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-rw-r--r--app/operations/layer-modes/gimpoperationbehind.c236
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diff --git a/app/operations/layer-modes/gimpoperationbehind.c b/app/operations/layer-modes/gimpoperationbehind.c
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+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpoperationbehind.c
+ * Copyright (C) 2008 Michael Natterer <mitch@gimp.org>
+ * 2012 Ville Sokk <ville.sokk@gmail.com>
+ *
+ * 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 <gegl-plugin.h>
+
+#include "../operations-types.h"
+
+#include "gimpoperationbehind.h"
+
+
+
+static gboolean gimp_operation_behind_process (GeglOperation *op,
+ void *in,
+ void *layer,
+ void *mask,
+ void *out,
+ glong samples,
+ const GeglRectangle *roi,
+ gint level);
+
+
+G_DEFINE_TYPE (GimpOperationBehind, gimp_operation_behind,
+ GIMP_TYPE_OPERATION_LAYER_MODE)
+
+
+static void
+gimp_operation_behind_class_init (GimpOperationBehindClass *klass)
+{
+ GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
+ GimpOperationLayerModeClass *layer_mode_class = GIMP_OPERATION_LAYER_MODE_CLASS (klass);
+
+ gegl_operation_class_set_keys (operation_class,
+ "name", "gimp:behind",
+ "description", "GIMP behind mode operation",
+ NULL);
+
+ layer_mode_class->process = gimp_operation_behind_process;
+}
+
+static void
+gimp_operation_behind_init (GimpOperationBehind *self)
+{
+}
+
+static gboolean
+gimp_operation_behind_process (GeglOperation *op,
+ void *in_p,
+ void *layer_p,
+ void *mask_p,
+ void *out_p,
+ glong samples,
+ const GeglRectangle *roi,
+ gint level)
+{
+ GimpOperationLayerMode *layer_mode = (gpointer) op;
+ gfloat *in = in_p;
+ gfloat *out = out_p;
+ gfloat *layer = layer_p;
+ gfloat *mask = mask_p;
+ gfloat opacity = layer_mode->opacity;
+ const gboolean has_mask = mask != NULL;
+
+ switch (layer_mode->composite_mode)
+ {
+ case GIMP_LAYER_COMPOSITE_UNION:
+ case GIMP_LAYER_COMPOSITE_AUTO:
+ while (samples--)
+ {
+ gfloat src1_alpha = in[ALPHA];
+ gfloat src2_alpha = layer[ALPHA] * opacity;
+ gfloat new_alpha;
+ gint b;
+
+ if (has_mask)
+ src2_alpha *= *mask;
+
+ new_alpha = src2_alpha + (1.0 - src2_alpha) * src1_alpha;
+
+ if (new_alpha)
+ {
+ gfloat ratio = in[ALPHA] / new_alpha;
+ gfloat compl_ratio = 1.0f - ratio;
+
+ for (b = RED; b < ALPHA; b++)
+ {
+ out[b] = in[b] * ratio + layer[b] * compl_ratio;
+ }
+ }
+ else
+ {
+ for (b = RED; b < ALPHA; b++)
+ {
+ out[b] = layer[b];
+ }
+ }
+
+ out[ALPHA] = new_alpha;
+
+ in += 4;
+ layer += 4;
+ out += 4;
+
+ if (has_mask)
+ mask++;
+ }
+ break;
+
+ case GIMP_LAYER_COMPOSITE_CLIP_TO_BACKDROP:
+ while (samples--)
+ {
+ gfloat src1_alpha = in[ALPHA];
+ gfloat new_alpha;
+ gint b;
+
+ new_alpha = src1_alpha;
+
+ if (new_alpha)
+ {
+ for (b = RED; b < ALPHA; b++)
+ out[b] = in[b];
+ }
+ else
+ {
+ for (b = RED; b < ALPHA; b++)
+ out[b] = layer[b];
+ }
+
+ out[ALPHA] = new_alpha;
+
+ in += 4;
+ layer += 4;
+ out += 4;
+ }
+ break;
+
+ case GIMP_LAYER_COMPOSITE_CLIP_TO_LAYER:
+ while (samples--)
+ {
+ gfloat src1_alpha = in[ALPHA];
+ gfloat src2_alpha = layer[ALPHA] * opacity;
+ gfloat new_alpha;
+ gint b;
+
+ if (has_mask)
+ src2_alpha *= *mask;
+
+ new_alpha = src2_alpha;
+
+ if (new_alpha)
+ {
+ for (b = RED; b < ALPHA; b++)
+ {
+ out[b] = layer[b] + (in[b] - layer[b]) * src1_alpha;
+ }
+ }
+ else
+ {
+ for (b = RED; b < ALPHA; b++)
+ {
+ out[b] = layer[b];
+ }
+ }
+
+ out[ALPHA] = new_alpha;
+
+ in += 4;
+ layer += 4;
+ out += 4;
+
+ if (has_mask)
+ mask++;
+ }
+ break;
+
+ case GIMP_LAYER_COMPOSITE_INTERSECTION:
+ while (samples--)
+ {
+ gfloat src1_alpha = in[ALPHA];
+ gfloat src2_alpha = layer[ALPHA] * opacity;
+ gfloat new_alpha;
+ gint b;
+
+ if (has_mask)
+ src2_alpha *= *mask;
+
+ new_alpha = src1_alpha * src2_alpha;
+
+ if (new_alpha)
+ {
+ for (b = RED; b < ALPHA; b++)
+ {
+ out[b] = in[b];
+ }
+ }
+ else
+ {
+ for (b = RED; b < ALPHA; b++)
+ {
+ out[b] = layer[b];
+ }
+ }
+
+ out[ALPHA] = new_alpha;
+
+ in += 4;
+ layer += 4;
+ out += 4;
+
+ if (has_mask)
+ mask++;
+ }
+ break;
+ }
+
+ return TRUE;
+}