Add support for interactive mode on Matplotlib (#1469)

* Add support for interactive mode on Matplotlib

* Minor fixes

* Add ipympl

* Fix for pn.ipywidget

examples/reference/panes/Matplotlib.ipynb

@@ -20,6 +20,7 @@
     "#### Parameters:\n",
     "\n",
     "* **``dpi``** (int, default=144): The dots per inch of the exported png\n",
+    "* **``interactive``** (boolean, default=False): Whether to use the interactive ipympl backend\n",
     "* **``tight``** (bool, default=False): Automatically adjust the figure size to fit the subplots and other artist elements.\n",
     "* **``object``** (matplotlib.Figure): The Matplotlib Figure object to display\n",
     "\n",
@@ -111,7 +112,23 @@
     "ax.set_zlabel('Z')\n",
     "ax.set_zlim(-100, 100)\n",
     "\n",
-    "mpl_pane.object= fig"
+    "mpl_pane.object = fig"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "If you have installed `ipympl` you will also be able to use the `interactive` backend:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "pn.pane.Matplotlib(fig, interactive=True, dpi=72)"
    ]
   },
   {

panel/io/notebook.py

@@ -318,7 +318,7 @@ def ipywidget(obj, **kwargs):
     from jupyter_bokeh import BokehModel
     from ..pane import panel
     model = panel(obj, **kwargs).get_root()
-    widget = BokehModel(model)
+    widget = BokehModel(model, combine_events=True)
     if hasattr(widget, '_view_count'):
         widget._view_count = 0
         def view_count_changed(change, current=[model]):

panel/pane/ace.py

@@ -63,5 +63,5 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         self._models[root.ref['id']] = (model, parent)
         return model
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         model.code = self.object if self.object else ''

panel/pane/base.py

@@ -151,7 +151,7 @@ def _init_properties(self):
     def _update_object(self, ref, doc, root, parent, comm):
         old_model = self._models[ref][0]
         if self._updates:
-            self._update(old_model)
+            self._update(ref, old_model)
         else:
             new_model = self._get_model(doc, root, parent, comm)
             try:
@@ -196,7 +196,7 @@ def _update_pane(self, *events):
                 else:
                     cb()
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         """
         If _updates=True this method is used to update an existing
         Bokeh model instead of replacing the model entirely. The

panel/pane/deckgl.py

@@ -212,7 +212,7 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         self._models[root.ref["id"]] = (model, parent)
         return model
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         data, properties = self._get_properties(layout=False)
         self._update_sources(data, model.data_sources)
         properties['data'] = data

panel/pane/ipywidget.py

@@ -15,25 +15,28 @@ class IPyWidget(PaneBase):
     def applies(cls, obj):
         return (hasattr(obj, 'traits') and hasattr(obj, 'get_manager_state') and hasattr(obj, 'comm'))
 
-    def _get_model(self, doc, root=None, parent=None, comm=None):
-        if root is None:
-            return self._get_root(doc, comm)
-
+    def _get_ipywidget(self, obj, doc, root, comm, **kwargs):
         if isinstance(comm, JupyterComm) and not config.embed:
             IPyWidget = _BkIPyWidget
         else:
             import ipykernel
-            from ipywidgets_bokeh.widget import IPyWidget
             from ipywidgets_bokeh.kernel import BokehKernel
+            from ipywidgets_bokeh.widget import IPyWidget
             if not isinstance(ipykernel.kernelbase.Kernel._instance, BokehKernel):
                 from ..io.ipywidget import PanelKernel
-                kernel = PanelKernel(key=root.ref['id'].encode('utf-8'), document=doc)
-                for w in self.object.widgets.values():
+                kernel = PanelKernel(document=doc, key=str(id(doc)).encode('utf-8'))
+                for w in obj.widgets.values():
                     w.comm.kernel = kernel
                     w.comm.open()
 
-        props = self._process_param_change(self._init_properties())
-        model = IPyWidget(widget=self.object, **props)
+        model = IPyWidget(widget=obj, **kwargs)
+        return model
+
+    def _get_model(self, doc, root=None, parent=None, comm=None):
+        if root is None:
+            return self.get_root(doc, comm)
+        kwargs = self._process_param_change(self._init_properties())
+        model = self._get_ipywidget(self.object, doc, root, comm, **kwargs)
         self._models[root.ref['id']] = (model, parent)
         return model
 

panel/pane/markup.py

@@ -46,7 +46,7 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         self._models[root.ref['id']] = (model, parent)
         return model
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         model.update(**self._get_properties())
 
 

panel/pane/plot.py

@@ -17,6 +17,7 @@
 from ..io.notebook import push
 from ..viewable import Layoutable
 from .base import PaneBase
+from .ipywidget import IPyWidget
 from .markup import HTML
 from .image import PNG
 
@@ -113,7 +114,7 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         return model
 
 
-class Matplotlib(PNG):
+class Matplotlib(PNG, IPyWidget):
     """
     A Matplotlib pane renders a matplotlib figure to png and wraps the
     base64 encoded data in a bokeh Div model. The size of the image in
@@ -125,6 +126,9 @@ class Matplotlib(PNG):
     dpi = param.Integer(default=144, bounds=(1, None), doc="""
         Scales the dpi of the matplotlib figure.""")
 
+    interactive = param.Boolean(default=False, constant=True, doc="""
+    """)
+
     tight = param.Boolean(default=False, doc="""
         Automatically adjust the figure size to fit the
         subplots and other artist elements.""")
@@ -142,6 +146,63 @@ def applies(cls, obj):
                              'cannot be rendered.')
         return is_fig
 
+    def __init__(self, object=None, **params):
+        super(Matplotlib, self).__init__(object, **params)
+        self._managers = {}
+
+    def _get_widget(self, fig):
+        import matplotlib
+        old_backend = getattr(matplotlib.backends, 'backend', 'agg')
+
+        from ipympl.backend_nbagg import FigureManager, Canvas, is_interactive
+        from matplotlib._pylab_helpers import Gcf
+
+        matplotlib.use(old_backend)
+
+        def closer(event):
+            Gcf.destroy(0)
+
+        canvas = Canvas(fig)
+        fig.patch.set_alpha(0)
+        manager = FigureManager(canvas, 0)
+
+        if is_interactive():
+            fig.canvas.draw_idle()
+
+        canvas.mpl_connect('close_event', closer)
+        return manager
+
+    def _get_model(self, doc, root=None, parent=None, comm=None):
+        if not self.interactive:
+            return PNG._get_model(self, doc, root, parent, comm)
+        self.object.set_dpi(self.dpi)
+        manager = self._get_widget(self.object)
+        props = self._process_param_change(self._init_properties())
+        kwargs = {k: v for k, v in props.items()
+                  if k not in self._rerender_params+['interactive']}
+        model = self._get_ipywidget(manager.canvas, doc, root, comm,
+                                    **kwargs)
+        if root is None:
+            root = model
+        self._models[root.ref['id']] = (model, parent)
+        self._managers[root.ref['id']] = manager
+        return model
+
+    def _update(self, ref=None, model=None):
+        if not self.interactive:
+            model.update(**self._get_properties())
+            return
+        manager = self._managers[ref]
+        if self.object is not manager.canvas.figure:
+            self.object.set_dpi(self.dpi)
+            self.object.patch.set_alpha(0)
+            manager.canvas.figure = self.object
+            self.object.set_canvas(manager.canvas)
+            event = {'width': manager.canvas._width,
+                     'height': manager.canvas._height}
+            manager.canvas.handle_resize(event)
+        manager.canvas.draw_idle()
+
     def _imgshape(self, data):
         """Calculate and return image width,height"""
         w, h = self.object.get_size_inches()

panel/pane/plotly.py

@@ -237,7 +237,7 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         self._models[root.ref['id']] = (model, parent)
         return model
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         if self.object is None:
             model.update(data=[], layout={})
             model._render_count += 1

panel/pane/vega.py

@@ -162,7 +162,7 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         self._models[root.ref['id']] = (model, parent)
         return model
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         if self.object is None:
             json = None
         else:

panel/pane/vtk/vtk.py

@@ -365,7 +365,7 @@ def __init__(self, object=None, **params):
         super(VTKRenderWindow, self).__init__(object, **params)
         if object is not None:
             self.color_mappers = self.get_color_mappers()
-            self._update(model=None)
+            self._update()
 
     def _get_model(self, doc, root=None, parent=None, comm=None):
         VTKSynchronizedPlot = super(VTKRenderWindow, self)._get_model(doc, root=None, parent=None, comm=None)
@@ -383,7 +383,7 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         self._models[root.ref['id']] = (model, parent)
         return model
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         import panel.pane.vtk.synchronizable_serializer as rws
         context = rws.SynchronizationContext(id_root=make_globally_unique_id(), debug=self._debug_serializer)
         self._scene, self._arrays = self._serialize_ren_win(
@@ -450,7 +450,7 @@ def _cleanup(self, root):
         self._contexts.pop(ref, None)
         super(VTKRenderWindowSynchronized, self)._cleanup(root)
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         context = self._contexts[model.id]
         scene, arrays = self._serialize_ren_win(
             self.object, 
@@ -670,7 +670,7 @@ def _process_property_change(self, msg):
                     msg[k] = int(np.round(v * ori_dim[index] / sub_dim[index]))
         return msg
 
-    def _update(self, model=None):
+    def _update(self, ref=None, model=None):
         self._volume_data = self._get_volume_data()
         if self._volume_data is not None:
             self._orginal_dimensions = self._get_object_dimensions()
@@ -814,7 +814,7 @@ def _get_vtkjs(self):
             self._vtkjs = vtkjs
         return self._vtkjs
 
-    def _update(self, model):
+    def _update(self, ref=None, model=None):
         self._vtkjs = None
         vtkjs = self._get_vtkjs()
         model.data = base64encode(vtkjs) if vtkjs is not None else vtkjs

setup.py

@@ -114,6 +114,7 @@ def run(self):
     'pytest-cov',
     'codecov',
     'folium',
+    'ipympl'
 ]
 
 extras_require = {