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-rw-r--r--app/operations/gimpoperationthresholdalpha.c178
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diff --git a/app/operations/gimpoperationthresholdalpha.c b/app/operations/gimpoperationthresholdalpha.c
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+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpoperationthresholdalpha.c
+ * Copyright (C) 2012 Michael Natterer <mitch@gimp.org>
+ *
+ * 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/>.
+ *
+ * Ported from the threshold-alpha plug-in
+ * Copyright (C) 1997 Shuji Narazaki <narazaki@InetQ.or.jp>
+ */
+
+#include "config.h"
+
+#include <gegl.h>
+
+#include "operations-types.h"
+
+#include "gimpoperationthresholdalpha.h"
+
+#include "gimp-intl.h"
+
+
+enum
+{
+ PROP_0,
+ PROP_VALUE
+};
+
+
+static void gimp_operation_threshold_alpha_get_property (GObject *object,
+ guint property_id,
+ GValue *value,
+ GParamSpec *pspec);
+static void gimp_operation_threshold_alpha_set_property (GObject *object,
+ guint property_id,
+ const GValue *value,
+ GParamSpec *pspec);
+
+static void gimp_operation_threshold_alpha_prepare (GeglOperation *operation);
+static gboolean gimp_operation_threshold_alpha_process (GeglOperation *operation,
+ void *in_buf,
+ void *out_buf,
+ glong samples,
+ const GeglRectangle *roi,
+ gint level);
+
+
+G_DEFINE_TYPE (GimpOperationThresholdAlpha, gimp_operation_threshold_alpha,
+ GEGL_TYPE_OPERATION_POINT_FILTER)
+
+#define parent_class gimp_operation_threshold_alpha_parent_class
+
+
+static void
+gimp_operation_threshold_alpha_class_init (GimpOperationThresholdAlphaClass *klass)
+{
+ GObjectClass *object_class = G_OBJECT_CLASS (klass);
+ GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
+ GeglOperationPointFilterClass *point_class = GEGL_OPERATION_POINT_FILTER_CLASS (klass);
+
+ object_class->set_property = gimp_operation_threshold_alpha_set_property;
+ object_class->get_property = gimp_operation_threshold_alpha_get_property;
+
+ gegl_operation_class_set_keys (operation_class,
+ "name", "gimp:threshold-alpha",
+ "categories", "color",
+ "description",
+ _("Make transparency all-or-nothing, by "
+ "thresholding the alpha channel to a value"),
+ NULL);
+
+ operation_class->prepare = gimp_operation_threshold_alpha_prepare;
+
+ point_class->process = gimp_operation_threshold_alpha_process;
+
+ g_object_class_install_property (object_class, PROP_VALUE,
+ g_param_spec_double ("value",
+ _("Value"),
+ _("The alpha value"),
+ 0.0, 1.0, 0.5,
+ G_PARAM_READWRITE |
+ G_PARAM_CONSTRUCT));
+}
+
+static void
+gimp_operation_threshold_alpha_init (GimpOperationThresholdAlpha *self)
+{
+}
+
+static void
+gimp_operation_threshold_alpha_get_property (GObject *object,
+ guint property_id,
+ GValue *value,
+ GParamSpec *pspec)
+{
+ GimpOperationThresholdAlpha *self = GIMP_OPERATION_THRESHOLD_ALPHA (object);
+
+ switch (property_id)
+ {
+ case PROP_VALUE:
+ g_value_set_double (value, self->value);
+ break;
+
+ default:
+ G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+ break;
+ }
+}
+
+static void
+gimp_operation_threshold_alpha_set_property (GObject *object,
+ guint property_id,
+ const GValue *value,
+ GParamSpec *pspec)
+{
+ GimpOperationThresholdAlpha *self = GIMP_OPERATION_THRESHOLD_ALPHA (object);
+
+ switch (property_id)
+ {
+ case PROP_VALUE:
+ self->value = g_value_get_double (value);
+ break;
+
+ default:
+ G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+ break;
+ }
+}
+
+static void
+gimp_operation_threshold_alpha_prepare (GeglOperation *operation)
+{
+ const Babl *space = gegl_operation_get_source_space (operation, "input");
+ gegl_operation_set_format (operation, "input", babl_format_with_space ("RGBA float", space));
+ gegl_operation_set_format (operation, "output", babl_format_with_space ("RGBA float", space));
+}
+
+static gboolean
+gimp_operation_threshold_alpha_process (GeglOperation *operation,
+ void *in_buf,
+ void *out_buf,
+ glong samples,
+ const GeglRectangle *roi,
+ gint level)
+{
+ GimpOperationThresholdAlpha *self = GIMP_OPERATION_THRESHOLD_ALPHA (operation);
+ gfloat *src = in_buf;
+ gfloat *dest = out_buf;
+
+ while (samples--)
+ {
+ dest[RED] = src[RED];
+ dest[GREEN] = src[GREEN];
+ dest[BLUE] = src[BLUE];
+
+ if (src[ALPHA] > self->value)
+ dest[ALPHA] = 1.0;
+ else
+ dest[ALPHA] = 0.0;
+
+ src += 4;
+ dest += 4;
+ }
+
+ return TRUE;
+}