Convert on_trait_change decorators to observe

enable/savage/compliance/comparator.py

@@ -27,8 +27,7 @@
 from enable.api import Component
 from enable.component_editor import ComponentEditor
 from traits.api import (
-    Any, Button, Dict, HasTraits, HTML, Instance, List, Property, Str,
-    on_trait_change
+    Any, Button, Dict, HasTraits, HTML, Instance, List, Property, Str, observe
 )
 from traitsui.api import (
     EnumEditor, HGroup, HSplit, Item, Tabbed, VGroup, View, VSplit
@@ -396,10 +395,10 @@ def _get_mouse_coords(self):
         else:
             return "%1.3g %1.3g" % self.ch_controller.svg_coords
 
-    @on_trait_change("profile_this:profile_ended")
-    def _update_profiling(self, new):
-        if new is not None:
-            name, p = new
+    @observe("profile_this:profile_ended")
+    def _update_profiling(self, event):
+        if event.new is not None:
+            name, p = event.new
             stats = pstats.Stats(p)
             if name == "Parsing":
                 self.parsing_sike.stats = stats

enable/savage/compliance/crosshair.py

@@ -11,7 +11,7 @@
 """
 
 from enable.api import BaseTool, ColorTrait, LineStyle
-from traits.api import Bool, Float, HasTraits, List, Tuple, on_trait_change
+from traits.api import Bool, Float, HasTraits, List, Tuple, observe
 
 
 class Crosshair(BaseTool):
@@ -84,8 +84,8 @@ def normal_mouse_move(self, event):
         self.svg_coords = event.x, y
         event.handled = True
 
-    @on_trait_change("svg_coords,mouse_in")
-    def ensure_redraw(self):
+    @observe("svg_coords,mouse_in")
+    def ensure_redraw(self, event=None):
         if self.component is not None:
             self.component.invalidate_and_redraw()
 

enable/savage/compliance/sike.py

@@ -15,7 +15,7 @@
 
 from traits.api import (
     Any, Bool, Constant, Dict, Event, Float, HasTraits, Instance, Int, List,
-    Property, Str, on_trait_change
+    Property, Str, observe
 )
 from traitsui.api import (
     CodeEditor, Group, HGroup, Item, Label, TabularAdapter, TabularEditor,
@@ -208,12 +208,12 @@ def _adapter_default(self):
             total_time=self.total_time,
         )
 
-    @on_trait_change("total_time,percentages,basenames")
-    def _adapter_traits_changed(self, object, name, old, new):
-        setattr(self.adapter, name, new)
+    @observe("total_time,percentages,basenames")
+    def _adapter_traits_changed(self, event):
+        setattr(self.adapter, event.name, event.new)
 
-    @on_trait_change("sort_key,sort_ascending")
-    def _resort(self):
+    @observe("sort_key,sort_ascending")
+    def _resort(self, event=None):
         self.records = self.sort_records(self.records)
 
     def _column_clicked_changed(self, new):
@@ -365,17 +365,18 @@ def get_callee_map(self, records):
                 )
         return callees
 
-    @on_trait_change("percentages,basenames")
-    def _adapter_traits_changed(self, object, name, old, new):
+    @observe("percentages,basenames")
+    def _adapter_traits_changed(self, event):
         for obj in [
             self.main_results,
             self.callee_results,
             self.caller_results,
         ]:
-            setattr(obj, name, new)
+            setattr(obj, event.name, event.new)
 
-    @on_trait_change("main_results:selected_record")
-    def update_sub_results(self, new):
+    @observe("main_results:selected_record")
+    def update_sub_results(self, event):
+        new = event.new
         if new is None:
             return
         self.caller_results.total_time = new.cum_time
@@ -404,16 +405,17 @@ def update_sub_results(self, new):
         else:
             self.trait_set(code="", filename="", line=1)
 
-    @on_trait_change("caller_results:dclicked," "callee_results:dclicked")
-    def goto_record(self, new):
+    @observe("caller_results:dclicked," "callee_results:dclicked")
+    def goto_record(self, event):
+        new = event.new
         if new is None:
             return
         if new.item.file_line_name in self.record_map:
             record = self.record_map[new.item.file_line_name]
             self.main_results.selected_record = record
 
-    @on_trait_change("stats")
-    def _refresh_stats(self):
+    @observe("stats")
+    def _refresh_stats(self, event=None):
         """ Refresh the records from the stored Stats object.
         """
         self.main_results.records = self.main_results.sort_records(

enable/slider.py

@@ -12,7 +12,7 @@
 # Enthought library imports
 from kiva.api import STROKE
 from traits.api import (
-    Any, Bool, Enum, Float, Int, Property, Trait, on_trait_change,
+    Any, Bool, Enum, Float, Int, Property, Trait, observe,
 )
 from traitsui.api import EnumEditor
 
@@ -521,8 +521,8 @@ def _get_endcap_size(self):
     def _get_tick_size(self):
         return self._cached_tick_size
 
-    @on_trait_change("bounds,bounds_items")
-    def _update_sizes(self):
+    @observe("bounds.items")
+    def _update_sizes(self, event=None):
         if self._slider_size_mode == "percent":
             if self.orientation == "h":
                 self._cached_slider_size = int(

enable/text_grid.py

@@ -16,7 +16,7 @@
 
 # Enthought library imports
 from traits.api import (
-    Any, Array, Bool, Int, List, Property, Trait, Tuple, on_trait_change,
+    Any, Array, Bool, Int, List, Property, Trait, Tuple, observe,
 )
 from kiva.trait_defs.api import KivaFont
 
@@ -296,8 +296,8 @@ def _string_array_changed(self, old, new):
         self._compute_positions()
         self._update_bounds()
 
-    @on_trait_change("cell_border_width,cell_padding")
-    def cell_properties_changed(self):
+    @observe("cell_border_width,cell_padding")
+    def cell_properties_changed(self, event=None):
         self._compute_positions()
         self._update_bounds()
 

enable/viewport.py

@@ -17,7 +17,7 @@
 from enable.tools.viewport_zoom_tool import ViewportZoomTool
 from kiva import affine
 from traits.api import (
-    Any, Bool, Delegate, Enum, Float, Instance, on_trait_change,
+    Any, Bool, Delegate, Enum, Float, Instance, observe,
 )
 
 # Local relative imports
@@ -320,20 +320,25 @@ def _component_changed(self, old, new):
             new.viewports.append(self)
             self._update_component_view_bounds()
 
-    @on_trait_change("component:bounds")
-    def _component_bounds_updated(self, obj, name, old, new):
-        if name == "bounds":
-            delta_x = new[0] - old[0]
-            delta_y = new[1] - old[1]
-        elif name == "bounds_items":
-            delta_x = 0
-            delta_y = 0
-            if new.index == 1:
-                delta_y = new.added[0] - new.removed[0]
-            else:
-                delta_x = new.added[0] - new.removed[0]
-                if len(new.removed) == 2:
-                    delta_y = new.added[1] - new.removed[1]
+    @observe("component:bounds")
+    def _updated_component_bounds(self, event):
+        new = event.new
+        old = event.old
+
+        delta_x = new[0] - old[0]
+        delta_y = new[1] - old[1]
+        self._adjust_view_from_component_resize(delta_x, delta_y)
+
+    @observe("component:bounds:items")
+    def _updated_component_bounds_items(self, event):
+        delta_x = 0
+        delta_y = 0
+        if event.index == 1:
+            delta_y = event.added[0] - event.removed[0]
+        else:
+            delta_x = event.added[0] - event.removed[0]
+            if len(event.removed) == 2:
+                delta_y = event.added[1] - event.removed[1]
         self._adjust_view_from_component_resize(delta_x, delta_y)
 
     def _bounds_changed(self, old, new):
@@ -348,8 +353,8 @@ def _bounds_changed(self, old, new):
     def _bounds_items_changed(self, event):
         return self._bounds_changed(None, self.bounds)
 
-    @on_trait_change("view_bounds,view_position")
-    def _handle_view_box_changed(self):
+    @observe("view_bounds,view_position")
+    def _handle_view_box_changed(self, event=None):
         self._update_component_view_bounds()
 
     def _get_position(self):