added class methods to python

we now have Vips.Image.black(w, h), woo

TODO

@@ -1,27 +1,6 @@
 
 - python:
 
-	- can we override __getattr__ on a type object?
-
-		Vips.Image.black
-		AttributeError: type object 'Image' has no attribute 'black'
-
-	  we'd like to attack black as a class method, or override __getattr__
-	  to let us patch class methods in
-
-	  looks like defining a metaclass might do it, but 
-
- 	  	Vips.Image.__metaclass__ = ImageType
-		setattr(Vips.Image, '__metaclass__', ImageType)
-		setattr(Vips.Image, '__metaclass__', classmethod(ImageType))
-
-	  don't work, nor any other obvious variations
-
-	  we could walk all vips operators and paste in ones without an
-	  image instance arg as class methods, but that would be very slow and
-	  wouldn't work for loading plugins
-
-
 	- how about the in-place things? draw a circle?
 
 	- try getting / setting / deleting metadata such as an ICC profile or

libvips/include/vips/object.h

@@ -618,6 +618,7 @@ void *vips_type_map( GType base, VipsTypeMap2Fn fn, void *a, void *b );
 void *vips_type_map_all( GType base, VipsTypeMapFn fn, void *a );
 int vips_type_depth( GType type );
 GType vips_type_find( const char *basename, const char *nickname );
+const char *vips_nickname_find( GType type );
 
 void *vips_class_map_all( GType base, VipsClassMapFn fn, void *a );
 VipsObjectClass *vips_class_find( const char *basename, const char *nickname );

libvips/iofuncs/object.c

@@ -2746,6 +2746,29 @@ vips_type_find( const char *basename, const char *nickname )
 	return( type );
 }
 
+/**
+ * vips_nickname_find:
+ * @type: #GType to search for
+ *
+ * Return the VIPS nickanme for a %GType. Handy for language bindings. 
+ *
+ * Returns: (transfer none): the class nickname. 
+ */
+const char *
+vips_nickname_find( GType type )
+{
+	gpointer p;
+	VipsObjectClass *class;
+
+	if( type &&
+		(p = g_type_class_ref( type )) &&
+		VIPS_IS_OBJECT_CLASS( p ) &&
+		(class = VIPS_OBJECT_CLASS( p )) )
+		return( class->nickname );
+
+	return( NULL );
+}
+
 /* The vips_object_local() macro uses this as its callback.
  */
 void

python/try9.py

@@ -5,8 +5,6 @@ import sys
 import logging
 logging.basicConfig(level = logging.DEBUG)
 
-from gi.repository import GLib
-from gi.repository import GObject
 from gi.repository import Vips 
 
 from vips8 import vips

python/vips8/vips.py

@@ -397,7 +397,7 @@ setattr(Vips.Image, 'new_from_buffer', classmethod(vips_image_new_from_buffer))
 setattr(Vips.Image, 'new_from_array', classmethod(vips_image_new_from_array))
 
 # yuk, we should run these via a metaclass somehow
-setattr(Vips.Image, 'black', classmethod(vips_black))
+#setattr(Vips.Image, 'black', classmethod(vips_black))
 
 # Search for all VipsOperation which don't have an input image object ... these
 # become class methods
@@ -405,7 +405,10 @@ setattr(Vips.Image, 'black', classmethod(vips_black))
 def vips_image_class_method(name, args, kwargs):
     logging.debug('vips_image_class_method %s' % name)
 
-    return _call_instance(None, name, args, kwargs)
+    # the first arg is the class we are called from ... drop it
+    args = tuple(list(args)[1::])
+
+    return _call_base(name, args, kwargs)
 
 def define_class_methods(cls):
     if len(cls.children) > 0:
@@ -424,8 +427,11 @@ def define_class_methods(cls):
                     break
 
         if not found:
-            print 'operation %s has no input image args' % cls.name
-            setattr(Vips.Image, cls.name, classmethod(lambda *args, **kwargs: vips_image_class_method(cls.name, args, kwargs)))
+            gtype = Vips.type_find("VipsOperation", cls.name)
+            nickname = Vips.nickname_find(gtype)
+            logging.debug('adding %s as a class method' % nickname)
+            method = lambda *args, **kwargs: vips_image_class_method( nickname, args, kwargs)
+            setattr(Vips.Image, nickname, classmethod(method))
 
 define_class_methods(vips_type_operation)