Make ecdf_line a step line

src/arviz_plots/backend/bokeh/__init__.py

@@ -354,6 +354,12 @@ def scatter(
     return target.scatter(np.atleast_1d(x), np.atleast_1d(y), **kwargs)
 
 
+def step(x, y, target, *, color=unset, alpha=unset, width=unset, linestyle=unset, **artist_kws):
+    """Interface to bokeh for a step line."""
+    kwargs = {"color": color, "alpha": alpha, "line_width": width, "line_dash": linestyle}
+    return target.step(np.atleast_1d(x), np.atleast_1d(y), **_filter_kwargs(kwargs, artist_kws))
+
+
 def text(
     x,
     y,

src/arviz_plots/backend/matplotlib/__init__.py

@@ -353,6 +353,13 @@ def scatter(
     return target.scatter(x, y, **_filter_kwargs(kwargs, None, artist_kws))
 
 
+def step(x, y, target, *, color=unset, alpha=unset, width=unset, linestyle=unset, **artist_kws):
+    """Interface to matplotlib for a step line."""
+    artist_kws.setdefault("zorder", 2)
+    kwargs = {"color": color, "alpha": alpha, "linewidth": width, "linestyle": linestyle}
+    return target.step(x, y, **_filter_kwargs(kwargs, Line2D, artist_kws))[0]
+
+
 def text(
     x,
     y,

src/arviz_plots/backend/none/__init__.py

@@ -281,6 +281,21 @@ def scatter(
     return artist_element
 
 
+def step(x, y, target, *, color=unset, alpha=unset, width=unset, linestyle=unset, **artist_kws):
+    """Interface to a step line."""
+    kwargs = {"color": color, "alpha": alpha, "width": width, "linestyle": linestyle}
+    if not ALLOW_KWARGS and artist_kws:
+        raise ValueError("artist_kws not empty")
+    artist_element = {
+        "function": "line",
+        "x": np.atleast_1d(x),
+        "y": np.atleast_1d(y),
+        **_filter_kwargs(kwargs, artist_kws),
+    }
+    target.append(artist_element)
+    return artist_element
+
+
 def text(
     x,
     y,

src/arviz_plots/backend/plotly/__init__.py

@@ -397,6 +397,23 @@ def scatter(
     return scatter_object
 
 
+def step(x, y, target, *, color=unset, alpha=unset, width=unset, linestyle=unset, **artist_kws):
+    """Interface to plotly for a step line."""
+    artist_kws.setdefault("showlegend", False)
+    line_kwargs = {"color": color, "width": width, "dash": linestyle}
+    line_artist_kws = artist_kws.pop("line", {"shape": "hv"}).copy()
+    kwargs = {"opacity": alpha}
+    line_object = go.Scatter(
+        x=np.atleast_1d(x),
+        y=np.atleast_1d(y),
+        mode="lines",
+        line=_filter_kwargs(line_kwargs, line_artist_kws),
+        **_filter_kwargs(kwargs, artist_kws),
+    )
+    target.add_trace(line_object)
+    return line_object
+
+
 def text(
     x,
     y,

src/arviz_plots/visuals/__init__.py

@@ -114,9 +114,9 @@ def scatter_xy(da, target, backend, x=None, y=None, **kwargs):
 
 
 def ecdf_line(values, target, backend, **kwargs):
-    """Plot an ecdf line."""
+    """Plot a step line."""
     plot_backend = import_module(f"arviz_plots.backend.{backend}")
-    return plot_backend.line(values.sel(plot_axis="x"), values.sel(plot_axis="y"), target, **kwargs)
+    return plot_backend.step(values.sel(plot_axis="x"), values.sel(plot_axis="y"), target, **kwargs)
 
 
 def vline(values, target, backend, **kwargs):