task 2 - added hover backend implementation & tk specific label

yanxinc · yanxinc · commit 4bdbc5472fcc · 2023-04-28T16:52:31.000-04:00
diff --git a/doc/api/artist_api.rst b/doc/api/artist_api.rst
@@ -44,6 +44,10 @@ Interactive
    Artist.pickable
    Artist.set_picker
    Artist.get_picker
+   Artist.hover
+   Artist.hoverable
+   Artist.set_hover
+   Artist.get_hover
 
 Clipping
 --------
diff --git a/lib/matplotlib/artist.py b/lib/matplotlib/artist.py
@@ -596,34 +596,58 @@ def get_picker(self):
         """
         return self._picker
     
+    def hoverable(self):
+        """
+        Return whether the artist is hoverable.
+
+        See Also
+        --------
+        set_hover, get_hover, hover
+        """
+        return self.figure is not None and self._hover is not None
+    
+    def hover(self, mouseevent):
+        """
+        Process a hover event.
+
+        Each child artist will fire a hover event if *mouseevent* is over
+        the artist and the artist has hover set.
+
+        See Also
+        --------
+        set_hover, get_hover, hoverable
+        """
+        from .backend_bases import HoverEvent  # Circular import.
+        # Hover self
+        if self.hoverable():
+            hoverer = self.get_hover()
+            inside, prop = self.contains(mouseevent)
+            if inside:
+                HoverEvent("hover_event", self.figure.canvas,
+                          mouseevent, self, **prop)._process()
+
+        # Pick children
+        for a in self.get_children():
+            # make sure the event happened in the same Axes
+            ax = getattr(a, 'axes', None)
+            if (mouseevent.inaxes is None or ax is None
+                    or mouseevent.inaxes == ax):
+                a.hover(mouseevent)
+
     def set_hover(self, hover):
         """
         Define the hover status of the artist.
 
         Parameters
         ----------
-        hover : None or bool or float or callable
+        hover : None or bool
             This can be one of the following:
 
             - *None*: Hover is disabled for this artist (default).
 
             - A boolean: If *True* then hover will be enabled and the
               artist will fire a hover event if the mouse event is hovering over
               the artist.
-
-            - A float: If hover is a number it is interpreted as an
-              epsilon tolerance in points and the artist will fire
-              off an event if its data is within epsilon of the mouse
-              event.  For some artists like lines and patch collections,
-              the artist may provide additional data to the hover event
-              that is generated, e.g., the indices of the data within
-              epsilon of the hover event
-
-            - A function: If hover is callable, it is a user supplied
-              function which determines whether the artist is hit by the
-              mouse event to determine the hit test.  if the mouse event 
-              is over the artist, return *hit=True* and props is a dictionary of
-              properties you want added to the HoverEvent attributes.
         """
         self._hover = hover
     
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1744,7 +1744,8 @@ class FigureCanvasBase:
         'figure_leave_event',
         'axes_enter_event',
         'axes_leave_event',
-        'close_event'
+        'close_event',
+        'hover_event'
     ]
 
     fixed_dpi = None
@@ -2295,7 +2296,8 @@ def mpl_connect(self, s, func):
             - 'figure_leave_event',
             - 'axes_enter_event',
             - 'axes_leave_event'
-            - 'close_event'.
+            - 'close_event'
+            - 'hover_event'
 
         func : callable
             The callback function to be executed, which must have the
@@ -3007,9 +3009,19 @@ def _mouse_event_to_message(event):
         return ""
 
     def mouse_move(self, event):
+        from .patches import Rectangle
         self._update_cursor(event)
         self.set_message(self._mouse_event_to_message(event))
 
+        if callable(getattr(self, 'set_hover_message', None)):
+            for a in self.canvas.figure.findobj(match=lambda x: not isinstance(x, Rectangle), include_self=False):
+                inside, prop = a.contains(event)
+                if inside:
+                    self.set_hover_message(self._mouse_event_to_message(event))
+                else:
+                    self.set_hover_message("")
+                break
+
     def _zoom_pan_handler(self, event):
         if self.mode == _Mode.PAN:
             if event.name == "button_press_event":
diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -649,6 +649,12 @@ def __init__(self, canvas, window=None, *, pack_toolbar=True):
                                        justify=tk.RIGHT)
         self._message_label.pack(side=tk.RIGHT)
 
+        self.hover_message = tk.StringVar(master=self)
+        self._hover_label = tk.Label(master=self, font=self._label_font,
+                                       textvariable=self.hover_message,
+                                       justify=tk.RIGHT)
+        self._hover_label.pack(side=tk.RIGHT)
+
         NavigationToolbar2.__init__(self, canvas)
         if pack_toolbar:
             self.pack(side=tk.BOTTOM, fill=tk.X)
@@ -700,6 +706,9 @@ def zoom(self, *args):
     def set_message(self, s):
         self.message.set(s)
 
+    def set_hover_message(self, s):
+        self.hover_message.set(s)
+
     def draw_rubberband(self, event, x0, y0, x1, y1):
         # Block copied from remove_rubberband for backend_tools convenience.
         if self.canvas._rubberband_rect_white:
@@ -976,6 +985,12 @@ def __init__(self, toolmanager, window=None):
         self._message_label = tk.Label(master=self, font=self._label_font,
                                        textvariable=self._message)
         self._message_label.pack(side=tk.RIGHT)
+
+        self._hover_message = tk.StringVar(master=self)
+        self._hover_label = tk.Label(master=self, font=self._label_font,
+                                       textvariable=self._hover_message)
+        self._hover_label.pack(side=tk.RIGHT)
+
         self._toolitems = {}
         self.pack(side=tk.TOP, fill=tk.X)
         self._groups = {}
@@ -1032,6 +1047,8 @@ def remove_toolitem(self, name):
     def set_message(self, s):
         self._message.set(s)
 
+    def set_hover_message(self, s):
+        self._hover_message.set(s)
 
 @backend_tools._register_tool_class(FigureCanvasTk)
 class SaveFigureTk(backend_tools.SaveFigureBase):
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -2519,6 +2519,7 @@ def __init__(self,
         ]
         self._button_pick_id = connect('button_press_event', self.pick)
         self._scroll_pick_id = connect('scroll_event', self.pick)
+        self._hover_id = connect('motion_notify_event', self.hover)
 
         if figsize is None:
             figsize = mpl.rcParams['figure.figsize']
@@ -2566,6 +2567,10 @@ def pick(self, mouseevent):
         if not self.canvas.widgetlock.locked():
             super().pick(mouseevent)
 
+    def hover(self, mouseevent):
+        if not self.canvas.widgetlock.locked():
+            super().hover(mouseevent)
+
     def _check_layout_engines_compat(self, old, new):
         """
         Helper for set_layout engine
