Reduce some dependencies.

baukit/plotwidget.py

@@ -1,5 +1,4 @@
 from .labwidget import Image, Property
-import matplotlib, matplotlib.pyplot
 import inspect
 
 class PlotWidget(Image):
@@ -25,10 +24,12 @@ class PlotWidget(Image):
     plot with freq set to 3.
     """
     def __init__(self, redraw_rule, rc=None, **kwargs):
+        import matplotlib, matplotlib.pyplot
         super().__init__()
         init_args = dict(kwargs)
-        render_args = dict(format='svg', figsize=(5, 3.5))
-        self.rc = {} if rc is None else rc
+        render_args = dict(format='svg')
+        if rc is None:
+            rc = {}
         
         all_names = []
         for i, (name, p) in enumerate(inspect.signature(redraw_rule).parameters.items()):
@@ -48,7 +49,11 @@ class PlotWidget(Image):
             if name in init_args:
                 render_args[name] = init_args.pop(name)
 
-        with matplotlib.pyplot.rc_context(rc=self.rc):
+        for default_arg, default_value in [('figsize', (5, 3.5))]:
+            if default_arg not in init_args:
+                init_args[default_arg] = default_value
+
+        with matplotlib.pyplot.rc_context(rc=rc):
             old_backend = matplotlib.pyplot.get_backend()
             matplotlib.pyplot.switch_backend('agg')
             if 'mosaic' in init_args:
@@ -58,7 +63,7 @@ class PlotWidget(Image):
         matplotlib.pyplot.switch_backend(old_backend)
 
         def invoke_redraw():
-            with matplotlib.pyplot.rc_context(rc=self.rc):
+            with matplotlib.pyplot.rc_context(rc=rc):
                 args = [self.fig]
                 for name in all_names:
                     args.append(getattr(self, name))

baukit/show.py

@@ -20,7 +20,6 @@ import base64
 import collections
 from contextlib import contextmanager
 import io
-import IPython
 import types
 import re
 import sys

notebooks/using_show_and_widgets.ipynb

@@ -339,7 +339,7 @@
    "id": "498e7872",
    "metadata": {},
    "source": [
-    "You can also respond to any property change using the `on()` method.  Here we trace whenever ra2 changes."
+    "You can also respond to any property change using the `on()` method.  Here we show a message whenever ra3 changes."
    ]
   },
   {
@@ -349,11 +349,16 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "def say_hello():\n",
-    "    print(f'ra3 is {ra3.value}')\n",
+    "from baukit import Div\n",
+    "\n",
+    "div = Div('change the slider')\n",
     "ra3 = Range()\n",
-    "ra3.on('value', say_hello)\n",
-    "show(ra3)"
+    "\n",
+    "def print_value():\n",
+    "    div.innerHTML = f'the value is {ra3.value}'\n",
+    "ra3.on('value', print_value)\n",
+    "\n",
+    "show([[div, show.style(flex=7), ra3]])"
    ]
   },
   {
@@ -383,14 +388,14 @@
     "def myplot(plt, frequency=1.0, amplitude=1.0):\n",
     "    [ax] = plt.axes\n",
     "    ax.clear()\n",
-    "    ax.set_title(f'Sine wave of frequency {frequency}, amplitude {amplitude}')\n",
+    "    ax.set_title(f'Sine wave of frequency {frequency:.2f}, amplitude {amplitude:.2f}')\n",
     "    x = torch.linspace(0, 20, 300)\n",
     "    y = (frequency * x).sin()\n",
     "    ax.plot(x, amplitude * y)\n",
     "    ax.set_ylim(-5, 5)\n",
     "\n",
-    "show([[PlotWidget(myplot, figsize=(5,3.5)),\n",
-    "       PlotWidget(myplot, frequency=2, amplitude=3, figsize=(5,3.5))]])"
+    "show([[PlotWidget(myplot),\n",
+    "       PlotWidget(myplot, frequency=2, amplitude=3)]])"
    ]
   },
   {