From BlenderWiki
This page shows how to intercept every draw call in blenders python ui which can be used for some UI tricks.
First heres an example of how to do just that.
Tested to work with Blender 2.70
Intercept UI draw/poll
This is a simple example of how to intercept poll and draw functions, without making any behavioral changes.
classes = ["Panel", "Menu", "Header"] def draw_override(func_orig, self_real, context): print("override draw:", self_real) ret = func_orig(self_real, context) return ret def poll_override(func_orig, cls, context): print("override poll:", func_orig.__self__) ret = func_orig(context) return ret import bpy for cls_name in classes: cls = getattr(bpy.types, cls_name) for subcls in cls.__subclasses__(): if "draw" in subcls.__dict__: # dont want to get parents draw() def replace_draw(): # function also serves to hold draw_orig in a local namespace draw_orig = subcls.draw def draw(self, context): return draw_override(draw_orig, self, context) subcls.draw = draw replace_draw() if "poll" in subcls.__dict__: # dont want to get parents poll() def replace_poll(): # function also serves to hold poll_orig in a local namespace poll_orig = subcls.poll def poll(cls, context): return poll_override(poll_orig, cls, context) subcls.poll = classmethod(poll) replace_poll()
Override layout & functions
This is the extended from the above code but extended to subclass the layout type used within draw().
In this example operators and properties are filtered out based on their names, but all sorts of things are possible with this - modifying args to functions, changing text etc.
classes = ["Panel", "Menu", "Header"] import bpy UILayout = bpy.types.UILayout op_blacklist = [ "render.render", "object.modifier_add", "object.forcefield_toggle", ] prop_blacklist = [ "Object.location", "Object.scale", "Object.rotation_euler", "RenderSettings.display_mode", ] def filter_operator(op_id): if op_id in op_blacklist: return False return True def filter_prop(data, prop): prop_id = "%s.%s" % (data.__class__.__name__, prop) if prop_id in prop_blacklist: return False return True class OperatorProperties_FAKE: pass class UILayout_FAKE(bpy.types.UILayout): __slots__ = () def __getattribute__(self, attr): # ensure we always pass down UILayout_FAKE instances if attr in ("row", "split", "column", "box", "column_flow"): real_func = UILayout.__getattribute__(self, attr) def dummy_func(*args, **kw): print(" wrapped", attr) ret = real_func(*args, **kw) return UILayout_FAKE(ret) return dummy_func elif attr in ("operator", "operator_menu_enum", "operator_enum"): real_func = UILayout.__getattribute__(self, attr) def dummy_func(*args, **kw): print(" wrapped", attr) if filter_operator(args[0]): ret = real_func(*args, **kw) else: # UILayout.__getattribute__(self, "label")() # may need to be set ret = OperatorProperties_FAKE() return ret return dummy_func elif attr in ("prop", "prop_enum"): real_func = UILayout.__getattribute__(self, attr) def dummy_func(*args, **kw): print(" wrapped", attr) if filter_prop(args[0], args[1]): ret = real_func(*args, **kw) else: ret = None return ret return dummy_func else: return UILayout.__getattribute__(self, attr) print(self, attr) def operator(*args, **kw): print("OP") return super().operator(*args, **kw) def draw_override(func_orig, self_real, context): if 1: class Wrapper(self_real.__class__): def __getattribute__(self, attr): if attr == "layout": ret = self_real.layout return UILayout_FAKE(ret) else: return super().__getattr__(self, attr) @property def layout(self): ret = self_real.layout print("wrapped") return ret print(1) self_wrap = Wrapper(self_real) ret = func_orig(self_wrap, context) else: # simple, no wrapping ret = func_orig(self_wrap, context) return ret def poll_override(func_orig, context): ret = func_orig(context) return ret for cls_name in classes: cls = getattr(bpy.types, cls_name) for subcls in cls.__subclasses__(): if "draw" in subcls.__dict__: # dont want to get parents draw() def replace_draw(): # function also serves to hold draw_old in a local namespace draw_orig = subcls.draw def draw(self, context): return draw_override(draw_orig, self, context) subcls.draw = draw replace_draw() if "poll" in subcls.__dict__: # dont want to get parents poll() def replace_poll(): # function also serves to hold draw_old in a local namespace poll_orig = subcls.poll def poll(context): return poll_override(poll_orig, context) subcls.poll = classmethod(poll) replace_poll()