feat: Implement Altair version of grid visualization

mesa/experimental/components/altair.py

@@ -0,0 +1,60 @@
+import contextlib
+from typing import Optional
+
+import solara
+
+with contextlib.suppress(ImportError):
+    import altair as alt
+
+
+@solara.component
+def SpaceAltair(model, agent_portrayal, dependencies: Optional[list[any]] = None):
+    space = getattr(model, "grid", None)
+    if space is None:
+        # Sometimes the space is defined as model.space instead of model.grid
+        space = model.space
+    chart = _draw_grid(space, agent_portrayal)
+    solara.FigureAltair(chart)
+
+
+def _draw_grid(space, agent_portrayal):
+    def portray(g):
+        all_agent_data = []
+        for content, (x, y) in space.coord_iter():
+            if not content:
+                continue
+            if not hasattr(content, "__iter__"):
+                # Is a single grid
+                content = [content]  # noqa: PLW2901
+            for agent in content:
+                # use all data from agent portrayal, and add x,y coordinates
+                agent_data = agent_portrayal(agent)
+                agent_data["x"] = x
+                agent_data["y"] = y
+                all_agent_data.append(agent_data)
+        return all_agent_data
+
+    all_agent_data = portray(space)
+    encoding_dict = {
+        # no x-axis label
+        "x": alt.X("x", axis=None, type="ordinal"),
+        # no y-axis label
+        "y": alt.Y("y", axis=None, type="ordinal"),
+    }
+    has_color = "color" in all_agent_data[0]
+    if has_color:
+        encoding_dict["color"] = alt.Color("color", type="nominal")
+    has_size = "size" in all_agent_data[0]
+    if has_size:
+        encoding_dict["size"] = alt.Size("size", type="quantitative")
+
+    chart = (
+        alt.Chart(
+            alt.Data(values=all_agent_data), encoding=alt.Encoding(**encoding_dict)
+        )
+        .mark_point(filled=True)
+        .properties(width=280, height=280)
+        # .configure_view(strokeOpacity=0)  # hide grid/chart lines
+    )
+
+    return chart

mesa/experimental/jupyter_viz.py

@@ -6,6 +6,7 @@
 import solara
 from solara.alias import rv
 
+import mesa.experimental.components.altair as components_altair
 import mesa.experimental.components.matplotlib as components_matplotlib
 from mesa.experimental.UserParam import Slider
 
@@ -28,6 +29,10 @@ def Card(
                 components_matplotlib.SpaceMatplotlib(
                     model, agent_portrayal, dependencies=[current_step.value]
                 )
+            elif space_drawer == "altair":
+                components_altair.SpaceAltair(
+                    model, agent_portrayal, dependencies=[current_step.value]
+                )
             elif space_drawer:
                 # if specified, draw agent space with an alternate renderer
                 space_drawer(model, agent_portrayal)
@@ -113,6 +118,10 @@ def render_in_jupyter():
                 components_matplotlib.SpaceMatplotlib(
                     model, agent_portrayal, dependencies=[current_step.value]
                 )
+            elif space_drawer == "altair":
+                components_altair.SpaceAltair(
+                    model, agent_portrayal, dependencies=[current_step.value]
+                )
             elif space_drawer:
                 # if specified, draw agent space with an alternate renderer
                 space_drawer(model, agent_portrayal)