update with details on shapes in legends

Author: LiamConnors

doc/python/legend.md

@@ -6,7 +6,7 @@ jupyter:
       extension: .md
       format_name: markdown
       format_version: '1.3'
-      jupytext_version: 1.14.6
+      jupytext_version: 1.14.7
   kernelspec:
     display_name: Python 3 (ipykernel)
     language: python
@@ -20,7 +20,7 @@ jupyter:
     name: python
     nbconvert_exporter: python
     pygments_lexer: ipython3
-    version: 3.10.11
+    version: 3.10.4
   plotly:
     description: How to configure and style the legend in Plotly with Python.
     display_as: file_settings
@@ -35,7 +35,7 @@ jupyter:
 
 ### Trace Types, Legends and Color Bars
 
-[Traces](/python/figure-structure) of most types can be optionally associated with a single legend item in the [legend](/python/legend/). Whether or not a given trace appears in the legend is controlled via the `showlegend` attribute. Traces which are their own subplots (see above) do not support this, with the exception of traces of type `pie` and `funnelarea` for which every distinct color represented in the trace gets a separate legend item. Users may show or hide traces by clicking or double-clicking on their associated legend item. Traces that support legend items also support the `legendgroup` attribute, and all traces with the same legend group are treated the same way during click/double-click interactions.
+[Traces](/python/figure-structure) of most types and shapes can be optionally associated with a single legend item in the [legend](/python/legend/). Whether or not a given trace or shape appears in the legend is controlled via the `showlegend` attribute. Traces which are their own subplots (see above) do not support this, with the exception of traces of type `pie` and `funnelarea` for which every distinct color represented in the trace gets a separate legend item. Users may show or hide traces by clicking or double-clicking on their associated legend item. Traces that support legend items and shapes also support the `legendgroup` attribute, and all traces and shapes with the same legend group are treated the same way during click/double-click interactions.
 
 The fact that legend items are linked to traces means that when using [discrete color](/python/discrete-color/), a figure must have one trace per color in order to get a meaningful legend. [Plotly Express has robust support for discrete color](/python/discrete-color/) to make this easy.
 
@@ -97,26 +97,66 @@ fig.add_trace(go.Bar(name="fourth", x=["a", "b"], y=[2,1]))
 fig.show()
 ```
 
-*New in v5.0*
+*New in 5.16*
 
-The `legendrank` attribute of a trace can be used to control its placement within the legend, without regard for its placement in the `data` list.
+If you have shapes that appear in a legend, these are displayed after all traces:
 
-The default `legendrank` for traces is 1000 and ties are broken as described above, meaning that any trace can be pulled up to the top if it is the only one with a legend rank less than 1000 and pushed to the bottom if it is the only one with a rank greater than 1000.
+```python
+import plotly.graph_objects as go
+
+fig = go.Figure()
+fig.add_trace(go.Bar(name="first", x=["a", "b"], y=[1, 2]))
+fig.add_trace(go.Bar(name="second", x=["a", "b"], y=[2, 1]))
+fig.add_shape(
+    name="first shape",
+    showlegend=True,
+    type="rect",
+    xref="paper",
+    line=dict(dash="dash"),
+    x0=0.85,
+    x1=0.95,
+    y0=0,
+    y1=1.5,
+)
+fig.add_trace(go.Bar(name="third", x=["a", "b"], y=[1, 2]))
+fig.add_trace(go.Bar(name="fourth", x=["a", "b"], y=[2, 1]))
+v
+fig.show()
+
+```
+
+The `legendrank` attribute of a trace or shape can be used to control its placement in the legend.
+The default `legendrank` for traces and shapes is 1000. When all traces and shapes have the same `legendrank`, traces appear in the order they appear in the data, followed by shapes in the order they are defined. 
+
+Any trace or shape can be pulled up to the top of the legend if it is the only one with a legend rank less than 1000 and pushed to the bottom if it is the only one with a rank greater than 1000.
+
+In this example, we add a `legendrank` for each trace and shape, giving the shape the lowest rank so it appears first, and moving the first trace defined to the bottom of the legend by giving it the highest rank.
 
 ```python
 import plotly.graph_objects as go
 
 fig = go.Figure()
-fig.add_trace(go.Bar(name="fourth", x=["a", "b"], y=[2,1], legendrank=4))
-fig.add_trace(go.Bar(name="second", x=["a", "b"], y=[2,1], legendrank=2))
-fig.add_trace(go.Bar(name="first", x=["a", "b"], y=[1,2], legendrank=1))
+fig.add_trace(go.Bar(name="fourth", x=["a", "b"], y=[2,1], legendrank=5))
+fig.add_trace(go.Bar(name="second", x=["a", "b"], y=[2,1], legendrank=4))
+fig.add_trace(go.Bar(name="first", x=["a", "b"], y=[1,2], legendrank=2))
 fig.add_trace(go.Bar(name="third", x=["a", "b"], y=[1,2], legendrank=3))
+fig.add_shape(
+    legendrank=1,
+    showlegend=True,
+    type="line",
+    xref="paper",
+    line=dict(dash="5px"),
+    x0=0.05,
+    x1=0.45,
+    y0=1.5,
+    y1=1.5,
+)
 fig.show()
 ```
 
 #### Showing and Hiding the Legend
 
-By default the legend is displayed on Plotly charts with multiple traces, and this can be explicitly set with the `layout.showlegend` attribute:
+By default the legend is displayed on Plotly charts with multiple traces, and this can be explicitly set with the `layout.showlegend` attribute.
 
 ```python
 import plotly.express as px
@@ -193,7 +233,7 @@ fig.show()
 
 *New in 5.11*
 
-Set the width of horizontal legend entries by setting `entrywidth`. Here we set it to `70` pixels. Pixels is the default unit for `entrywidth`, but you can set it to be a fraction of the plot width using `entrywidthmode='fraction`.
+Set the width of horizontal legend entries by setting `entrywidth`. Here we set it to `70` pixels. Pixels is the default unit for `entrywidth`, but you can set it to be a fraction of the plot width using `entrywidthmode='fraction'`.
 
 ```python
 import plotly.express as px
@@ -253,7 +293,7 @@ When creating figures using [graph objects](/python/graph-objects/) without usin
 
 #### Legend Item Names
 
-Legend items appear per trace, and the legend item name is taken from the trace's `name` attribute.
+For traces, legend items appear per trace, and the legend item name is taken from the trace's `name` attribute.
 
 ```python
 import plotly.graph_objects as go
@@ -275,6 +315,38 @@ fig.add_trace(go.Scatter(
 fig.show()
 ```
 
+By default, for shapes, legend items are disabled. Set `showlegend=True` on a shape for it to dislay a legend item.
+The name that appears for the shape in the legend is the shape's `name` if it is provided. If no `name` is provided, the shape label's `text` is used. If neither is provided, the legend item appears as "shape \<shape number>". For example, "shape 1".
+
+```python
+import plotly.graph_objects as go
+
+fig = go.Figure()
+
+fig.add_trace(go.Scatter(
+    x=[1, 2, 3, 4, 5],
+    y=[1, 2, 3, 4, 5],
+    name="Positive"
+))
+
+fig.add_trace(go.Scatter(
+    x=[1, 2, 3, 4, 5],
+    y=[5, 4, 3, 2, 1],
+    name="Negative"
+))
+
+fig.add_shape(
+    showlegend=True,
+    type="rect",
+    x0=2,
+    x1=4,
+    y0=4.5,
+    y1=5,
+)
+
+fig.show()
+```
+
 #### Legend titles
 
 ```python
@@ -324,7 +396,7 @@ fig.show()
 
 #### Hiding the Trace Initially
 
-Traces have a `visible` attribute. If set to `legendonly`, the trace is hidden from the graph implicitly. Click on the name in the legend to display the hidden trace.
+Traces and shapes have a `visible` attribute. If set to `legendonly`, the trace or shape is hidden from the graph implicitly. Click on the name in the legend to display the hidden trace or shape.
 
 ```python
 import plotly.graph_objects as go
@@ -578,7 +650,7 @@ fig.show()
 
 *New in 5.15*
 
-By default, all traces appear on one legend. To have multiple legends, specify an alternative legend for a trace using the `legend` property. For a second legend, set `legend="legend2"`. Specify more legends with `legend="legend3"`, `legend="legend4"` and so on.
+By default, all traces and shapes appear on one legend. To have multiple legends, specify an alternative legend for a trace or shape using the `legend` property. For a second legend, set `legend="legend2"`. Specify more legends with `legend="legend3"`, `legend="legend4"` and so on.
 
 In this example, the last two scatter traces display on the second legend, "legend2". On the figure's layout, we then position and style each legend.