libgimp: new gimp_pdb_run_procedure_config() function.

While we do have quite a few gimp_pdb_run_procedure*() functions now, I
always felt that one based on a config file was missing, even more as we
are getting further and further into using config objects in plug-ins.

In C, the gimp_pdb_run_procedure() function is without a doubt the
easiest one. But such variable arg functions are not available on
bindings, and having to deal with GValue and GimpValueArray is a real
pain.

Also using a config file has the very great advantage that we don't need
to care about order. For instance, if I need to set the 10th argument of
a PDB call (and leave the rest to default values), I don't have to set
all 9 previous arguments. I can set only this one if I want. This
advantage is useful also for C code by the way.

For the record, here is how you could load then export an image with the
"file-png-*" PDB procedures in Python:

> c = Gimp.get_pdb().lookup_procedure('file-png-load').create_config()
> c.set_property('file', Gio.file_new_for_path('/path/sample.png'))
> r = Gimp.get_pdb().run_procedure_config('file-png-load', c)
> d = Gimp.Display.new(r.index(1)) # Give it a display to work on it.

Now exporting:

> img = r.index(1)
> c = Gimp.get_pdb().lookup_procedure('file-png-save').create_config()
> c.set_property('image', img)
> c.set_property('file', Gio.file_new_for_path('/path/exported.png'))
> layers = img.get_layers()
> c.set_property('drawables', Gimp.ObjectArray.new(Gimp.Drawable, layers, False))
> c.set_property('num-drawables', len(layers))
> r = Gimp.get_pdb().run_procedure_config('file-png-save', c)

libgimp/gimp.def

@@ -680,6 +680,7 @@ EXPORTS
 	gimp_pdb_run_procedure
 	gimp_pdb_run_procedure_argv
 	gimp_pdb_run_procedure_array
+	gimp_pdb_run_procedure_config
 	gimp_pdb_run_procedure_valist
 	gimp_pdb_set_data
 	gimp_pdb_temp_procedure_name

libgimp/gimppdb.c

@@ -362,6 +362,46 @@ gimp_pdb_run_procedure_array (GimpPDB              *pdb,
   return return_values;
 }
 
+/**
+ * gimp_pdb_run_procedure_config:
+ * @pdb:            the #GimpPDB object.
+ * @procedure_name: the registered name to call.
+ * @config:         a config object obtained with gimp_procedure_create_config().
+ *
+ * Runs the procedure named @procedure_name with @config.
+ *
+ * Returns: (transfer full): the return values for the procedure call.
+ *
+ * Since: 3.0
+ */
+GimpValueArray *
+gimp_pdb_run_procedure_config (GimpPDB             *pdb,
+                               const gchar         *procedure_name,
+                               GimpProcedureConfig *config)
+{
+  GimpProcedure  *procedure;
+  GimpValueArray *args;
+  GimpValueArray *return_values;
+
+  g_return_val_if_fail (GIMP_IS_PDB (pdb), NULL);
+  g_return_val_if_fail (gimp_is_canonical_identifier (procedure_name), NULL);
+  g_return_val_if_fail (GIMP_IS_PROCEDURE_CONFIG (config), NULL);
+
+  procedure = gimp_pdb_lookup_procedure (pdb, procedure_name);
+
+  g_return_val_if_fail (gimp_procedure_config_get_procedure (config) == procedure,
+                        NULL);
+
+  args = gimp_procedure_new_arguments (procedure);
+
+  gimp_procedure_config_get_values (config, args);
+  return_values = gimp_pdb_run_procedure_array (pdb, procedure_name, args);
+
+  gimp_value_array_unref (args);
+
+  return return_values;
+}
+
 /**
  * gimp_pdb_temp_procedure_name:
  * @pdb: the #GimpPDB object.

libgimp/gimppdb.h

@@ -88,6 +88,9 @@ GimpValueArray * gimp_pdb_run_procedure_argv   (GimpPDB              *pdb,
 GimpValueArray * gimp_pdb_run_procedure_array  (GimpPDB              *pdb,
                                                 const gchar          *procedure_name,
                                                 const GimpValueArray *arguments);
+GimpValueArray * gimp_pdb_run_procedure_config (GimpPDB              *pdb,
+                                                const gchar          *procedure_name,
+                                                GimpProcedureConfig  *config);
 
 gchar          * gimp_pdb_temp_procedure_name  (GimpPDB              *pdb);