[gegl/soc-2010-cage] add an operation that sample input with an auxiliar buffer that contain source coordinates

[Michael Muré <mmure src gnome org>]

commit 58e03a190eed5dfa53584bad3c23317a3006d0bc
Author: Michael Muré <batolettre gmail com>
Date:   Mon Aug 2 12:07:55 2010 +0200

    add an operation that sample input with an auxiliar buffer that contain source coordinates

 operations/common/render_mapping.c |  133 ++++++++++++++++++++++++++++++++++++
 1 files changed, 133 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/render_mapping.c b/operations/common/render_mapping.c
new file mode 100644
index 0000000..4e8f9d5
--- /dev/null
+++ b/operations/common/render_mapping.c
@@ -0,0 +1,133 @@
+/* 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 2010 Michael Muré <batolettre gmail com>
+ *
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#include <gegl.h>
+#include <gegl-plugin.h>
+#include <gegl-utils.h>
+#include "buffer/gegl-sampler.h"
+#include "buffer/gegl-buffer-iterator.h"
+
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+#else
+
+#define GEGL_CHANT_TYPE_POINT_COMPOSER
+#define GEGL_CHANT_C_FILE       "render_mapping.c"
+
+#include "gegl-chant.h"
+
+
+static void prepare (GeglOperation *operation)
+{
+  Babl *format = babl_format ("RGBA float");
+
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "aux", babl_format_n (babl_type ("float"), 2));
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *aux,
+         GeglBuffer          *output,
+         const GeglRectangle *result)
+{
+  Babl                 *format_io, *format_coords;
+  GeglSampler          *sampler;
+  GType                 desired_type;
+  GeglInterpolation     interpolation;
+  GeglBufferIterator   *it;
+  gint                  index_out, index_coords;
+  
+  format_io = babl_format ("RGBA float");
+  format_coords = babl_format_n (babl_type ("float"), 2);
+  
+  interpolation = gegl_buffer_interpolation_from_string ("cubic");
+  desired_type = gegl_sampler_type_from_interpolation (interpolation);
+  
+  sampler = g_object_new (desired_type,
+                          "format", format_io,
+                          "buffer", input,
+                          NULL);
+  
+  gegl_sampler_prepare (sampler);  
+  
+  if (aux != NULL)
+  {
+    it = gegl_buffer_iterator_new (output, result, format_io, GEGL_BUFFER_WRITE);
+    index_out = 0;
+    
+    index_coords = gegl_buffer_iterator_add (it, aux, result, format_coords, GEGL_BUFFER_READ);
+    
+    while (gegl_buffer_iterator_next (it))
+    {
+      gint        i;
+      gint        n_pixels = it->length;
+      gfloat     *out = it->data[index_out];
+      gfloat     *coords = it->data[index_coords];
+      gfloat     *sample;
+      
+      for (i=0; i<n_pixels; i++)
+      {
+        sample = gegl_sampler_get_from_buffer (sampler, coords[0], coords[1]);
+        
+        out[0] = sample[0];
+        out[1] = sample[1];
+        out[2] = sample[2];
+        out[3] = sample[3];
+        
+        coords += 2;
+        out += 4;
+      }
+    }
+    
+  }
+  else
+  {
+    gegl_buffer_copy (input, result, output, result);
+  }
+  
+  g_object_unref (sampler);
+  
+  return TRUE;
+}
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass         *operation_class;
+  GeglOperationComposerClass *composer_class;
+
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  composer_class  = GEGL_OPERATION_COMPOSER_CLASS (klass);
+
+  composer_class->process = process;
+  operation_class->prepare = prepare;
+  
+  operation_class->name        = "gegl:render_mapping";
+  
+  operation_class->categories  = "transform";
+  operation_class->description = _("sample input with an auxiliar buffer that contain source coordinates");
+}
+#endif