From f4d12546b4deefab4778a3238e037b37f4198133 Mon Sep 17 00:00:00 2001
From: Michael Waskom <mwaskom@gmail.com>
Date: Wed, 5 Oct 2022 06:58:35 -0400
Subject: [PATCH] Add example for Band and update release notes

---
 doc/_docstrings/objects.Band.ipynb | 30 +++++++++++++++++++++++++++---
 doc/whatsnew/v0.12.1.rst           |  2 ++
 seaborn/_marks/area.py             |  2 +-
 seaborn/_marks/line.py             |  2 +-
 4 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/doc/_docstrings/objects.Band.ipynb b/doc/_docstrings/objects.Band.ipynb
index 5419a1935d..bcd1975847 100644
--- a/doc/_docstrings/objects.Band.ipynb
+++ b/doc/_docstrings/objects.Band.ipynb
@@ -13,7 +13,7 @@
    "source": [
     "import seaborn.objects as so\n",
     "from seaborn import load_dataset\n",
-    "fmri = load_dataset(\"fmri\")\n",
+    "fmri = load_dataset(\"fmri\").query(\"region == 'parietal'\")\n",
     "seaice = (\n",
     "    load_dataset(\"seaice\")\n",
     "    .assign(\n",
@@ -22,7 +22,7 @@
     "    )\n",
     "    .query(\"Year >= 1980\")\n",
     "    .astype({\"Year\": str})\n",
-    "    .pivot(\"Day\", \"Year\", \"Extent\")\n",
+    "    .pivot(index=\"Day\", columns=\"Year\", values=\"Extent\")\n",
     "    .filter([\"1980\", \"2019\"])\n",
     "    .dropna()\n",
     "    .reset_index()\n",
@@ -90,8 +90,32 @@
   },
   {
    "cell_type": "raw",
-   "id": "4e817cdd-09a3-4cf6-8602-e9665607bfe1",
+   "id": "9f0c82bf-3457-4ac5-ba48-8930bac03d75",
    "metadata": {},
+   "source": [
+    "When min/max values are not explicitly assigned or added in a transform, the band will cover the full extent of the data:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "309f578e-da3d-4dc5-b6ac-a354321334c8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "(\n",
+    "    so.Plot(fmri, x=\"timepoint\", y=\"signal\", color=\"event\")\n",
+    "    .add(so.Line(linewidth=.5), group=\"subject\")\n",
+    "    .add(so.Band())\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "4330a3cd-63fe-470a-8e83-09e9606643b5",
+   "metadata": {},
+   "outputs": [],
    "source": []
   }
  ],
diff --git a/doc/whatsnew/v0.12.1.rst b/doc/whatsnew/v0.12.1.rst
index 6fe496f19b..a1ea32926c 100644
--- a/doc/whatsnew/v0.12.1.rst
+++ b/doc/whatsnew/v0.12.1.rst
@@ -4,6 +4,8 @@ v0.12.1 (Unreleased)
 
 - |Feature| Added the :class:`objects.Text` mark (:pr:`3051`).
 
+- |Feature| The :class:`Band` and :class:`Range` marks will now cover the full extent of the data if `min` / `max` variables are not explicitly assigned or added in a transform (:pr:`3056`).
+
 - |Fix| Make :class:`objects.PolyFit` robust to missing data (:pr:`3010`).
 
 - |Fix| Fixed a bug that caused an exception when more than two layers with the same mappings were added (:pr:`3055`).
diff --git a/seaborn/_marks/area.py b/seaborn/_marks/area.py
index 373f8234a4..b3602ad7e6 100644
--- a/seaborn/_marks/area.py
+++ b/seaborn/_marks/area.py
@@ -166,5 +166,5 @@ def _standardize_coordinate_parameters(self, data, orient):
         other = {"x": "y", "y": "x"}[orient]
         if not set(data.columns) & {f"{other}min", f"{other}max"}:
             agg = {f"{other}min": (other, "min"), f"{other}max": (other, "max")}
-            data = data.groupby(orient, as_index=False).agg(**agg)
+            data = data.groupby(orient).agg(**agg).reset_index()
         return data
diff --git a/seaborn/_marks/line.py b/seaborn/_marks/line.py
index 85bbffb15b..aa83fdaacf 100644
--- a/seaborn/_marks/line.py
+++ b/seaborn/_marks/line.py
@@ -279,7 +279,7 @@ def _setup_lines(self, split_gen, scales, orient):
             # TODO what if only one exist?
             if not set(data.columns) & {f"{other}min", f"{other}max"}:
                 agg = {f"{other}min": (other, "min"), f"{other}max": (other, "max")}
-                data = data.groupby(orient, as_index=False).agg(**agg)
+                data = data.groupby(orient).agg(**agg).reset_index()
 
             cols = [orient, f"{other}min", f"{other}max"]
             data = data[cols].melt(orient, value_name=other)[["x", "y"]]