[gegl] workshop: add lowbit-dither, experimental dithering for floating point
- From: Øyvind Kolås <ok src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gegl] workshop: add lowbit-dither, experimental dithering for floating point
- Date: Tue, 20 Dec 2016 22:10:53 +0000 (UTC)
commit 9babb32603c1adbc8103d847af3d605e2d197ed8
Author: Øyvind Kolås <pippin gimp org>
Date: Tue Dec 20 23:04:41 2016 +0100
workshop: add lowbit-dither, experimental dithering for floating point
operations/workshop/Makefile.am | 1 +
operations/workshop/lowbit-dither.c | 105 +++++++++++++++++++++++++++++++++++
2 files changed, 106 insertions(+), 0 deletions(-)
---
diff --git a/operations/workshop/Makefile.am b/operations/workshop/Makefile.am
index 93e7686..13f3949 100644
--- a/operations/workshop/Makefile.am
+++ b/operations/workshop/Makefile.am
@@ -25,6 +25,7 @@ op_LTLIBRARIES = \
rawbayer-load.la \
unpremul.la \
vhsfix.la \
+ lowbit-dither.la \
waterpixels.la \
watershed-transform.la \
wavelet-blur.la
diff --git a/operations/workshop/lowbit-dither.c b/operations/workshop/lowbit-dither.c
new file mode 100644
index 0000000..ac9cb7a
--- /dev/null
+++ b/operations/workshop/lowbit-dither.c
@@ -0,0 +1,105 @@
+/* This file is an image processing operation for GEGL
+ *
+ * GEGL is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * GEGL 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GEGL; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2016 Øyvind Kolås <pippin gimp org>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_PROPERTIES
+
+#else
+
+#define GEGL_OP_POINT_FILTER
+#define GEGL_OP_C_SOURCE lowbit-dither.c
+#define GEGL_OP_NAME lowbit_dither
+
+#include "gegl-op.h"
+
+#include <math.h>
+
+static void
+prepare (GeglOperation *operation)
+{
+ gegl_operation_set_format (operation, "input", babl_format ("R'G'B'A float"));
+ gegl_operation_set_format (operation, "output", babl_format ("R'G'B'A float"));
+}
+
+static gboolean
+process (GeglOperation *operation,
+ void *in_buf,
+ void *out_buf,
+ glong n_pixels,
+ const GeglRectangle *roi,
+ gint level)
+{
+ //GeglProperties *o = GEGL_PROPERTIES (operation);
+ gfloat *in_pixel = in_buf;
+ gfloat *out_pixel = out_buf;
+ gint x, y;
+
+ x = roi->x;
+ y = roi->y;
+
+ while (n_pixels--)
+ {
+ int ch;
+ for (ch = 0; ch < 4; ch++)
+ {
+ if (in_pixel [ch] > 0.0000001f && in_pixel [ch] < 1.0000000f)
+ out_pixel [ch] = in_pixel [ch] + ((((((x+ch * 67) + y * 236) * 119) & 255)/255.0f)-0.5f )/255.0f;
+ /* this computes an 8bit http://pippin.gimp.org/a_dither/ mask */
+ else
+ out_pixel [ch] = in_pixel [ch];
+ }
+ out_pixel += 4;
+ in_pixel += 4;
+
+ /* update x and y coordinates */
+ if (++x>=roi->x + roi->width)
+ {
+ x=roi->x;
+ y++;
+ }
+ }
+
+ return TRUE;
+}
+
+static void
+gegl_op_class_init (GeglOpClass *klass)
+{
+ GeglOperationClass *operation_class;
+ GeglOperationPointFilterClass *point_filter_class;
+
+ operation_class = GEGL_OPERATION_CLASS (klass);
+ point_filter_class = GEGL_OPERATION_POINT_FILTER_CLASS (klass);
+
+ operation_class->prepare = prepare;
+ operation_class->no_cache = TRUE;
+ operation_class->opencl_support = TRUE;
+
+ point_filter_class->process = process;
+
+ gegl_operation_class_set_keys (operation_class,
+ "name", "gegl:lowbit-dither",
+ "title", _("Lowbit dither"),
+ "position-dependent", "true",
+ "description", _("dithers adequately to mask out 8bit sRGB TRC quantization for high bitdepth formats"),
+ NULL);
+}
+
+#endif
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