fix: DataFilterExtension get_filter_category

examples/!category_filter.ipynb

@@ -0,0 +1,183 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "9ffdeba2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# no intention of actually keeping this notebook in the repo, once it's all working good I'll make up a new doc about the category_filter\n",
+    "# I have added it for now to demonstrate that I've got the data filter filter_categories functionality working for numeric inputs\n",
+    "# looking at the deck gl docs: https://deck.gl/docs/api-reference/extensions/data-filter-extension#layer-properties\n",
+    "# it appears that we should be able to use strings for the categories but when I try to use string data the layer simply doesnt work\n",
+    "\n",
+    "import geopandas as gpd\n",
+    "import ipywidgets\n",
+    "import pyarrow as pa  # noqa\n",
+    "from shapely.geometry import Point\n",
+    "\n",
+    "import lonboard\n",
+    "from lonboard.basemap import CartoBasemap\n",
+    "from lonboard.layer_extension import DataFilterExtension\n",
+    "\n",
+    "cat_col = \"int_col\"\n",
+    "# int_col: works\n",
+    "# float_col: works\n",
+    "# str_col: does NOT work :(\n",
+    "#  as is it will throw an arro3 ValueError: Expected object with __arrow_c_array__ method or implementing buffer protocol.\n",
+    "#  we can avoid the arro3 exception by using pyarrow as the input to get_filter_category when we create the layer:\n",
+    "#    `get_filter_category=pa.array(gdf[cat_col])`\n",
+    "#  but the layer doesn't display and throws a lot of the following WebGL error:\n",
+    "#   GL_INVALID_OPERATION: Vertex shader input type does not match the type of the bound vertex attribute\n",
+    "\n",
+    "\n",
+    "d = {\n",
+    "    \"int_col\": [0, 1, 2, 3, 4, 5],\n",
+    "    \"float_col\": [0.0, 1.5, 0.0, 1.5, 0.0, 1.5],\n",
+    "    \"str_col\": [\"even\", \"odd\", \"even\", \"odd\", \"even\", \"odd\"],\n",
+    "    \"geometry\": [\n",
+    "        Point(0, 0),\n",
+    "        Point(1, 1),\n",
+    "        Point(2, 2),\n",
+    "        Point(3, 3),\n",
+    "        Point(4, 4),\n",
+    "        Point(5, 5),\n",
+    "    ],\n",
+    "}\n",
+    "gdf = gpd.GeoDataFrame(d, crs=\"EPSG:4326\")\n",
+    "\n",
+    "point_layer = lonboard.ScatterplotLayer.from_geopandas(\n",
+    "    gdf,\n",
+    "    get_fill_color=(0, 255, 0),\n",
+    "    radius_min_pixels=10,\n",
+    "    extensions=[\n",
+    "        DataFilterExtension(filter_size=None, category_size=1),\n",
+    "    ],  # no range filter, just a category\n",
+    "    get_filter_category=gdf[cat_col],  # use the cat column for the filter category\n",
+    ")\n",
+    "\n",
+    "m = lonboard.Map(layers=[point_layer], basemap_style=CartoBasemap.DarkMatter)\n",
+    "\n",
+    "filter_enabled_w = ipywidgets.Checkbox(\n",
+    "    value=True,\n",
+    "    description=\"Filter Enabled\",\n",
+    ")\n",
+    "\n",
+    "\n",
+    "def on_filter_enabled_change(change):  # noqa\n",
+    "    # when we change the checkbox, toggle filtering on the layer\n",
+    "    point_layer.filter_enabled = filter_enabled_w.value\n",
+    "\n",
+    "\n",
+    "filter_enabled_w.observe(on_filter_enabled_change, names=\"value\")\n",
+    "\n",
+    "cat_selector = ipywidgets.SelectMultiple(  # make a select multiple so we can see interaction on the map\n",
+    "    options=list(gdf[cat_col].unique()),\n",
+    "    value=[list(gdf[cat_col].unique())[0]],\n",
+    "    description=\"Category\",\n",
+    "    disabled=False,\n",
+    ")\n",
+    "\n",
+    "\n",
+    "def on_cat_selector_change(change) -> None:  # noqa\n",
+    "    # when we change the selector, update the filter on the layer.\n",
+    "    point_layer.filter_categories = cat_selector.value\n",
+    "\n",
+    "\n",
+    "cat_selector.observe(on_cat_selector_change, names=\"value\")\n",
+    "\n",
+    "ipywidgets.VBox([m, filter_enabled_w, cat_selector])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ce25544c",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "point_layer2 = lonboard.ScatterplotLayer.from_geopandas(\n",
+    "    gdf,\n",
+    "    get_fill_color=(0, 255, 0),\n",
+    "    radius_min_pixels=10,\n",
+    "    extensions=[\n",
+    "        DataFilterExtension(filter_size=1, category_size=None),\n",
+    "    ],  # no category filter, just a range\n",
+    "    get_filter_value=gdf[\"int_col\"],  # use the int_col for the filter category\n",
+    ")\n",
+    "\n",
+    "m2 = lonboard.Map(layers=[point_layer2], basemap_style=CartoBasemap.DarkMatter)\n",
+    "point_layer2.filter_range = [0, 5]\n",
+    "m2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ef71f006",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "point_layer2.filter_range = [1, 4]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "10e27c5d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "point_layer3 = lonboard.ScatterplotLayer.from_geopandas(\n",
+    "    gdf,\n",
+    "    get_fill_color=(0, 255, 0),\n",
+    "    radius_min_pixels=10,\n",
+    "    extensions=[\n",
+    "        DataFilterExtension(filter_size=1, category_size=1),\n",
+    "    ],  # no category filter, just a range\n",
+    "    get_filter_category=gdf[\n",
+    "        \"float_col\"\n",
+    "    ],  # use the float column for the filter category\n",
+    "    get_filter_value=gdf[\"int_col\"],  # use the int column for the filter category\n",
+    ")\n",
+    "\n",
+    "point_layer3.filter_categories = [1.5]\n",
+    "point_layer3.filter_range = [0, 3]\n",
+    "m3 = lonboard.Map(layers=[point_layer3], basemap_style=CartoBasemap.DarkMatter)\n",
+    "m3"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c3f48195",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "point_layer3.filter_range = [0, 5]"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "lonboard_category_filter",
+   "language": "python",
+   "name": "lonboard_category_filter"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.12.8"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

lonboard/layer_extension.py

@@ -5,6 +5,7 @@
 from lonboard._base import BaseExtension
 from lonboard.traits import (
     DashArrayAccessor,
+    FilterCategoryAccessor,
     FilterValueAccessor,
     FloatAccessor,
     PointAccessor,
@@ -353,15 +354,18 @@ class DataFilterExtension(BaseExtension):
         "filter_transform_size": t.Bool(default_value=True).tag(sync=True),
         "filter_transform_color": t.Bool(default_value=True).tag(sync=True),
         "get_filter_value": FilterValueAccessor(default_value=None, allow_none=True),
-        "get_filter_category": FilterValueAccessor(default_value=None, allow_none=True),
+        "get_filter_category": FilterCategoryAccessor(
+            default_value=None,
+            allow_none=True,
+        ),
     }
 
-    filter_size = t.Int(None, min=1, max=4, allow_none=True).tag(sync=True)
+    filter_size = t.Int(1, min=1, max=4, allow_none=True).tag(sync=True)
     """The size of the filter (number of columns to filter by).
 
     The data filter can show/hide data based on 1-4 numeric properties of each object.
 
-    - Type: `int`. This is required if using range-based filtering.
+    - Type: `int`, optional. This is required if using range-based filtering.
     - Default 1.
     """
 
@@ -370,8 +374,8 @@ class DataFilterExtension(BaseExtension):
 
     The category filter can show/hide data based on 1-4 properties of each object.
 
-    - Type: `int`. This is required if using category-based filtering.
-    - Default 0.
+    - Type: `int`, optional. This is required if using category-based filtering.
+    - Default None.
     """
 
 

lonboard/traits/__init__.py

@@ -7,7 +7,7 @@
 from ._a5 import A5Accessor
 from ._base import FixedErrorTraitType, VariableLengthTuple
 from ._color import ColorAccessor
-from ._extensions import DashArrayAccessor, FilterValueAccessor
+from ._extensions import DashArrayAccessor, FilterCategoryAccessor, FilterValueAccessor
 from ._float import FloatAccessor
 from ._h3 import H3Accessor
 from ._map import BasemapUrl, HeightTrait, ViewStateTrait
@@ -23,6 +23,7 @@
     "BasemapUrl",
     "ColorAccessor",
     "DashArrayAccessor",
+    "FilterCategoryAccessor",
     "FilterValueAccessor",
     "FixedErrorTraitType",
     "FloatAccessor",