Add Posterize filter

2 files changed, 161 insertions, 0 deletions

diff --git a/src/filter/posterize/CMakeLists.txt b/src/filter/posterize/CMakeLists.txt
new file mode 100644
index 0000000..0e6c1b0
--- a/dev/null
+++ b/src/filter/posterize/CMakeLists.txt
@@ -0,0 +1,12 @@
+set (SOURCES posterize.c)
+set (TARGET posterize)
+
+if (MSVC)
+ set_source_files_properties (posterize.c PROPERTIES LANGUAGE CXX)
+ set (SOURCES ${SOURCES} ${FREI0R_DEF})
+endif (MSVC)
+
+add_library (${TARGET} MODULE ${SOURCES})
+set_target_properties (${TARGET} PROPERTIES PREFIX "")
+
+install (TARGETS ${TARGET} LIBRARY DESTINATION ${LIBDIR})
diff --git a/src/filter/posterize/posterize.c b/src/filter/posterize/posterize.c
new file mode 100644
index 0000000..eb28b17
--- a/dev/null
+++ b/src/filter/posterize/posterize.c
@@ -0,0 +1,149 @@
+/*
+ * This file is a port of com.jhlabs.image.PosterizeFilter.java
+ * Copyright 2006 Jerry Huxtable
+ *
+ * posterize.c
+ * Copyright 2012 Janne Liljeblad 
+ *
+ * This file is a Frei0r plugin.
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include "frei0r.h"
+#include "frei0r_math.h"
+
+typedef struct posterize_instance
+{
+ unsigned int width;
+ unsigned int height;
+ double levels;
+} posterize_instance_t;
+
+int f0r_init()
+{
+ return 1;
+}
+
+void f0r_deinit()
+{ /* no initialization required */ }
+
+void f0r_get_plugin_info(f0r_plugin_info_t* posterize_info)
+{
+ posterize_info->name = "posterize";
+ posterize_info->author = "Janne Liljeblad";
+ posterize_info->plugin_type = F0R_PLUGIN_TYPE_FILTER;
+ posterize_info->color_model = F0R_COLOR_MODEL_RGBA8888;
+ posterize_info->frei0r_version = FREI0R_MAJOR_VERSION;
+ posterize_info->major_version = 0; 
+ posterize_info->minor_version = 1; 
+ posterize_info->num_params = 1; 
+ posterize_info->explanation = "Posterizes image by reducing the number of colors used in image";
+}
+
+void f0r_get_param_info(f0r_param_info_t* info, int param_index)
+{
+ switch(param_index)
+ {
+ case 0:
+ info->name = "levels"; // range 2 - 50
+ info->type = F0R_PARAM_DOUBLE;
+ info->explanation = "Number of values per channel";
+ break;
+ }
+}
+
+f0r_instance_t f0r_construct(unsigned int width, unsigned int height)
+{
+ posterize_instance_t* inst = (posterize_instance_t*)calloc(1, sizeof(*inst));
+ inst->width = width; 
+ inst->height = height;
+ inst->levels = 5.0;
+ return (f0r_instance_t)inst;
+}
+
+void f0r_destruct(f0r_instance_t instance)
+{
+ free(instance);
+}
+
+void f0r_set_param_value(f0r_instance_t instance, 
+ f0r_param_t param, int param_index)
+{
+ assert(instance);
+ posterize_instance_t* inst = (posterize_instance_t*)instance;
+
+ switch(param_index)
+ {
+ case 0:
+ inst->levels = *((double*)param);
+ break;
+ }
+}
+
+void f0r_get_param_value(f0r_instance_t instance,
+ f0r_param_t param, int param_index)
+{
+ assert(instance);
+ posterize_instance_t* inst = (posterize_instance_t*)instance;
+ 
+ switch(param_index)
+ {
+ case 0:
+ *((double*)param) = inst->levels;
+ break;
+ }
+}
+
+void f0r_update(f0r_instance_t instance, double time,
+ const uint32_t* inframe, uint32_t* outframe)
+{
+ assert(instance);
+ posterize_instance_t* inst = (posterize_instance_t*)instance;
+ unsigned int len = inst->width * inst->height;
+
+ // create levels table
+ int numLevels = (int)inst->levels;
+ numLevels = CLAMP(numLevels, 2, 50);// "working" range of values for this param
+ unsigned char levels[256];
+ int i;
+ for (i = 0; i < 256; i++)
+ {
+ levels[i] = 255 * (numLevels*i / 256) / (numLevels-1);
+ }
+
+ unsigned char* dst = (unsigned char*)outframe;
+ const unsigned char* src = (unsigned char*)inframe;
+ unsigned char r,g,b = 0;
+ while (len--)
+ {
+ r = *src++;
+ g = *src++;
+ b = *src++;
+
+ r = levels[r];
+ g = levels[g];
+ b = levels[b];
+
+ *dst++ = r;
+ *dst++ = g;
+ *dst++ = b;
+ *dst++ = *src++;//copy alpha
+ }
+}
+