[gegl/soc-2012-ops: 5/58] Photocopy Operation

[Michael Murà <mmure src gnome org>]

commit ce6dc96e1700ae9ff6bf41bbb89dfa4ce021bead
Author: Hans Lo <hansshulo gmail com>
Date:   Sat Jun 23 03:10:54 2012 -0400

    Photocopy Operation
    
    Runs but not finished yet.

 operations/common/photocopy.c |  257 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 257 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/photocopy.c b/operations/common/photocopy.c
new file mode 100644
index 0000000..293fcf0
--- /dev/null
+++ b/operations/common/photocopy.c
@@ -0,0 +1,257 @@
+/* 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 1997 Spencer Kimball
+ * 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"), 0.0, 50.0, 10.0,
+                   _("Mask Radius"))
+
+gegl_chant_double (sharpness, _("Sharpness"), 0.0, 1.0, 0.5,
+                   _("Sharpness"))
+
+gegl_chant_double (black, _("Percent Black"), 0.0, 1.0, 0.2,
+                   _("Percent Black"))
+
+gegl_chant_double (white, _("Percent White"), 0.0, 1.0, 0.2,
+                   _("Percent White"))
+
+#else
+
+#define GEGL_CHANT_TYPE_AREA_FILTER
+#define GEGL_CHANT_C_FILE       "photocopy.c"
+
+#include "gegl-chant.h"
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+#define THRESHOLD 0.75
+
+static void prepare (GeglOperation *operation)
+{
+  GeglChantO              *o;
+  GeglOperationAreaFilter *op_area;
+
+  op_area = GEGL_OPERATION_AREA_FILTER (operation);
+  o       = GEGL_CHANT_PROPERTIES (operation);
+
+  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);
+
+  GeglNode *gegl, *image, *write1, *write2, *grey, *blur1, *blur2;
+  GeglBuffer *dest1 = gegl_buffer_new(result, babl_format ("Y float"));
+  GeglBuffer *dest2 = gegl_buffer_new(result, babl_format ("Y float"));
+
+  gegl = gegl_node_new();
+  image = gegl_node_new_child(gegl,
+			      "operation", "gegl:buffer-source",
+			      "buffer", input,
+			      NULL);
+
+  grey = gegl_node_new_child(gegl,
+			     "operation", "gegl:grey",
+			     NULL);
+
+  blur1 =  gegl_node_new_child(gegl,
+			       "operation", "gegl:gaussian-blur",
+			       "std_dev_x", 1.0 - o->sharpness,
+			       "std_dev_y", 1.0 - o->sharpness,
+			       NULL);
+  
+  blur2 =  gegl_node_new_child(gegl,
+			       "operation", "gegl:gaussian-blur",
+			       "std_dev_x", o->mask_radius,
+			       "std_dev_y", o->mask_radius,
+			       NULL);
+  
+  write1 = gegl_node_new_child(gegl,
+			      "operation", "gegl:buffer-sink",
+			      "buffer", &dest1, NULL);
+  
+  write2 = gegl_node_new_child(gegl,
+			      "operation", "gegl:buffer-sink",
+			      "buffer", &dest2, NULL);
+  
+
+  gegl_node_link_many (image, grey, blur1, write1, NULL);
+  gegl_node_process (write1);
+  
+  gegl_node_link_many (image, grey, blur2, write2, NULL);
+  gegl_node_process (write2);
+  
+  GeglSampler *sampler1 = gegl_buffer_sampler_new (dest1,
+                                                  babl_format ("Y float"),
+                                                  GEGL_SAMPLER_CUBIC);
+  GeglSampler *sampler2 = gegl_buffer_sampler_new (dest2,
+                                                  babl_format ("Y float"),
+                                                  GEGL_SAMPLER_CUBIC);
+
+  gfloat *dst_buf = g_slice_alloc (result->width * result->height * 1 * sizeof(gfloat));
+  
+  gint n_pixels = result->width * result->height;
+  
+  gfloat pixel1, pixel2;
+
+  gfloat *out_pixel = dst_buf;
+
+  gint x = result->x; /* initial x                   */
+  gint y = result->y; /*           and y coordinates */
+
+  gdouble diff;
+
+  while (n_pixels--)
+    {
+      gegl_sampler_get (sampler1,
+			x,
+                        y,
+                        NULL,
+                        &pixel1);
+
+      gegl_sampler_get (sampler2,
+                        x,
+                        y,
+                        NULL,
+                        &pixel2);
+      diff = pixel1/pixel2;
+      if (diff < THRESHOLD)
+	{
+	  *out_pixel = 1.0;
+	} 
+      else
+	{
+	  *out_pixel = pixel1;
+	}
+      out_pixel += 1;
+      
+      /* update x and y coordinates */
+      x++;
+      if (x>=result->x + result->width)
+        {
+          x=result->x;
+          y++;
+        }
+    }
+  
+  gegl_buffer_set (output, result, 0, babl_format ("Y float"), dst_buf, GEGL_AUTO_ROWSTRIDE);
+  g_slice_free1 (result->width * result->height * 1 * sizeof(gfloat), dst_buf);
+  g_object_unref (sampler1);
+  g_object_unref (sampler2);
+
+  g_object_unref (gegl);
+  return  TRUE;
+}
+
+static gdouble
+compute_ramp (guchar  *dest1,
+              guchar  *dest2,
+	      gint     length,
+              gdouble  pct,
+              gint     under_threshold)
+{
+  gint    hist[2000];
+  gdouble diff;
+  gint    count;
+  gint    i;
+  gint    sum;
+
+  memset (hist, 0, sizeof (int) * 2000);
+  count = 0;
+
+  for (i = 0; i < length; i++)
+    {
+      if (*dest2 != 0)
+        {
+          diff = (gdouble) *dest1 / (gdouble) *dest2;
+
+          if (under_threshold)
+            {
+              if (diff < THRESHOLD)
+                {
+                  hist[(int) (diff * 1000)] += 1;
+                  count += 1;
+                }
+            }
+          else
+            {
+              if (diff >= THRESHOLD && diff < 2.0)
+                {
+                  hist[(int) (diff * 1000)] += 1;
+                  count += 1;
+                }
+            }
+        }
+
+      dest1++;
+      dest2++;
+    }
+
+  if (pct == 0.0 || count == 0)
+    return (under_threshold ? 1.0 : 0.0);
+
+  sum = 0;
+  for (i = 0; i < 2000; i++)
+    {
+      sum += hist[i];
+      if (((gdouble) sum / (gdouble) count) > pct)
+        {
+          if (under_threshold)
+            return (THRESHOLD - (gdouble) i / 1000.0);
+          else
+            return ((gdouble) i / 1000.0 - THRESHOLD);
+        }
+    }
+
+  return (under_threshold ? 0.0 : 1.0);
+}
+
+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);
+
+  operation_class->prepare = prepare;
+  filter_class->process    = process;
+
+  gegl_operation_class_set_keys (operation_class,
+    "categories" , "artistic",
+    "name"       , "gegl:photocopy",
+    "description", _("Photocopy effect"),
+    NULL);
+}
+
+#endif