feat(pygal): implement point-basic (#6387)

## Implementation: `point-basic` - python/pygal

Implements the **python/pygal** version of `point-basic`.

**File:** `plots/point-basic/implementations/python/pygal.py`

**Parent Issue:** #2551

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/25685760658)*

---------

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/point-basic/implementations/python/pygal.py

@@ -1,92 +1,106 @@
-""" pyplots.ai
+""" anyplot.ai
 point-basic: Point Estimate Plot
-Library: pygal 3.1.0 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-30
+Library: pygal 3.1.0 | Python 3.13.13
+Quality: 87/100 | Updated: 2026-05-11
 """
 
+import os
+
 import pygal
 from pygal.style import Style
 
 
-# Data: Treatment effects with 95% confidence intervals
-categories = ["Treatment A", "Treatment B", "Treatment C", "Treatment D", "Control"]
-estimates = [2.4, 1.8, 3.2, 0.9, 0.0]
-lower_bounds = [1.6, 0.9, 2.5, -0.2, -0.5]
-upper_bounds = [3.2, 2.7, 3.9, 2.0, 0.5]
+# 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"
+BRAND = "#009E73"  # Okabe-Ito position 1
 
-# Custom style for 4800x2700 canvas
-ci_color = "#306998"
-point_color = "#FFD43B"
-ref_color = "#888888"
+# Data: Sensor calibration accuracy with 95% confidence intervals
+categories = ["Sensor A", "Sensor B", "Sensor C", "Sensor D", "Sensor E"]
+estimates = [0.3, 0.8, -0.2, 1.1, 0.5]
+lower_bounds = [-0.4, 0.1, -0.9, 0.3, -0.1]
+upper_bounds = [1.0, 1.5, 0.5, 1.9, 1.1]
 
+# Custom style for 4800x2700 canvas with theme support
 custom_style = Style(
-    background="white",
-    plot_background="white",
-    foreground="#333333",
-    foreground_strong="#333333",
-    foreground_subtle="#999999",
-    colors=(ref_color, ci_color, ci_color, ci_color, ci_color, ci_color, point_color),
-    title_font_size=72,
-    label_font_size=48,
-    major_label_font_size=42,
-    legend_font_size=42,
-    value_font_size=36,
-    stroke_width=6,
-    guide_stroke_color="#e0e0e0",
+    background=PAGE_BG,
+    plot_background=PAGE_BG,
+    foreground=INK,
+    foreground_strong=INK,
+    foreground_subtle=INK_SOFT,
+    colors=(BRAND, "#D55E00", "#0072B2", "#CC79A7", "#E69F00", "#56B4E9", "#F0E442"),
+    title_font_size=28,
+    label_font_size=22,
+    major_label_font_size=18,
+    legend_font_size=16,
+    value_font_size=14,
+    stroke_width=3,
+    guide_stroke_color="rgba(26,26,23,0.10)" if THEME == "light" else "rgba(240,239,232,0.10)",
 )
 
 # Create XY chart for point estimates with confidence intervals
 chart = pygal.XY(
     width=4800,
     height=2700,
     style=custom_style,
-    title="point-basic · pygal · pyplots.ai",
-    x_title="Effect Size",
+    title="point-basic · pygal · anyplot.ai",
+    x_title="Calibration Error (μV)",
     show_legend=True,
     legend_at_bottom=True,
     legend_at_bottom_columns=3,
-    show_y_guides=True,
+    show_y_guides=False,
     show_x_guides=True,
-    dots_size=30,
+    dots_size=24,
     stroke=False,
     margin_left=120,
     margin_right=120,
     margin_top=150,
     margin_bottom=180,
-    xrange=(-1.5, 4.5),
+    xrange=(-1.5, 2.5),
     range=(0, 6),
 )
 
 # Map categories to y-values (numeric) - reversed for top-to-bottom display
 y_positions = list(range(len(categories), 0, -1))
 
-# Add reference line at zero first (so it appears behind other elements)
+# Add reference line at zero (null hypothesis)
 ref_line = [(0, 0.3), (0, 5.7)]
-chart.add("Reference (x=0)", ref_line, stroke=True, show_dots=False, stroke_width=3)
+chart.add("Reference (zero error)", ref_line, stroke=True, show_dots=False, stroke_width=4)
 
-# Add each CI as a separate series (to avoid connecting lines)
+# Add each CI as a separate series with caps
 for i, (low, high, y) in enumerate(zip(lower_bounds, upper_bounds, y_positions, strict=True)):
-    ci_data = [(low, y), (high, y)]
-    # First CI gets label, others are hidden from legend using None
+    # CI line with caps (drawn as separate segments)
+    cap_height = 0.15
+    ci_data = [
+        (low, y - cap_height),  # left cap bottom
+        (low, y + cap_height),  # left cap top
+        (low, y),  # start of CI line
+        (high, y),  # end of CI line
+        (high, y - cap_height),  # right cap bottom
+        (high, y + cap_height),  # right cap top
+    ]
     if i == 0:
-        chart.add("95% CI", ci_data, stroke=True, show_dots=False, stroke_width=8)
+        chart.add("95% CI", ci_data, stroke=True, show_dots=False, stroke_width=5)
     else:
-        chart.add(None, ci_data, stroke=True, show_dots=False, stroke_width=8)
+        chart.add(None, ci_data, stroke=True, show_dots=False, stroke_width=5)
 
 # Add point estimates (on top of CI lines)
 point_data = [(est, y) for est, y in zip(estimates, y_positions, strict=True)]
-chart.add("Point Estimate", point_data, dots_size=32, stroke=False)
+chart.add("Point Estimate", point_data, dots_size=28, stroke=False)
 
-# Custom y-axis labels with category names - use major labels
+# Custom y-axis labels with category names
 chart.y_labels_major = [5, 4, 3, 2, 1]
 chart.y_labels = [
-    {"value": 5, "label": "Treatment A"},
-    {"value": 4, "label": "Treatment B"},
-    {"value": 3, "label": "Treatment C"},
-    {"value": 2, "label": "Treatment D"},
-    {"value": 1, "label": "Control"},
+    {"value": 5, "label": "Sensor A"},
+    {"value": 4, "label": "Sensor B"},
+    {"value": 3, "label": "Sensor C"},
+    {"value": 2, "label": "Sensor D"},
+    {"value": 1, "label": "Sensor E"},
 ]
 
-# Save as PNG and HTML
-chart.render_to_png("plot.png")
-chart.render_to_file("plot.html")
+# Save as PNG and HTML with theme suffix
+chart.render_to_png(f"plot-{THEME}.png")
+with open(f"plot-{THEME}.html", "wb") as f:
+    f.write(chart.render())