Fix shape_example: migrate from ModularServer to SolaraViz (Mesa 3.x)

examples/charts/app.py

@@ -0,0 +1,60 @@
+import solara
+from charts.agents import Person
+from charts.model import Charts
+from mesa.visualization import SolaraViz, make_plot_component, make_space_component
+from mesa.visualization.components import AgentPortrayalStyle
+from mesa.visualization.user_param import Slider
+
+# Colors - same palette as the original server.py (Matplotlib tab10)
+RICH_COLOR = "#2ca02c"  # green
+POOR_COLOR = "#d62728"  # red
+MID_COLOR = "#1f77b4"  # blue
+
+
+def agent_portrayal(agent):
+    """
+    Returns AgentPortrayalStyle (Mesa 3.x) instead of a dict.
+    Color encodes wealth class:
+      green -> savings > rich_threshold  (rich)
+      red   -> loans > 10               (poor)
+      blue  -> everything else          (middle class)
+    """
+    if not isinstance(agent, Person):
+        return AgentPortrayalStyle()
+
+    color = MID_COLOR
+
+    if agent.savings > agent.model.rich_threshold:
+        color = RICH_COLOR
+    if agent.loans > 10:
+        color = POOR_COLOR
+
+    return AgentPortrayalStyle(color=color, size=20, marker="o")
+
+
+model_params = {
+    "init_people": Slider(label="People", value=25, min=1, max=200, step=1),
+    "rich_threshold": Slider(label="Rich Threshold", value=10, min=1, max=20, step=1),
+    "reserve_percent": Slider(label="Reserves (%)", value=50, min=1, max=100, step=1),
+}
+
+SpaceGraph = make_space_component(agent_portrayal)
+
+WealthClassChart = make_plot_component(
+    {"Rich": RICH_COLOR, "Poor": POOR_COLOR, "Middle Class": MID_COLOR}
+)
+
+MoneySupplyChart = make_plot_component(
+    {"Savings": "#9467bd", "Wallets": "#8c564b", "Money": "#17becf", "Loans": "#e377c2"}
+)
+
+# Wrap the instance in solara.Reactive to prevent render loops.
+# SolaraViz expects Model | solara.Reactive[Model].
+model = solara.Reactive(Charts())
+
+page = SolaraViz(
+    model,
+    components=[SpaceGraph, WealthClassChart, MoneySupplyChart],
+    model_params=model_params,
+    name="Mesa Charts - Bank Reserves",
+)

examples/charts/run.py

@@ -1,3 +1,6 @@
-from charts.server import server
+import subprocess
+import sys
+from pathlib import Path
 
-server.launch(open_browser=True)
+app_path = Path(__file__).parent / "app.py"
+subprocess.run([sys.executable, "-m", "solara", "run", str(app_path)], check=False)

examples/hex_ant/app.py

@@ -1,10 +1,9 @@
 import matplotlib.pyplot as plt
+from agent import AntState
 from matplotlib.colors import LinearSegmentedColormap, ListedColormap
 from mesa.visualization import SolaraViz, make_space_component
 from mesa.visualization.components import PropertyLayerStyle
-
-from .agent import AntState
-from .model import AntForaging
+from model import AntForaging
 
 plt.rcParams["figure.figsize"] = (10, 10)
 

examples/hex_ant/model.py

@@ -1,8 +1,7 @@
 import mesa
+from agent import Ant
 from mesa.discrete_space import HexGrid
 
-from .agent import Ant
-
 
 class AntForaging(mesa.Model):
     """

examples/hex_snowflake/hex_snowflake/app.py

@@ -0,0 +1,21 @@
+from hex_snowflake.cell import Cell
+from hex_snowflake.model import HexSnowflake
+from mesa.visualization import SolaraViz, make_space_component
+
+
+def agent_portrayal(agent):
+    if agent is None:
+        return
+
+    if isinstance(agent, Cell):
+        color = "tab:green" if agent.state == Cell.ALIVE else "tab:grey"
+        return {"color": color, "size": 20}
+
+
+model = HexSnowflake()
+
+page = SolaraViz(
+    model,
+    components=[make_space_component(agent_portrayal=agent_portrayal)],
+    name="Hex Snowflake",
+)

examples/hex_snowflake/run.py

@@ -1,3 +0,0 @@
-from hex_snowflake.server import server
-
-server.launch(open_browser=True)

examples/shape_example/run.py

@@ -1,3 +0,0 @@
-from shape_example.server import server
-
-server.launch(open_browser=True)

examples/shape_example/shape_example/app.py

@@ -0,0 +1,20 @@
+from mesa.visualization import SolaraViz, make_space_component
+from shape_example.model import ShapeExample, Walker
+
+
+def agent_portrayal(agent):
+    if isinstance(agent, Walker):
+        return {
+            "color": "tab:green",
+            "size": 50,
+            "marker": "^",
+        }
+
+
+model = ShapeExample()
+
+page = SolaraViz(
+    model,
+    components=[make_space_component(agent_portrayal=agent_portrayal)],
+    name="Shape Model Example",
+)

examples/shape_example/shape_example/model.py

@@ -1,34 +1,35 @@
 import mesa
-from mesa.discrete_space import OrthogonalMooreGrid
+from mesa.discrete_space import CellAgent, OrthogonalMooreGrid
 
 
-class Walker(mesa.Agent):
+class Walker(CellAgent):  # ← CellAgent not mesa.Agent
     def __init__(self, model, heading=(1, 0)):
         super().__init__(model)
         self.heading = heading
-        self.headings = {(1, 0), (0, 1), (-1, 0), (0, -1)}
+        self.headings = ((1, 0), (0, 1), (-1, 0), (0, -1))
+
+    def step(self):
+        new_cell = self.random.choice(list(self.cell.neighborhood))
+        if new_cell.is_empty:
+            self.cell = new_cell
+        self.heading = self.random.choice(self.headings)
 
 
 class ShapeExample(mesa.Model):
-    def __init__(self, num_agents=2, width=20, height=10):
+    def __init__(self, num_agents=5, width=20, height=10):
         super().__init__()
-        self.num_agents = num_agents  # num of agents
-        self.headings = ((1, 0), (0, 1), (-1, 0), (0, -1))  # tuples are fast
+        self.num_agents = num_agents
+        self.headings = ((1, 0), (0, 1), (-1, 0), (0, -1))
         self.grid = OrthogonalMooreGrid((width, height), torus=True, random=self.random)
-
         self.make_walker_agents()
         self.running = True
 
     def make_walker_agents(self):
-        for _ in range(self.num_agents):
-            x = self.random.randrange(self.grid.dimensions[0])
-            y = self.random.randrange(self.grid.dimensions[1])
-            cell = self.grid[(x, y)]
+        cells = self.random.sample(list(self.grid.all_cells), self.num_agents)
+        for cell in cells:
             heading = self.random.choice(self.headings)
-            # heading = (1, 0)
-            if cell.is_empty:
-                a = Walker(self, heading)
-                a.cell = cell
+            a = Walker(self, heading)
+            a.cell = cell
 
     def step(self):
         self.agents.shuffle_do("step")