[gegl] Added fast path to a stand-alone over op itself

[Øyvind Kolås <ok src gnome org>]

commit f26289c1036a11fa9287fb1422b0faa9c0c4e208
Author: �yvind Kolås <pippin gimp org>
Date:   Thu Nov 12 02:27:44 2009 +0000

    Added fast path to a stand-alone over op itself

 operations/common/over.c            |  184 +++++++++++++++++++++++++++++++++++
 operations/generated/other-blend.rb |    6 +-
 2 files changed, 187 insertions(+), 3 deletions(-)
---
diff --git a/operations/common/over.c b/operations/common/over.c
new file mode 100644
index 0000000..d026dac
--- /dev/null
+++ b/operations/common/over.c
@@ -0,0 +1,184 @@
+/* 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 2006-2009 �yvind Kolås <pippin gimp org>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+/* no properties */
+
+#else
+
+#define GEGL_CHANT_TYPE_POINT_COMPOSER
+#define GEGL_CHANT_C_FILE        "over.c"
+
+#include "gegl-chant.h"
+
+static void prepare (GeglOperation *operation)
+{
+  Babl *format = babl_format ("RaGaBaA float");
+
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "aux", format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static gboolean
+process (GeglOperation        *op,
+          void                *in_buf,
+          void                *aux_buf,
+          void                *out_buf,
+          glong                n_pixels,
+          const GeglRectangle *roi)
+{
+  gint i;
+  gfloat *in = in_buf;
+  gfloat *aux = aux_buf;
+  gfloat *out = out_buf;
+
+  if (aux==NULL)
+    return TRUE;
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      gint   j;
+      gfloat aA, aB, aD;
+
+      aB = in[3];
+      aA = aux[3];
+      aD = aA + aB - aA * aB;
+
+      for (j = 0; j < 3; j++)
+        {
+          gfloat cA, cB;
+
+          cB = in[j];
+          cA = aux[j];
+          out[j] = cA + cB * (1 - aA);
+        }
+      out[3] = aD;
+      in  += 4;
+      aux += 4;
+      out += 4;
+    }
+  return TRUE;
+}
+
+#ifdef HAS_G4FLOAT
+
+static gboolean
+process_gegl4float (GeglOperation      *op,
+                    void               *in_buf,
+                    void                *aux_buf,
+                    void                *out_buf,
+                    glong                n_pixels,
+                    const GeglRectangle *roi)
+{
+  g4float *A = aux_buf;
+  g4float *B = in_buf;
+  g4float *D = out_buf;
+
+  if (B==NULL || n_pixels == 0)
+    return TRUE;
+
+  while (n_pixels--)
+    {
+      *D = *A + *B * (g4float_one - g4float_all(g4float_a(*A)[3]));
+
+      A++; B++; D++;
+    }
+
+  return TRUE;
+}
+
+#endif
+
+/* Fast paths */
+static gboolean operation_process (GeglOperation        *operation,
+                                   GeglOperationContext *context,
+                                   const gchar          *output_prop,
+                                   const GeglRectangle  *result)
+{
+  GeglOperationClass  *operation_class;
+  gpointer input, aux;
+  operation_class = GEGL_OPERATION_CLASS (gegl_chant_parent_class);
+
+  /* get the raw values this does not increase the reference count */
+  input = gegl_operation_context_get_object (context, "input");
+  aux = gegl_operation_context_get_object (context, "aux");
+
+  /* pass the input/aux buffers directly through if they are alone*/
+  {
+    const GeglRectangle *in_extent = NULL;
+    const GeglRectangle *aux_extent = NULL;
+
+    if (input)
+      in_extent = gegl_buffer_get_abyss (input);
+
+    if ((!input ||
+        (aux && !gegl_rectangle_intersect (NULL, in_extent, result))))
+      {
+         gegl_operation_context_take_object (context, "output",
+                                             g_object_ref (aux));
+         return TRUE;
+      }
+    if (aux)
+      aux_extent = gegl_buffer_get_abyss (aux);
+
+    if (!aux ||
+        (input && !gegl_rectangle_intersect (NULL, aux_extent, result)))
+      {
+        gegl_operation_context_take_object (context, "output",
+                                            g_object_ref (input));
+        return TRUE;
+      }
+  }
+  /* chain up, which will create the needed buffers for our actual
+   * process function
+   */
+  return operation_class->process (operation, context, output_prop, result);
+}
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass              *operation_class;
+  GeglOperationPointComposerClass *point_composer_class;
+
+  operation_class      = GEGL_OPERATION_CLASS (klass);
+  point_composer_class = GEGL_OPERATION_POINT_COMPOSER_CLASS (klass);
+  operation_class->prepare = prepare;
+  operation_class->process = operation_process;
+
+  point_composer_class->process = process;
+
+#ifdef HAS_G4FLOAT
+  gegl_operation_class_add_processor (operation_class,
+                                      G_CALLBACK (process_gegl4float), "simd");
+#endif
+
+
+  operation_class->name        = "gegl:over";
+  operation_class->description =
+        _("Porter Duff operation over (d = cA + cB * (1 - aA))");
+  operation_class->categories  = "compositors:porter-duff";
+}
+
+#endif
diff --git a/operations/generated/other-blend.rb b/operations/generated/other-blend.rb
index 7f8ac49..8eb280b 100755
--- a/operations/generated/other-blend.rb
+++ b/operations/generated/other-blend.rb
@@ -37,9 +37,9 @@ a = [
                   'aA + aB - aA * aB',
                   '*D = *A + *B * (g4float_one - g4float_all(g4float_a(*A)[3]))'],
 #       Alias for porter-duff src-over
-      ['over',    'cA + cB * (1 - aA)',
-                  'aA + aB - aA * aB',
-                  '*D = *A + *B * (g4float_one - g4float_all(g4float_a(*A)[3]))'],
+#      ['over',    'cA + cB * (1 - aA)',
+#                  'aA + aB - aA * aB',
+#                  '*D = *A + *B * (g4float_one - g4float_all(g4float_a(*A)[3]))'],
     ]
 
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