From b45098c71ca5dab7345e2b2f704ae6452a7b52cb Mon Sep 17 00:00:00 2001
From: Cyril Hrubis <metan@ucw.cz>
Date: Tue, 5 Jun 2012 15:18:09 +0200
Subject: [PATCH] filters: Add noise filter.

---
 demos/grinder/grinder.c       | 25 ++++++++++++++++++++++++-
 include/filters/GP_Point.h    |  6 ++++++
 libs/filters/GP_Noise.gen.c.t | 34 ++++++++++++++++++++++++++++++++++
 libs/filters/Makefile         |  2 +-
 4 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 libs/filters/GP_Noise.gen.c.t

diff --git a/demos/grinder/grinder.c b/demos/grinder/grinder.c
index abdf5464..1bc73600 100644
--- a/demos/grinder/grinder.c
+++ b/demos/grinder/grinder.c
@@ -16,7 +16,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  * Boston, MA  02110-1301  USA                                               *
  *                                                                           *
- * Copyright (C) 2009-2011 Cyril Hrubis <metan@ucw.cz>                       *
+ * Copyright (C) 2009-2012 Cyril Hrubis <metan@ucw.cz>                       *
  *                                                                           *
  *****************************************************************************/
 
@@ -354,6 +354,28 @@ static GP_RetCode contrast(GP_Context **c, const char *params)
 	return GP_ESUCCESS;
 }
 
+/* noise */
+static struct param noise_params[] = {
+	{"ratio", PARAM_FLOAT, "noise", NULL, NULL},
+	{NULL,  0,            NULL,    NULL, NULL}
+};
+
+static GP_RetCode noise(GP_Context **c, const char *params)
+{
+	float rat;
+
+	if (param_parse(params, noise_params, "noise", param_err, &rat))
+		return GP_EINVAL;
+
+	GP_FILTER_PARAMS((*c)->pixel_type, filter_params);
+	
+	GP_FilterParamSetFloatAll(filter_params, rat);
+
+	GP_FilterNoise(*c, *c, filter_params, progress_callback);
+
+	return GP_ESUCCESS;
+}
+
 /* invert */
 
 static struct param invert_params[] = {
@@ -675,6 +697,7 @@ static struct filter filter_table[] = {
 	{"contrast",   "alter image contrast", contrast_params, contrast},
 	{"invert",     "inverts image", invert_params, invert},
 	{"add_noise",  "adds noise", add_noise_params, add_noise},
+	{"noise",      "adds noise",  noise_params, noise},
 	{"blur",       "gaussian blur", blur_params, blur},
 	{"dither",     "dithers bitmap", dither_params, dither},
 	{"arithmetic", "arithmetic operation", arithmetic_params, arithmetic},
diff --git a/include/filters/GP_Point.h b/include/filters/GP_Point.h
index 1ab37566..31e9747d 100644
--- a/include/filters/GP_Point.h
+++ b/include/filters/GP_Point.h
@@ -72,6 +72,12 @@ GP_Context *GP_FilterInvert(const GP_Context *src, GP_Context *dst,
                             GP_ProgressCallback *callback);
 
 /*
+ * Noise filter.
+ */
+GP_Context *GP_FilterNoise(const GP_Context *src, GP_Context *dst,
+                           GP_FilterParam ratio[], GP_ProgressCallback *callback);
+
+/*
  * Generic slow point filter.
  *
  * The filter_callback[] is expected to be filled with pointers
diff --git a/libs/filters/GP_Noise.gen.c.t b/libs/filters/GP_Noise.gen.c.t
new file mode 100644
index 00000000..7afca65b
--- /dev/null
+++ b/libs/filters/GP_Noise.gen.c.t
@@ -0,0 +1,34 @@
+%% extends "filter.point.c.t"
+
+{% block descr %}Noise filter -- Adds noise to an image.{% endblock %}
+
+%% block body
+
+{{ filter_point_include() }}
+
+%% macro filter_op(chann_name, chann_size)
+{{ chann_name }} = {{ chann_name }} + (random() % ({{ chann_name }}_max * 2)) - {{ chann_name }}_max;
+{{ filter_clamp_val(chann_name, chann_size) }}
+%% endmacro
+
+/*
+ * Generated noise filters.
+ */
+%% call(pt) filter_point_per_channel('Noise', 'GP_FilterParam ratio[]', filter_op)
+{{ filter_params(pt, 'ratio', 'float ', '_rat', 'f') }}
+%% for chann in pt.chanslist
+	int {{ chann[0] }}_max = {{ chann[0] }}_rat * {{ 2 ** chann[2] - 1}} + 0.5;
+%% endfor
+%% endcall
+
+/*
+ * Generated noise filters for pixels with one channel.
+ */
+%% call(ps) filter_point_per_bpp('Noise', 'GP_FilterParam ratio[]', filter_op)
+{{ filter_param(ps, 'ratio', 'float ', '_rat', 'f') }}
+	int pix_max = pix_rat * {{ 2 ** ps.size - 1}} + 0.5;
+%% endcall
+
+{{ filter_functions('Noise', 'GP_FilterParam ratio[]', 'ratio') }}
+
+%% endblock body
diff --git a/libs/filters/Makefile b/libs/filters/Makefile
index 4bed64af..49993aa7 100644
--- a/libs/filters/Makefile
+++ b/libs/filters/Makefile
@@ -3,7 +3,7 @@ TOPDIR=../..
 STATS_FILTERS=GP_Histogram.gen.c
 
 POINT_FILTERS=GP_Contrast.gen.c GP_Brightness.gen.c GP_Invert.gen.c\
-              GP_Point.gen.c
+              GP_Point.gen.c GP_Noise.gen.c
 
 ARITHMETIC_FILTERS=GP_Difference.gen.c GP_Addition.gen.c GP_Min.gen.c\
                    GP_Max.gen.c GP_Multiply.gen.c
-- 
2.11.4.GIT