[gegl/soc-2012-ops: 11/13] Oilify Operation

[Michael Murà <mmure src gnome org>]

commit ba5d3aeca78142af7c1f8e61eed3134e2144d05f
Author: Hans Lo <hansshulo gmail com>
Date:   Thu Jul 5 03:07:08 2012 -0400

    Oilify Operation
    
    Works but no intensity mode yet. Slow probably due to frequent sampling.

 operations/common/oilify.c |  196 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 196 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/oilify.c b/operations/common/oilify.c
new file mode 100644
index 0000000..3c9b100
--- /dev/null
+++ b/operations/common/oilify.c
@@ -0,0 +1,196 @@
+/* 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 1995 Spencer Kimball and Peter Mattis
+ * Copyright 1996 Torsten Martinsen
+ * Copyright 2007 Daniel Richard G.
+ * Copyright 2011 Hans Lo <hansshulo gmail com>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_double (mask_radius, _("Mask Radius"), 1.0, 25.0, 4.0,
+                   _("Radius of circle around pixel"))
+
+gegl_chant_double (exponent, _("Exponent"), 1.0, 20.0, 8.0,
+                   _("Exponent"))
+
+gegl_chant_enum (sampler_type, _("Sampler"), GeglSamplerType, gegl_sampler_type,
+                 GEGL_SAMPLER_CUBIC, _("Sampler used internally"))
+
+#else
+
+#define GEGL_CHANT_TYPE_AREA_FILTER
+#define GEGL_CHANT_C_FILE       "oilify.c"
+
+#include "gegl-chant.h"
+#include <math.h>
+#include <stdlib.h>
+
+#define NUM_INTENSITIES       256
+
+static void oilify_pixel (gint x,
+			  gint y,
+			  gdouble radius,
+			  gdouble exponent,
+			  GeglSampler *sampler,
+			  gfloat *dst_pixel)
+{
+  gint hist[4][NUM_INTENSITIES];
+  gfloat temp_pixel[4];
+  gint ceil_radius = ceil(radius);
+  gdouble radius_sq = radius*radius;
+  gint i, j, b;
+  gint hist_max[4];
+  gint intensity;
+  gfloat sum;
+  gfloat div;
+  
+  for (b = 0; b < 4; b++)
+    {
+      for (i = 0; i < NUM_INTENSITIES; i++)
+	hist[b][i] = 0;
+    }
+  for (i = -ceil_radius; i < ceil_radius; i++)
+    {
+      for (j = -ceil_radius; j < ceil_radius; j++)
+	{
+	  if (i*i + j*j < radius_sq) {
+	    gegl_sampler_get (sampler,
+			      x+i,
+			      y+j,
+			      NULL,
+			      temp_pixel);
+	    for (b = 0; b < 4; b++) 
+	      {
+		intensity = temp_pixel[b] * NUM_INTENSITIES;
+		hist[b][intensity]++;
+	      }
+	  }
+	}
+    }
+  
+  for (b = 0; b < 4; b++) 
+    {
+      hist_max[b] = 1;
+      for (i = 0; i < NUM_INTENSITIES; i++) {
+	hist_max[b] = MAX (hist_max[b], hist[b][i]);
+      }
+  }
+  
+  for (b = 0; b < 4; b++) 
+    {
+      sum = 0.0;
+      div = 0.0;
+      for (i = 0; i < NUM_INTENSITIES; i++)
+	{
+	  gfloat ratio = (gfloat) hist[b][i] / (gfloat) hist_max[b];
+	  gfloat weight = pow (ratio, exponent);
+	  sum += weight * (gfloat) i/(gfloat) NUM_INTENSITIES;
+	  div += weight;
+	}
+      dst_pixel[b] = sum / div;
+    }
+}
+
+static void prepare (GeglOperation *operation)
+{
+  GeglChantO              *o;
+  GeglOperationAreaFilter *op_area;
+
+  op_area = GEGL_OPERATION_AREA_FILTER (operation);
+  o       = GEGL_CHANT_PROPERTIES (operation);
+
+  op_area->left   = 
+  op_area->right  = 
+  op_area->top    = 
+  op_area->bottom = o->mask_radius;
+
+  gegl_operation_set_format (operation, "input",
+                             babl_format ("RGBA float"));
+  gegl_operation_set_format (operation, "output",
+                             babl_format ("RGBA float"));
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *result,
+         gint                 level)
+{
+  GeglChantO *o                    = GEGL_CHANT_PROPERTIES (operation);
+
+  gint x = result->x; /* initial x                   */
+  gint y = result->y; /*           and y coordinates */
+  
+  gfloat *dst_buf = g_slice_alloc (result->width * result->height * 4 * sizeof(gfloat));
+
+  gfloat *out_pixel = dst_buf;
+
+  GeglSampler *sampler = gegl_buffer_sampler_new (input,
+                                                  babl_format ("RGBA float"),
+                                                  o->sampler_type);
+
+  gint n_pixels = result->width * result->height;
+
+  while (n_pixels--)
+    {
+      
+      oilify_pixel(x, y, o->mask_radius, o->exponent, sampler, out_pixel);
+
+      out_pixel += 4;
+
+      /* update x and y coordinates */
+      x++;
+      if (x>=result->x + result->width)
+        {
+          x=result->x;
+          y++;
+        }
+    }
+
+  gegl_buffer_set (output, result, 0, babl_format ("RGBA float"), dst_buf, GEGL_AUTO_ROWSTRIDE);
+  g_slice_free1 (result->width * result->height * 4 * sizeof(gfloat), dst_buf);
+
+  g_object_unref (sampler);
+
+  return  TRUE;
+}
+
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass       *operation_class;
+  GeglOperationFilterClass *filter_class;
+
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  filter_class    = GEGL_OPERATION_FILTER_CLASS (klass);
+
+  filter_class->process    = process;
+  operation_class->prepare = prepare;
+
+  gegl_operation_class_set_keys (operation_class,
+    "categories" , "artistic",
+    "name"       , "gegl:oilify",
+    "description", _("Emulate an oil painting"),
+    NULL);
+}
+
+#endif