (GimpData         *data);
+static const gchar * gimp_curve_get_extension     (GimpData         *data);
+static void          gimp_curve_data_copy         (GimpData         *data,
+                                                   GimpData         *src_data);
+
+static gboolean      gimp_curve_serialize         (GimpConfig       *config,
+                                                   GimpConfigWriter *writer,
+                                                   gpointer          data);
+static gboolean      gimp_curve_deserialize       (GimpConfig       *config,
+                                                   GScanner         *scanner,
+                                                   gint              nest_level,
+                                                   gpointer          data);
+static gboolean      gimp_curve_equal             (GimpConfig       *a,
+                                                   GimpConfig       *b);
+static void          _gimp_curve_reset            (GimpConfig       *config);
+static gboolean      gimp_curve_config_copy       (GimpConfig       *src,
+                                                   GimpConfig       *dest,
+                                                   GParamFlags       flags);
+
+static void          gimp_curve_calculate         (GimpCurve        *curve);
+static void          gimp_curve_plot              (GimpCurve        *curve,
+                                                   gint              p1,
+                                                   gint              p2,
+                                                   gint              p3,
+                                                   gint              p4);
+
+
+G_DEFINE_TYPE_WITH_CODE (GimpCurve, gimp_curve, GIMP_TYPE_DATA,
+                         G_IMPLEMENT_INTERFACE (GIMP_TYPE_CONFIG,
+                                                gimp_curve_config_iface_init))
+
+#define parent_class gimp_curve_parent_class
+
+
+static void
+gimp_curve_class_init (GimpCurveClass *klass)
+{
+  GObjectClass      *object_class      = G_OBJECT_CLASS (klass);
+  GimpObjectClass   *gimp_object_class = GIMP_OBJECT_CLASS (klass);
+  GimpViewableClass *viewable_class    = GIMP_VIEWABLE_CLASS (klass);
+  GimpDataClass     *data_class        = GIMP_DATA_CLASS (klass);
+  GParamSpec        *array_spec;
+
+  object_class->finalize            = gimp_curve_finalize;
+  object_class->set_property        = gimp_curve_set_property;
+  object_class->get_property        = gimp_curve_get_property;
+
+  gimp_object_class->get_memsize    = gimp_curve_get_memsize;
+
+  viewable_class->default_icon_name = "FIXME icon name";
+  viewable_class->get_preview_size  = gimp_curve_get_preview_size;
+  viewable_class->get_popup_size    = gimp_curve_get_popup_size;
+  viewable_class->get_new_preview   = gimp_curve_get_new_preview;
+  viewable_class->get_description   = gimp_curve_get_description;
+
+  data_class->dirty                 = gimp_curve_dirty;
+  data_class->save                  = gimp_curve_save;
+  data_class->get_extension         = gimp_curve_get_extension;
+  data_class->copy                  = gimp_curve_data_copy;
+
+  GIMP_CONFIG_PROP_ENUM (object_class, PROP_CURVE_TYPE,
+                         "curve-type",
+                         "Curve Type",
+                         "The curve type",
+                         GIMP_TYPE_CURVE_TYPE,
+                         GIMP_CURVE_SMOOTH, 0);
+
+  GIMP_CONFIG_PROP_INT (object_class, PROP_N_POINTS,
+                        "n-points",
+                        "Number of Points",
+                        "The number of points",
+                        0, G_MAXINT, 0,
+                        /* for backward compatibility */
+                        GIMP_CONFIG_PARAM_IGNORE);
+
+  array_spec = g_param_spec_double ("point", NULL, NULL,
+                                    -1.0, 1.0, 0.0, GIMP_PARAM_READWRITE);
+  g_object_class_install_property (object_class, PROP_POINTS,
+                                   gimp_param_spec_value_array ("points",
+                                                                NULL, NULL,
+                                                                array_spec,
+                                                                GIMP_PARAM_STATIC_STRINGS |
+                                                                GIMP_CONFIG_PARAM_FLAGS));
+
+  array_spec = g_param_spec_enum ("point-type", NULL, NULL,
+                                  GIMP_TYPE_CURVE_POINT_TYPE,
+                                  GIMP_CURVE_POINT_SMOOTH,
+                                  GIMP_PARAM_READWRITE);
+  g_object_class_install_property (object_class, PROP_POINT_TYPES,
+                                   gimp_param_spec_value_array ("point-types",
+                                                                NULL, NULL,
+                                                                array_spec,
+                                                                GIMP_PARAM_STATIC_STRINGS |
+                                                                GIMP_CONFIG_PARAM_FLAGS));
+
+  GIMP_CONFIG_PROP_INT  (object_class, PROP_N_SAMPLES,
+                         "n-samples",
+                         "Number of Samples",
+                         "The number of samples",
+                         256, 256, 256, 0);
+
+  array_spec = g_param_spec_double ("sample", NULL, NULL,
+                                    0.0, 1.0, 0.0, GIMP_PARAM_READWRITE);
+  g_object_class_install_property (object_class, PROP_SAMPLES,
+                                   gimp_param_spec_value_array ("samples",
+                                                                NULL, NULL,
+                                                                array_spec,
+                                                                GIMP_PARAM_STATIC_STRINGS |
+                                                                GIMP_CONFIG_PARAM_FLAGS));
+}
+
+static void
+gimp_curve_config_iface_init (GimpConfigInterface *iface)
+{
+  iface->serialize   = gimp_curve_serialize;
+  iface->deserialize = gimp_curve_deserialize;
+  iface->equal       = gimp_curve_equal;
+  iface->reset       = _gimp_curve_reset;
+  iface->copy        = gimp_curve_config_copy;
+}
+
+static void
+gimp_curve_init (GimpCurve *curve)
+{
+  curve->n_points  = 0;
+  curve->points    = NULL;
+  curve->n_samples = 0;
+  curve->samples   = NULL;
+  curve->identity  = FALSE;
+}
+
+static void
+gimp_curve_finalize (GObject *object)
+{
+  GimpCurve *curve = GIMP_CURVE (object);
+
+  g_clear_pointer (&curve->points,  g_free);
+  curve->n_points = 0;
+
+  g_clear_pointer (&curve->samples, g_free);
+  curve->n_samples = 0;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gimp_curve_set_property (GObject      *object,
+                         guint         property_id,
+                         const GValue *value,
+                         GParamSpec   *pspec)
+{
+  GimpCurve *curve = GIMP_CURVE (object);
+
+  switch (property_id)
+    {
+    case PROP_CURVE_TYPE:
+      gimp_curve_set_curve_type (curve, g_value_get_enum (value));
+      break;
+
+    case PROP_N_POINTS:
+      /* ignored */
+      break;
+
+    case PROP_POINTS:
+      {
+        GimpValueArray *array = g_value_get_boxed (value);
+        GimpCurvePoint *points;
+        gint            length;
+        gint            n_points;
+        gint            i;
+
+        if (! array)
+          {
+            gimp_curve_clear_points (curve);
+
+            break;
+          }
+
+        length = gimp_value_array_length (array) / 2;
+
+        n_points = 0;
+        points   = g_new0 (GimpCurvePoint, length);
+
+        for (i = 0; i < length; i++)
+          {
+            GValue *x = gimp_value_array_index (array, i * 2);
+            GValue *y = gimp_value_array_index (array, i * 2 + 1);
+
+            /* for backward compatibility */
+            if (g_value_get_double (x) < 0.0)
+              continue;
+
+            points[n_points].x = CLAMP (g_value_get_double (x), 0.0, 1.0);
+            points[n_points].y = CLAMP (g_value_get_double (y), 0.0, 1.0);
+
+            if (n_points > 0)
+              {
+                points[n_points].x = MAX (points[n_points].x,
+                                          points[n_points - 1].x);
+              }
+
+            if (n_points < curve->n_points)
+              points[n_points].type = curve->points[n_points].type;
+            else
+              points[n_points].type = GIMP_CURVE_POINT_SMOOTH;
+
+            n_points++;
+          }
+
+        g_free (curve->points);
+
+        curve->n_points = n_points;
+        curve->points   = points;
+
+        g_object_notify (object, "n-points");
+        g_object_notify (object, "point-types");
+      }
+      break;
+
+    case PROP_POINT_TYPES:
+      {
+        GimpValueArray *array = g_value_get_boxed (value);
+        GimpCurvePoint *points;
+        gint            length;
+        gdouble         x     = 0.0;
+        gdouble         y     = 0.0;
+        gint            i;
+
+        if (! array)
+          {
+            gimp_curve_clear_points (curve);
+
+            break;
+          }
+
+        length = gimp_value_array_length (array);
+
+        points = g_new0 (GimpCurvePoint, length);
+
+        for (i = 0; i < length; i++)
+          {
+            GValue *type = gimp_value_array_index (array, i);
+
+            points[i].type = g_value_get_enum (type);
+
+            if (i < curve->n_points)
+              {
+                x = curve->points[i].x;
+                y = curve->points[i].y;
+              }
+
+            points[i].x = x;
+            points[i].y = y;
+          }
+
+        g_free (curve->points);
+
+        curve->n_points = length;
+        curve->points   = points;
+
+        g_object_notify (object, "n-points");
+        g_object_notify (object, "points");
+      }
+      break;
+
+    case PROP_N_SAMPLES:
+      gimp_curve_set_n_samples (curve, g_value_get_int (value));
+      break;
+
+    case PROP_SAMPLES:
+      {
+        GimpValueArray *array = g_value_get_boxed (value);
+        gint            length;
+        gint            i;
+
+        if (! array)
+          break;
+
+        length = gimp_value_array_length (array);
+
+        for (i = 0; i < curve->n_samples && i < length; i++)
+          {
+            GValue *v = gimp_value_array_index (array, i);
+
+            curve->samples[i] = CLAMP (g_value_get_double (v), 0.0, 1.0);
+          }
+      }
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_curve_get_property (GObject    *object,
+                         guint       property_id,
+                         GValue     *value,
+                         GParamSpec *pspec)
+{
+  GimpCurve *curve = GIMP_CURVE (object);
+
+  switch (property_id)
+    {
+    case PROP_CURVE_TYPE:
+      g_value_set_enum (value, curve->curve_type);
+      break;
+
+    case PROP_N_POINTS:
+      g_value_set_int (value, curve->n_points);
+      break;
+
+    case PROP_POINTS:
+      {
+        GimpValueArray *array = gimp_value_array_new (curve->n_points * 2);
+        GValue          v     = G_VALUE_INIT;
+        gint            i;
+
+        g_value_init (&v, G_TYPE_DOUBLE);
+
+        for (i = 0; i < curve->n_points; i++)
+          {
+            g_value_set_double (&v, curve->points[i].x);
+            gimp_value_array_append (array, &v);
+
+            g_value_set_double (&v, curve->points[i].y);
+            gimp_value_array_append (array, &v);
+          }
+
+        g_value_unset (&v);
+
+        g_value_take_boxed (value, array);
+      }
+      break;
+
+    case PROP_POINT_TYPES:
+      {
+        GimpValueArray *array = gimp_value_array_new (curve->n_points);
+        GValue          v     = G_VALUE_INIT;
+        gint            i;
+
+        g_value_init (&v, GIMP_TYPE_CURVE_POINT_TYPE);
+
+        for (i = 0; i < curve->n_points; i++)
+          {
+            g_value_set_enum (&v, curve->points[i].type);
+            gimp_value_array_append (array, &v);
+          }
+
+        g_value_unset (&v);
+
+        g_value_take_boxed (value, array);
+      }
+      break;
+
+    case PROP_N_SAMPLES:
+      g_value_set_int (value, curve->n_samples);
+      break;
+
+    case PROP_SAMPLES:
+      {
+        GimpValueArray *array = gimp_value_array_new (curve->n_samples);
+        GValue          v     = G_VALUE_INIT;
+        gint            i;
+
+        g_value_init (&v, G_TYPE_DOUBLE);
+
+        for (i = 0; i < curve->n_samples; i++)
+          {
+            g_value_set_double (&v, curve->samples[i]);
+            gimp_value_array_append (array, &v);
+          }
+
+        g_value_unset (&v);
+
+        g_value_take_boxed (value, array);
+      }
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static gint64
+gimp_curve_get_memsize (GimpObject *object,
+                        gint64     *gui_size)
+{
+  GimpCurve *curve   = GIMP_CURVE (object);
+  gint64     memsize = 0;
+
+  memsize += curve->n_points  * sizeof (GimpCurvePoint);
+  memsize += curve->n_samples * sizeof (gdouble);
+
+  return memsize + GIMP_OBJECT_CLASS (parent_class)->get_memsize (object,
+                                                                  gui_size);
+}
+
+static void
+gimp_curve_get_preview_size (GimpViewable *viewable,
+                             gint          size,
+                             gboolean      popup,
+                             gboolean      dot_for_dot,
+                             gint         *width,
+                             gint         *height)
+{
+  *width  = size;
+  *height = size;
+}
+
+static gboolean
+gimp_curve_get_popup_size (GimpViewable *viewable,
+                           gint          width,
+                           gint          height,
+                           gboolean      dot_for_dot,
+                           gint         *popup_width,
+                           gint         *popup_height)
+{
+  *popup_width  = width  * 2;
+  *popup_height = height * 2;
+
+  return TRUE;
+}
+
+static GimpTempBuf *
+gimp_curve_get_new_preview (GimpViewable *viewable,
+                            GimpContext  *context,
+                            gint          width,
+                            gint          height)
+{
+  return NULL;
+}
+
+static gchar *
+gimp_curve_get_description (GimpViewable  *viewable,
+                            gchar        **tooltip)
+{
+  GimpCurve *curve = GIMP_CURVE (viewable);
+
+  return g_strdup_printf ("%s", gimp_object_get_name (curve));
+}
+
+static void
+gimp_curve_dirty (GimpData *data)
+{
+  GimpCurve *curve = GIMP_CURVE (data);
+
+  curve->identity = FALSE;
+
+  gimp_curve_calculate (curve);
+
+  GIMP_DATA_CLASS (parent_class)->dirty (data);
+}
+
+static const gchar *
+gimp_curve_get_extension (GimpData *data)
+{
+  return GIMP_CURVE_FILE_EXTENSION;
+}
+
+static void
+gimp_curve_data_copy (GimpData *data,
+                      GimpData *src_data)
+{
+  gimp_data_freeze (data);
+
+  gimp_config_copy (GIMP_CONFIG (src_data),
+                    GIMP_CONFIG (data), 0);
+
+  gimp_data_thaw (data);
+}
+
+static gboolean
+gimp_curve_serialize (GimpConfig       *config,
+                      GimpConfigWriter *writer,
+                      gpointer          data)
+{
+  return gimp_config_serialize_properties (config, writer);
+}
+
+static gboolean
+gimp_curve_deserialize (GimpConfig *config,
+                        GScanner   *scanner,
+                        gint        nest_level,
+                        gpointer    data)
+{
+  gboolean success;
+
+  success = gimp_config_deserialize_properties (config, scanner, nest_level);
+
+  GIMP_CURVE (config)->identity = FALSE;
+
+  return success;
+}
+
+static gboolean
+gimp_curve_equal (GimpConfig *a,
+                  GimpConfig *b)
+{
+  GimpCurve *a_curve = GIMP_CURVE (a);
+  GimpCurve *b_curve = GIMP_CURVE (b);
+
+  if (a_curve->curve_type != b_curve->curve_type)
+    return FALSE;
+
+  if (a_curve->n_points != b_curve->n_points ||
+      memcmp (a_curve->points, b_curve->points,
+              sizeof (GimpCurvePoint) * a_curve->n_points))
+    {
+      return FALSE;
+    }
+
+  if (a_curve->n_samples != b_curve->n_samples ||
+      memcmp (a_curve->samples, b_curve->samples,
+              sizeof (gdouble) * a_curve->n_samples))
+    {
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+static void
+_gimp_curve_reset (GimpConfig *config)
+{
+  gimp_curve_reset (GIMP_CURVE (config), TRUE);
+}
+
+static gboolean
+gimp_curve_config_copy (GimpConfig  *src,
+                        GimpConfig  *dest,
+                        GParamFlags  flags)
+{
+  GimpCurve *src_curve  = GIMP_CURVE (src);
+  GimpCurve *dest_curve = GIMP_CURVE (dest);
+
+  /* make sure the curve type is copied *before* the points, so that we don't
+   * overwrite the copied points when changing the type
+   */
+  dest_curve->curve_type = src_curve->curve_type;
+
+  gimp_config_sync (G_OBJECT (src), G_OBJECT (dest), flags);
+
+  dest_curve->identity = src_curve->identity;
+
+  gimp_data_dirty (GIMP_DATA (dest));
+
+  return TRUE;
+}
+
+
+/*  public functions  */
+
+GimpData *
+gimp_curve_new (const gchar *name)
+{
+  g_return_val_if_fail (name != NULL, NULL);
+  g_return_val_if_fail (*name != '\0', NULL);
+
+  return g_object_new (GIMP_TYPE_CURVE,
+                       "name", name,
+                       NULL);
+}
+
+GimpData *
+gimp_curve_get_standard (void)
+{
+  static GimpData *standard_curve = NULL;
+
+  if (! standard_curve)
+    {
+      standard_curve = gimp_curve_new ("Standard");
+
+      gimp_data_clean (standard_curve);
+      gimp_data_make_internal (standard_curve,
+                               "gimp-curve-standard");
+
+      g_object_ref (standard_curve);
+    }
+
+  return standard_curve;
+}
+
+void
+gimp_curve_reset (GimpCurve *curve,
+                  gboolean   reset_type)
+{
+  gint i;
+
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+
+  g_object_freeze_notify (G_OBJECT (curve));
+
+  for (i = 0; i < curve->n_samples; i++)
+    curve->samples[i] = (gdouble) i / (gdouble) (curve->n_samples - 1);
+
+  g_object_notify (G_OBJECT (curve), "samples");
+
+  g_free (curve->points);
+
+  curve->n_points = 2;
+  curve->points   = g_new0 (GimpCurvePoint, 2);
+
+  curve->points[0].x    = 0.0;
+  curve->points[0].y    = 0.0;
+  curve->points[0].type = GIMP_CURVE_POINT_SMOOTH;
+
+  curve->points[1].x    = 1.0;
+  curve->points[1].y    = 1.0;
+  curve->points[1].type = GIMP_CURVE_POINT_SMOOTH;
+
+  g_object_notify (G_OBJECT (curve), "n-points");
+  g_object_notify (G_OBJECT (curve), "points");
+  g_object_notify (G_OBJECT (curve), "point-types");
+
+  if (reset_type)
+    {
+      curve->curve_type = GIMP_CURVE_SMOOTH;
+      g_object_notify (G_OBJECT (curve), "curve-type");
+    }
+
+  curve->identity = TRUE;
+
+  g_object_thaw_notify (G_OBJECT (curve));
+
+  gimp_data_dirty (GIMP_DATA (curve));
+}
+
+void
+gimp_curve_set_curve_type (GimpCurve     *curve,
+                           GimpCurveType  curve_type)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+
+  if (curve->curve_type != curve_type)
+    {
+      gimp_data_freeze (GIMP_DATA (curve));
+
+      g_object_freeze_notify (G_OBJECT (curve));
+
+      curve->curve_type = curve_type;
+
+      if (curve_type == GIMP_CURVE_SMOOTH)
+        {
+          gint i;
+
+          g_free (curve->points);
+
+          /*  pick some points from the curve and make them control
+           *  points
+           */
+          curve->n_points = 9;
+          curve->points   = g_new0 (GimpCurvePoint, 9);
+
+          for (i = 0; i < curve->n_points; i++)
+            {
+              gint sample = i * (curve->n_samples - 1) / (curve->n_points - 1);
+
+              curve->points[i].x    = (gdouble) sample /
+                                      (gdouble) (curve->n_samples - 1);
+              curve->points[i].y    = curve->samples[sample];
+              curve->points[i].type = GIMP_CURVE_POINT_SMOOTH;
+            }
+
+          g_object_notify (G_OBJECT (curve), "n-points");
+          g_object_notify (G_OBJECT (curve), "points");
+          g_object_notify (G_OBJECT (curve), "point-types");
+        }
+      else
+        {
+          gimp_curve_clear_points (curve);
+        }
+
+      g_object_notify (G_OBJECT (curve), "curve-type");
+
+      g_object_thaw_notify (G_OBJECT (curve));
+
+      gimp_data_thaw (GIMP_DATA (curve));
+    }
+}
+
+GimpCurveType
+gimp_curve_get_curve_type (GimpCurve *curve)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), GIMP_CURVE_SMOOTH);
+
+  return curve->curve_type;
+}
+
+gint
+gimp_curve_get_n_points (GimpCurve *curve)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), 0);
+
+  return curve->n_points;
+}
+
+void
+gimp_curve_set_n_samples (GimpCurve *curve,
+                          gint       n_samples)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (n_samples >= 256);
+  g_return_if_fail (n_samples <= 4096);
+
+  if (n_samples != curve->n_samples)
+    {
+      gint i;
+
+      g_object_freeze_notify (G_OBJECT (curve));
+
+      curve->n_samples = n_samples;
+      g_object_notify (G_OBJECT (curve), "n-samples");
+
+      curve->samples = g_renew (gdouble, curve->samples, curve->n_samples);
+
+      for (i = 0; i < curve->n_samples; i++)
+        curve->samples[i] = (gdouble) i / (gdouble) (curve->n_samples - 1);
+
+      g_object_notify (G_OBJECT (curve), "samples");
+
+      if (curve->curve_type == GIMP_CURVE_FREE)
+        curve->identity = TRUE;
+
+      g_object_thaw_notify (G_OBJECT (curve));
+    }
+}
+
+gint
+gimp_curve_get_n_samples (GimpCurve *curve)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), 0);
+
+  return curve->n_samples;
+}
+
+gint
+gimp_curve_get_point_at (GimpCurve *curve,
+                         gdouble    x)
+{
+  gint    closest_point = -1;
+  gdouble distance      = EPSILON;
+  gint    i;
+
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), -1);
+
+  for (i = 0; i < curve->n_points; i++)
+    {
+      gdouble point_distance;
+
+      point_distance = fabs (x - curve->points[i].x);
+
+      if (point_distance <= distance)
+        {
+          closest_point = i;
+          distance      = point_distance;
+        }
+    }
+
+  return closest_point;
+}
+
+gint
+gimp_curve_get_closest_point (GimpCurve *curve,
+                              gdouble    x,
+                              gdouble    y,
+                              gdouble    max_distance)
+{
+  gint    closest_point = -1;
+  gdouble distance2     = G_MAXDOUBLE;
+  gint    i;
+
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), -1);
+
+  if (max_distance >= 0.0)
+    distance2 = SQR (max_distance);
+
+  for (i = curve->n_points - 1; i >= 0; i--)
+    {
+      gdouble point_distance2;
+
+      point_distance2 = SQR (x - curve->points[i].x) +
+                        SQR (y - curve->points[i].y);
+
+      if (point_distance2 <= distance2)
+        {
+          closest_point = i;
+          distance2     = point_distance2;
+        }
+    }
+
+  return closest_point;
+}
+
+gint
+gimp_curve_add_point (GimpCurve *curve,
+                      gdouble    x,
+                      gdouble    y)
+{
+  GimpCurvePoint *points;
+  gint            point;
+
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), -1);
+
+  if (curve->curve_type == GIMP_CURVE_FREE)
+    return -1;
+
+  x = CLAMP (x, 0.0, 1.0);
+  y = CLAMP (y, 0.0, 1.0);
+
+  for (point = 0; point < curve->n_points; point++)
+    {
+      if (curve->points[point].x > x)
+        break;
+    }
+
+  points = g_new0 (GimpCurvePoint, curve->n_points + 1);
+
+  memcpy (points,         curve->points,
+          point * sizeof (GimpCurvePoint));
+  memcpy (points + point + 1, curve->points + point,
+          (curve->n_points - point) * sizeof (GimpCurvePoint));
+
+  points[point].x    = x;
+  points[point].y    = y;
+  points[point].type = GIMP_CURVE_POINT_SMOOTH;
+
+  g_free (curve->points);
+
+  curve->n_points++;
+  curve->points = points;
+
+  g_object_notify (G_OBJECT (curve), "n-points");
+  g_object_notify (G_OBJECT (curve), "points");
+  g_object_notify (G_OBJECT (curve), "point-types");
+
+  gimp_data_dirty (GIMP_DATA (curve));
+
+  return point;
+}
+
+void
+gimp_curve_delete_point (GimpCurve *curve,
+                         gint       point)
+{
+  GimpCurvePoint *points;
+
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (point >= 0 && point < curve->n_points);
+
+  points = g_new0 (GimpCurvePoint, curve->n_points - 1);
+
+  memcpy (points,         curve->points,
+          point * sizeof (GimpCurvePoint));
+  memcpy (points + point, curve->points + point + 1,
+          (curve->n_points - point - 1) * sizeof (GimpCurvePoint));
+
+  g_free (curve->points);
+
+  curve->n_points--;
+  curve->points = points;
+
+  g_object_notify (G_OBJECT (curve), "n-points");
+  g_object_notify (G_OBJECT (curve), "points");
+  g_object_notify (G_OBJECT (curve), "point-types");
+
+  gimp_data_dirty (GIMP_DATA (curve));
+}
+
+void
+gimp_curve_set_point (GimpCurve *curve,
+                      gint       point,
+                      gdouble    x,
+                      gdouble    y)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (point >= 0 && point < curve->n_points);
+
+  curve->points[point].x = CLAMP (x, 0.0, 1.0);
+  curve->points[point].y = CLAMP (y, 0.0, 1.0);
+
+  if (point > 0)
+    curve->points[point].x = MAX (x, curve->points[point - 1].x);
+
+  if (point < curve->n_points - 1)
+    curve->points[point].x = MIN (x, curve->points[point + 1].x);
+
+  g_object_notify (G_OBJECT (curve), "points");
+
+  gimp_data_dirty (GIMP_DATA (curve));
+}
+
+void
+gimp_curve_move_point (GimpCurve *curve,
+                       gint       point,
+                       gdouble    y)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (point >= 0 && point < curve->n_points);
+
+  curve->points[point].y = CLAMP (y, 0.0, 1.0);
+
+  g_object_notify (G_OBJECT (curve), "points");
+
+  gimp_data_dirty (GIMP_DATA (curve));
+}
+
+void
+gimp_curve_get_point (GimpCurve *curve,
+                      gint       point,
+                      gdouble   *x,
+                      gdouble   *y)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (point >= 0 && point < curve->n_points);
+
+  if (x) *x = curve->points[point].x;
+  if (y) *y = curve->points[point].y;
+}
+
+void
+gimp_curve_set_point_type (GimpCurve          *curve,
+                           gint                point,
+                           GimpCurvePointType  type)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (point >= 0 && point < curve->n_points);
+
+  curve->points[point].type = type;
+
+  g_object_notify (G_OBJECT (curve), "point-types");
+
+  gimp_data_dirty (GIMP_DATA (curve));
+}
+
+GimpCurvePointType
+gimp_curve_get_point_type (GimpCurve *curve,
+                           gint       point)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), GIMP_CURVE_POINT_SMOOTH);
+  g_return_val_if_fail (point >= 0 && point < curve->n_points, GIMP_CURVE_POINT_SMOOTH);
+
+  return curve->points[point].type;
+}
+
+void
+gimp_curve_clear_points (GimpCurve *curve)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+
+  if (curve->points)
+    {
+      g_clear_pointer (&curve->points, g_free);
+      curve->n_points = 0;
+
+      g_object_notify (G_OBJECT (curve), "n-points");
+      g_object_notify (G_OBJECT (curve), "points");
+      g_object_notify (G_OBJECT (curve), "point-types");
+
+      gimp_data_dirty (GIMP_DATA (curve));
+    }
+}
+
+void
+gimp_curve_set_curve (GimpCurve *curve,
+                      gdouble    x,
+                      gdouble    y)
+{
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  g_return_if_fail (x >= 0 && x <= 1.0);
+  g_return_if_fail (y >= 0 && y <= 1.0);
+
+  if (curve->curve_type == GIMP_CURVE_SMOOTH)
+    return;
+
+  curve->samples[ROUND (x * (gdouble) (curve->n_samples - 1))] = y;
+
+  g_object_notify (G_OBJECT (curve), "samples");
+
+  gimp_data_dirty (GIMP_DATA (curve));
+}
+
+/**
+ * gimp_curve_is_identity:
+ * @curve: a #GimpCurve object
+ *
+ * If this function returns %TRUE, then the curve maps each value to
+ * itself. If it returns %FALSE, then this assumption can not be made.
+ *
+ * Return value: %TRUE if the curve is an identity mapping, %FALSE otherwise.
+ **/
+gboolean
+gimp_curve_is_identity (GimpCurve *curve)
+{
+  g_return_val_if_fail (GIMP_IS_CURVE (curve), FALSE);
+
+  return curve->identity;
+}
+
+void
+gimp_curve_get_uchar (GimpCurve *curve,
+                      gint       n_samples,
+                      guchar    *samples)
+{
+  gint i;
+
+  g_return_if_fail (GIMP_IS_CURVE (curve));
+  /* FIXME: support n_samples != curve->n_samples */
+  g_return_if_fail (n_samples == curve->n_samples);
+  g_return_if_fail (samples != NULL);
+
+  for (i = 0; i < curve->n_samples; i++)
+    samples[i] = curve->samples[i] * 255.999;
+}
+
+
+/*  private functions  */
+
+static void
+gimp_curve_calculate (GimpCurve *curve)
+{
+  gint i;
+  gint p1, p2, p3, p4;
+
+  if (gimp_data_is_frozen (GIMP_DATA (curve)))
+    return;
+
+  switch (curve->curve_type)
+    {
+    case GIMP_CURVE_SMOOTH:
+      /*  Initialize boundary curve points */
+      if (curve->n_points > 0)
+        {
+          GimpCurvePoint point;
+          gint           boundary;
+
+          point    = curve->points[0];
+          boundary = ROUND (point.x * (gdouble) (curve->n_samples - 1));
+
+          for (i = 0; i < boundary; i++)
+            curve->samples[i] = point.y;
+
+          point    = curve->points[curve->n_points - 1];
+          boundary = ROUND (point.x * (gdouble) (curve->n_samples - 1));
+
+          for (i = boundary; i < curve->n_samples; i++)
+            curve->samples[i] = point.y;
+        }
+
+      for (i = 0; i < curve->n_points - 1; i++)
+        {
+          p1 = MAX (i - 1, 0);
+          p2 = i;
+          p3 = i + 1;
+          p4 = MIN (i + 2, curve->n_points - 1);
+
+          if (curve->points[p2].type == GIMP_CURVE_POINT_CORNER)
+            p1 = p2;
+
+          if (curve->points[p3].type == GIMP_CURVE_POINT_CORNER)
+            p4 = p3;
+
+          gimp_curve_plot (curve, p1, p2, p3, p4);
+        }
+
+      /* ensure that the control points are used exactly */
+      for (i = 0; i < curve->n_points; i++)
+        {
+          gdouble x = curve->points[i].x;
+          gdouble y = curve->points[i].y;
+
+          curve->samples[ROUND (x * (gdouble) (curve->n_samples - 1))] = y;
+        }
+
+      g_object_notify (G_OBJECT (curve), "samples");
+      break;
+
+    case GIMP_CURVE_FREE:
+      break;
+    }
+}
+
+/*
+ * This function calculates the curve values between the control points
+ * p2 and p3, taking the potentially existing neighbors p1 and p4 into
+ * account.
+ *
+ * This function uses a cubic bezier curve for the individual segments and
+ * calculates the necessary intermediate control points depending on the
+ * neighbor curve control points.
+ */
+static void
+gimp_curve_plot (GimpCurve *curve,
+                 gint       p1,
+                 gint       p2,
+                 gint       p3,
+                 gint       p4)
+{
+  gint    i;
+  gdouble x0, x3;
+  gdouble y0, y1, y2, y3;
+  gdouble dx, dy;
+  gdouble slope;
+
+  /* the outer control points for the bezier curve. */
+  x0 = curve->points[p2].x;
+  y0 = curve->points[p2].y;
+  x3 = curve->points[p3].x;
+  y3 = curve->points[p3].y;
+
+  /*
+   * the x values of the inner control points are fixed at
+   * x1 = 2/3*x0 + 1/3*x3   and  x2 = 1/3*x0 + 2/3*x3
+   * this ensures that the x values increase linearly with the
+   * parameter t and enables us to skip the calculation of the x
+   * values altogether - just calculate y(t) evenly spaced.
+   */
+
+  dx = x3 - x0;
+  dy = y3 - y0;
+
+  if (dx <= EPSILON)
+    {
+      gint index;
+
+      index = ROUND (x0 * (gdouble) (curve->n_samples - 1));
+
+      curve->samples[index] = y3;
+
+      return;
+    }
+
+  if (p1 == p2 && p3 == p4)
+    {
+      /* No information about the neighbors,
+       * calculate y1 and y2 to get a straight line
+       */
+      y1 = y0 + dy / 3.0;
+      y2 = y0 + dy * 2.0 / 3.0;
+    }
+  else if (p1 == p2 && p3 != p4)
+    {
+      /* only the right neighbor is available. Make the tangent at the
+       * right endpoint parallel to the line between the left endpoint
+       * and the right neighbor. Then point the tangent at the left towards
+       * the control handle of the right tangent, to ensure that the curve
+       * does not have an inflection point.
+       */
+      slope = (curve->points[p4].y - y0) / (curve->points[p4].x - x0);
+
+      y2 = y3 - slope * dx / 3.0;
+      y1 = y0 + (y2 - y0) / 2.0;
+    }
+  else if (p1 != p2 && p3 == p4)
+    {
+      /* see previous case */
+      slope = (y3 - curve->points[p1].y) / (x3 - curve->points[p1].x);
+
+      y1 = y0 + slope * dx / 3.0;
+      y2 = y3 + (y1 - y3) / 2.0;
+    }
+  else /* (p1 != p2 && p3 != p4) */
+    {
+      /* Both neighbors are available. Make the tangents at the endpoints
+       * parallel to the line between the opposite endpoint and the adjacent
+       * neighbor.
+       */
+      slope = (y3 - curve->points[p1].y) / (x3 - curve->points[p1].x);
+
+      y1 = y0 + slope * dx / 3.0;
+
+      slope = (curve->points[p4].y - y0) / (curve->points[p4].x - x0);
+
+      y2 = y3 - slope * dx / 3.0;
+    }
+
+  /*
+   * finally calculate the y(t) values for the given bezier values. We can
+   * use homogeneously distributed values for t, since x(t) increases linearly.
+   */
+  for (i = 0; i <= ROUND (dx * (gdouble) (curve->n_samples - 1)); i++)
+    {
+      gdouble y, t;
+      gint    index;
+
+      t = i / dx / (gdouble) (curve->n_samples - 1);
+      y =     y0 * (1-t) * (1-t) * (1-t) +
+          3 * y1 * (1-t) * (1-t) * t     +
+          3 * y2 * (1-t) * t     * t     +
+              y3 * t     * t     * t;
+
+      index = i + ROUND (x0 * (gdouble) (curve->n_samples - 1));
+
+      if (index < curve->n_samples)
+        curve->samples[index] = CLAMP (y, 0.0, 1.0);
+    }
+}