feat(plotnine): implement rose-basic (#5600)

## Implementation: `rose-basic` - python/plotnine

Implements the **python/plotnine** version of `rose-basic`.

**File:** `plots/rose-basic/implementations/python/plotnine.py`

**Parent Issue:** #1003

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/25151963204)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Markus Neusinger <2921697+MarkusNeusinger@users.noreply.github.com>

Author: github-actions[bot]

plots/rose-basic/implementations/python/plotnine.py

@@ -1,16 +1,27 @@
-""" pyplots.ai
+""" anyplot.ai
 rose-basic: Basic Rose Chart
-Library: plotnine 0.15.2 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-23
+Library: plotnine 0.15.3 | Python 3.13.13
+Quality: 85/100 | Updated: 2026-04-30
 """
 
 import math
+import os
+import sys
+
+
+# Remove this file's own directory from sys.path so that "plotnine" resolves
+# to the installed library rather than this file (Python 3.13 naming-collision fix).
+_script_dir = os.path.dirname(os.path.abspath(__file__))
+sys.path = [p for p in sys.path if os.path.realpath(p) != os.path.realpath(_script_dir)]
 
 import numpy as np
 import pandas as pd
+from matplotlib import colormaps
+from matplotlib.colors import Normalize, to_hex
 from plotnine import (
     aes,
     element_blank,
+    element_rect,
     element_text,
     geom_line,
     geom_polygon,
@@ -24,133 +35,97 @@
 )
 
 
+# Theme tokens
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
+INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
+
 # Data - Monthly rainfall (mm) for a temperate climate
 months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
 rainfall = [78, 62, 55, 48, 52, 68, 82, 85, 72, 88, 95, 82]
 
 n = len(months)
 
+# Viridis colors per month based on rainfall value (continuous colormap for value-encoded data)
+_norm = Normalize(vmin=min(rainfall), vmax=max(rainfall))
+_cmap = colormaps["viridis"]
+month_colors = {month: to_hex(_cmap(_norm(val))) for month, val in zip(months, rainfall, strict=True)}
+
 # Create wedge polygons for each month
-# Each wedge is a triangle from center to the arc
+n_arc_points = 30
 wedge_rows = []
-n_arc_points = 30  # Points along the arc for smooth edges
-
 for i, (month, value) in enumerate(zip(months, rainfall, strict=True)):
-    # Starting angle (12 o'clock = pi/2, going clockwise)
-    # Adjust so January is at top (index 0 starts at pi/2)
-    # Use negative direction for clockwise motion
     start_angle = math.pi / 2 - (i * 2 * math.pi / n)
     end_angle = math.pi / 2 - ((i + 1) * 2 * math.pi / n)
-
-    # Small gap between wedges
     gap = 0.02
     start_angle += gap
     end_angle -= gap
-
-    # Center point
     wedge_rows.append({"x": 0, "y": 0, "month": month, "order": 0})
-
-    # Arc points
-    arc_angles = np.linspace(start_angle, end_angle, n_arc_points)
-    for j, angle in enumerate(arc_angles):
-        x = value * math.cos(angle)
-        y = value * math.sin(angle)
-        wedge_rows.append({"x": x, "y": y, "month": month, "order": j + 1})
-
-    # Close back to center
+    for j, angle in enumerate(np.linspace(start_angle, end_angle, n_arc_points)):
+        wedge_rows.append({"x": value * math.cos(angle), "y": value * math.sin(angle), "month": month, "order": j + 1})
     wedge_rows.append({"x": 0, "y": 0, "month": month, "order": n_arc_points + 1})
 
 df = pd.DataFrame(wedge_rows)
-
-# Preserve month order
 df["month"] = pd.Categorical(df["month"], categories=months, ordered=True)
 
-# Colors - gradient based on rainfall values
-# Using Python Blue (#306998) as base with varying intensity
-base_blue = np.array([48, 105, 152])  # RGB for #306998
-python_yellow = np.array([255, 212, 59])  # RGB for #FFD43B
-
-# Normalize rainfall for color mapping
-min_val, max_val = min(rainfall), max(rainfall)
-colors = []
-for value in rainfall:
-    t = (value - min_val) / (max_val - min_val)  # 0 to 1
-    # Interpolate from blue to yellow
-    rgb = (1 - t) * base_blue + t * python_yellow
-    colors.append(f"#{int(rgb[0]):02x}{int(rgb[1]):02x}{int(rgb[2]):02x}")
-
-color_dict = dict(zip(months, colors, strict=True))
-
-# Create radial gridlines (circles at 20, 40, 60, 80, 100)
+# Radial gridlines (circles)
 grid_rows = []
 grid_angles = np.linspace(0, 2 * math.pi, 101)
 for radius in [20, 40, 60, 80, 100]:
     for angle in grid_angles:
         grid_rows.append({"x": radius * math.cos(angle), "y": radius * math.sin(angle), "radius": radius})
-
 grid_df = pd.DataFrame(grid_rows)
 
-# Create spoke lines (one for each month boundary)
+# Spoke lines from center to edge
 spoke_rows = []
 for i in range(n):
     angle = math.pi / 2 - (i * 2 * math.pi / n)
     spoke_rows.append({"x": 0, "y": 0, "spoke_id": i})
     spoke_rows.append({"x": 105 * math.cos(angle), "y": 105 * math.sin(angle), "spoke_id": i})
-
 spoke_df = pd.DataFrame(spoke_rows)
 
-# Create month labels positioned outside the chart
+# Month labels positioned outside the chart
 label_rows = []
 for i, month in enumerate(months):
-    # Center angle of each month's wedge
     center_angle = math.pi / 2 - ((i + 0.5) * 2 * math.pi / n)
-    label_rows.append({"label": month, "x": 115 * math.cos(center_angle), "y": 115 * math.sin(center_angle)})
-
+    label_rows.append({"label": month, "x": 120 * math.cos(center_angle), "y": 120 * math.sin(center_angle)})
 label_df = pd.DataFrame(label_rows)
 
-# Create value labels on gridlines
-value_label_rows = []
-for radius in [20, 40, 60, 80, 100]:
-    value_label_rows.append({"label": str(radius), "x": 5, "y": radius + 3})
-
+# Value labels positioned along the top-right spoke
+value_label_rows = [{"label": str(r), "x": 6, "y": r + 4} for r in [20, 40, 60, 80, 100]]
 value_label_df = pd.DataFrame(value_label_rows)
 
 # Plot
 plot = (
     ggplot()
-    # Gridlines (circles)
     + geom_line(
-        aes(x="x", y="y", group="radius"), data=grid_df, color="#CCCCCC", size=0.5, alpha=0.6, linetype="dashed"
+        aes(x="x", y="y", group="radius"), data=grid_df, color=INK_SOFT, size=0.4, alpha=0.15, linetype="dashed"
     )
-    # Spoke lines
-    + geom_line(aes(x="x", y="y", group="spoke_id"), data=spoke_df, color="#DDDDDD", size=0.3, alpha=0.5)
-    # Rose wedges
-    + geom_polygon(aes(x="x", y="y", fill="month", group="month"), data=df, color="#2C3E50", size=0.3, alpha=0.85)
-    # Month labels
-    + geom_text(aes(x="x", y="y", label="label"), data=label_df, size=14, fontweight="bold", color="#333333")
-    # Value labels
-    + geom_text(aes(x="x", y="y", label="label"), data=value_label_df, size=10, color="#666666")
-    # Colors
-    + scale_fill_manual(values=color_dict)
-    # Axis scaling
-    + scale_x_continuous(limits=(-135, 135))
-    + scale_y_continuous(limits=(-135, 135))
-    # Labels and title
-    + labs(title="Monthly Rainfall (mm) · rose-basic · plotnine · pyplots.ai")
-    # Theme for clean rose chart appearance
+    + geom_line(aes(x="x", y="y", group="spoke_id"), data=spoke_df, color=INK_SOFT, size=0.3, alpha=0.12)
+    + geom_polygon(aes(x="x", y="y", fill="month", group="month"), data=df, color=PAGE_BG, size=0.3, alpha=0.88)
+    + geom_text(aes(x="x", y="y", label="label"), data=label_df, size=14, fontweight="bold", color=INK)
+    + geom_text(aes(x="x", y="y", label="label"), data=value_label_df, size=10, color=INK_MUTED)
+    + scale_fill_manual(values=month_colors)
+    + scale_x_continuous(limits=(-142, 142))
+    + scale_y_continuous(limits=(-142, 142))
+    + labs(title="Monthly Rainfall (mm) · rose-basic · plotnine · anyplot.ai")
     + theme(
         figure_size=(12, 12),
-        plot_title=element_text(size=22, ha="center"),
+        plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
+        panel_background=element_rect(fill=PAGE_BG),
+        plot_title=element_text(size=22, ha="center", color=INK),
         axis_title=element_blank(),
         axis_text=element_blank(),
         axis_ticks=element_blank(),
         axis_line=element_blank(),
         panel_grid_major=element_blank(),
         panel_grid_minor=element_blank(),
-        panel_background=element_blank(),
+        panel_border=element_blank(),
         legend_position="none",
     )
 )
 
 # Save
-plot.save("plot.png", dpi=300)
+plot.save(f"plot-{THEME}.png", dpi=300)