[gegl] operations: add gegl:copy-buffer which allows to take snapshots

[Michael Natterer <mitch src gnome org>]

commit 0afc3030341ce5e243c4c0f21b2e0e28e370e212
Author: Michael Natterer <mitch gimp org>
Date:   Sun Jun 1 18:32:21 2014 +0200

    operations: add gegl:copy-buffer which allows to take snapshots
    
    of a graph at any point. It works like gegl:write-buffer but is a
    filter that outputs its input unchanged.

 operations/common/Makefile.am   |    1 +
 operations/common/copy-buffer.c |  171 +++++++++++++++++++++++++++++++++++++++
 po/POTFILES.in                  |    1 +
 3 files changed, 173 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/Makefile.am b/operations/common/Makefile.am
index 92eb897..67cdc6e 100644
--- a/operations/common/Makefile.am
+++ b/operations/common/Makefile.am
@@ -31,6 +31,7 @@ op_LTLIBRARIES = \
        color.la \
        contrast-curve.la \
        convolution-matrix.la \
+       copy-buffer.la \
        cubism.la \
        deinterlace.la \
        difference-of-gaussians.la \
diff --git a/operations/common/copy-buffer.c b/operations/common/copy-buffer.c
new file mode 100644
index 0000000..75c307b
--- /dev/null
+++ b/operations/common/copy-buffer.c
@@ -0,0 +1,171 @@
+/* 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 Øyvind Kolås <pippin gimp org>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+
+#ifdef GEGL_PROPERTIES
+
+property_object (buffer, _("Buffer"), GEGL_TYPE_BUFFER)
+    description(_("An already existing GeglBuffer to write incoming buffer data to, or NULL."))
+
+#else
+
+#define GEGL_OP_FILTER
+#define GEGL_OP_C_FILE "copy-buffer.c"
+
+#include "gegl-op.h"
+
+#include "gegl/gegl-debug.h"
+#include "opencl/gegl-cl.h"
+#include "gegl-buffer-cl-iterator.h"
+
+static void
+prepare (GeglOperation *operation)
+{
+  const Babl *format = gegl_operation_get_source_format (operation, "input");
+
+  if (! format)
+    format = babl_format ("RGBA float");
+
+  gegl_operation_set_format (operation, "input",  format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *result,
+         gint                 level)
+{
+  GeglProperties *o = GEGL_PROPERTIES (operation);
+
+  if (o->buffer)
+    {
+      GeglBuffer *buffer = GEGL_BUFFER (o->buffer);
+      const Babl *in_format = gegl_buffer_get_format (input);
+      const Babl *out_format = gegl_buffer_get_format (buffer);
+
+      if (gegl_operation_use_opencl (operation)
+          && gegl_cl_color_supported (in_format, out_format) == GEGL_CL_COLOR_CONVERT)
+        {
+          size_t size;
+          gboolean err;
+          cl_int cl_err = 0;
+
+          GeglBufferClIterator *i = gegl_buffer_cl_iterator_new (buffer,
+                                                                 result,
+                                                                 out_format,
+                                                                 GEGL_CL_BUFFER_WRITE);
+
+          gint read = gegl_buffer_cl_iterator_add (i,
+                                                   input,
+                                                   result,
+                                                   out_format,
+                                                   GEGL_CL_BUFFER_READ,
+                                                   GEGL_ABYSS_NONE);
+
+          gegl_cl_color_babl (out_format, &size);
+
+          GEGL_NOTE (GEGL_DEBUG_OPENCL,
+                     "write-buffer: "
+                     "%p %p %s %s {%d %d %d %d}",
+                     input,
+                     buffer,
+                     babl_get_name (in_format),
+                     babl_get_name (out_format),
+                     result->x,
+                     result->y,
+                     result->width,
+                     result->height);
+
+          while (gegl_buffer_cl_iterator_next (i, &err))
+            {
+              if (err) break;
+
+              cl_err = gegl_clEnqueueCopyBuffer (gegl_cl_get_command_queue (),
+                                                 i->tex[read],
+                                                 i->tex[0],
+                                                 0,
+                                                 0,
+                                                 i->size[0] * size,
+                                                 0,
+                                                 NULL,
+                                                 NULL);
+
+              if (cl_err != CL_SUCCESS)
+                {
+                  GEGL_NOTE (GEGL_DEBUG_OPENCL, "Error: %s", gegl_cl_errstring (cl_err));
+                  break;
+                }
+            }
+
+          if (cl_err || err)
+            gegl_buffer_copy (input, result, buffer, result);
+        }
+      else
+        gegl_buffer_copy (input, result, buffer, result);
+    }
+
+  if (output)
+    gegl_buffer_copy (input, result, output, result);
+
+  return TRUE;
+}
+
+static void
+dispose (GObject *object)
+{
+  GeglProperties *o = GEGL_PROPERTIES (object);
+
+  if (o->buffer)
+    {
+      g_object_unref (o->buffer);
+      o->buffer = NULL;
+    }
+
+  G_OBJECT_CLASS (gegl_op_parent_class)->dispose (object);
+}
+
+static void
+gegl_op_class_init (GeglOpClass *klass)
+{
+  GObjectClass             *object_class;
+  GeglOperationClass       *operation_class;
+  GeglOperationFilterClass *filter_class;
+
+  object_class    = G_OBJECT_CLASS (klass);
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  filter_class    = GEGL_OPERATION_FILTER_CLASS (klass);
+
+  object_class->dispose     = dispose;
+  operation_class->prepare  = prepare;
+  operation_class->no_cache = TRUE;
+  filter_class->process     = process;
+
+  gegl_operation_class_set_keys (operation_class,
+    "name",        "gegl:copy-buffer",
+    "title",       _("Copy Buffer"),
+    "categories" , "programming",
+    "description", _("Writes image data to an already existing buffer"),
+    NULL);
+}
+
+#endif
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 5c124a0..7d8336d 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -25,6 +25,7 @@ operations/common/color-temperature.c
 operations/common/color-to-alpha.c
 operations/common/contrast-curve.c
 operations/common/convolution-matrix.c
+operations/common/copy-buffer.c
 operations/common/cubism.c
 operations/common/deinterlace.c
 operations/common/difference-of-gaussians.c