1 files changed, 77 insertions, 0 deletions
diff --git a/app/core/gimpdrawable-levels.c b/app/core/gimpdrawable-levels.c
new file mode 100644
index 0000000..301326b
--- /dev/null
+++ b/app/core/gimpdrawable-levels.c
@@ -0,0 +1,77 @@
+/* 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 <gdk-pixbuf/gdk-pixbuf.h>
+#include <gegl.h>
+
+#include "core-types.h"
+
+#include "operations/gimplevelsconfig.h"
+
+#include "gimpdrawable.h"
+#include "gimpdrawable-histogram.h"
+#include "gimpdrawable-levels.h"
+#include "gimpdrawable-operation.h"
+#include "gimphistogram.h"
+#include "gimpprogress.h"
+
+#include "gimp-intl.h"
+
+
+/*  public functions  */
+
+void
+gimp_drawable_levels_stretch (GimpDrawable *drawable,
+                              GimpProgress *progress)
+{
+  GimpLevelsConfig *config;
+  GimpHistogram    *histogram;
+  GeglNode         *levels;
+
+  g_return_if_fail (GIMP_IS_DRAWABLE (drawable));
+  g_return_if_fail (gimp_item_is_attached (GIMP_ITEM (drawable)));
+  g_return_if_fail (progress == NULL || GIMP_IS_PROGRESS (progress));
+
+  if (! gimp_item_mask_intersect (GIMP_ITEM (drawable), NULL, NULL, NULL, NULL))
+    return;
+
+  config = g_object_new (GIMP_TYPE_LEVELS_CONFIG, NULL);
+
+  histogram = gimp_histogram_new (FALSE);
+  gimp_drawable_calculate_histogram (drawable, histogram, FALSE);
+
+  gimp_levels_config_stretch (config, histogram,
+                              gimp_drawable_is_rgb (drawable));
+
+  g_object_unref (histogram);
+
+  levels = g_object_new (GEGL_TYPE_NODE,
+                         "operation", "gimp:levels",
+                         NULL);
+
+  gegl_node_set (levels,
+                 "config", config,
+                 NULL);
+
+  gimp_drawable_apply_operation (drawable, progress, _("Levels"),
+                                 levels);
+
+  g_object_unref (levels);
+  g_object_unref (config);
+}