Adding dropdown menu to image segmentation tool example

examples/image-segmentation.ipynb

@@ -145,6 +145,46 @@
     "plt.imshow(multi_class_segmenter.mask)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Integration with ipywidgets\n",
+    "\n",
+    "To reduce friction in the labelling workflow you can construct controls for the currently selected class and whether to be in erasing mode using ipywidgets."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import ipywidgets as widgets\n",
+    "\n",
+    "N_classes = 3\n",
+    "class_selector = widgets.Dropdown(options=list(range(1, N_classes + 1)), description=\"class\")\n",
+    "\n",
+    "def update(change):\n",
+    "    multi_class_segmenter.current_class = class_selector.value\n",
+    "    multi_class_segmenter.erasing = erasing_button.value\n",
+    "\n",
+    "erasing_button = widgets.Checkbox(value=False, description=\"Erasing\")\n",
+    "erasing_button.observe(update, names=\"value\")\n",
+    "\n",
+    "class_selector.observe(update, names=\"value\")\n",
+    "multi_class_segmenter = image_segmenter(image, nclasses=3, mask_alpha=0.76)\n",
+    "display(widgets.HBox([erasing_button, class_selector]))\n",
+    "display(multi_class_segmenter)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -241,7 +281,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.5"
+   "version": "3.9.1"
   }
  },
  "nbformat": 4,

mpl_interactions/tests/test_controls.py

@@ -12,5 +12,11 @@ def cb(**kwargs):
     assert len(zoop) == 1
 
     ctrls = Controls(beep=(0, 1), boop=(0, 1))
-    ctrls.register_callback(cb, "beep", eager=True)
+    ctrls.register_callback(cb, "beep", eager=False)
     assert len(zoop) == 1
+
+    ctrls.controls["beep"].set_val(0.5)
+    assert len(zoop) == 2
+
+    ctrls.controls["boop"].set_val(0.5)
+    assert len(zoop) == 2