feat(pygal): implement venn-labeled-items (#5381)

## Implementation: `venn-labeled-items` - python/pygal

Implements the **python/pygal** version of `venn-labeled-items`.

**File:** `plots/venn-labeled-items/implementations/python/pygal.py`

**Parent Issue:** #5364

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/24923831951)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/venn-labeled-items/implementations/python/pygal.py

@@ -0,0 +1,233 @@
+""" anyplot.ai
+venn-labeled-items: Chartgeist-Style Venn Diagram with Labeled Items
+Library: pygal 3.1.0 | Python 3.14.4
+Quality: 86/100 | Created: 2026-04-25
+"""
+
+import importlib
+import math
+import os
+import re
+import sys
+from collections import defaultdict
+
+
+# Drop the script directory from sys.path so the `pygal` package resolves, not this file
+sys.path[:] = [p for p in sys.path if os.path.abspath(p or ".") != os.path.dirname(os.path.abspath(__file__))]
+pygal = importlib.import_module("pygal")
+Style = importlib.import_module("pygal.style").Style
+cairosvg = importlib.import_module("cairosvg")
+
+
+# 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"
+
+# Okabe-Ito categorical palette: brand green, vermillion, blue
+COLOR_A = "#009E73"
+COLOR_B = "#D55E00"
+COLOR_C = "#0072B2"
+
+# Symmetric three-circle Venn: equilateral triangle of centers (apex up)
+RADIUS = 1.0
+OFFSET = RADIUS / math.sqrt(3)
+ax, ay = -OFFSET * math.sin(math.radians(60)), -OFFSET * math.cos(math.radians(60))
+bx, by = OFFSET * math.sin(math.radians(60)), -OFFSET * math.cos(math.radians(60))
+cx, cy = 0.0, OFFSET
+
+circles = [
+    {"name": "OVERHYPED", "color": COLOR_A, "center": (ax, ay), "label_xy": (ax - 0.95, ay - 1.10), "anchor": "start"},
+    {
+        "name": "ACTUALLY USEFUL",
+        "color": COLOR_B,
+        "center": (bx, by),
+        "label_xy": (bx + 0.95, by - 1.10),
+        "anchor": "end",
+    },
+    {"name": "SECRETLY LOVED", "color": COLOR_C, "center": (cx, cy), "label_xy": (cx, cy + 1.18), "anchor": "middle"},
+]
+
+# Items distributed across the seven interior zones
+items_raw = [
+    ("NFTs", "A"),
+    ("Metaverse", "A"),
+    ("Web3", "A"),
+    ("Google Maps", "B"),
+    ("Sticky Notes", "B"),
+    ("USB Hubs", "B"),
+    ("Karaoke", "C"),
+    ("Postcards", "C"),
+    ("Smartphones", "AB"),
+    ("Email", "AB"),
+    ("Crocs", "AC"),
+    ("Pumpkin Spice", "AC"),
+    ("Spotify", "BC"),
+    ("Dolly Parton", "BC"),
+    ("Sourdough", "ABC"),
+    ("TikTok", "ABC"),
+]
+
+# Centroids of each Venn region in chart-data units
+zone_centers = {
+    "A": (ax - 0.55, ay + 0.05),
+    "B": (bx + 0.55, by + 0.05),
+    "C": (cx, cy + 0.50),
+    "AB": (0.0, by - 0.32),
+    "AC": (-0.45, 0.20),
+    "BC": (0.45, 0.20),
+    "ABC": (0.0, -0.05),
+}
+
+LINE_HEIGHT = 0.13
+zone_to_items = defaultdict(list)
+for label, zone in items_raw:
+    zone_to_items[zone].append(label)
+
+item_points = []
+for zone, labels in zone_to_items.items():
+    zx, zy = zone_centers[zone]
+    n = len(labels)
+    start_y = zy + (n - 1) * LINE_HEIGHT / 2
+    for i, label in enumerate(labels):
+        item_points.append({"value": (zx, start_y - i * LINE_HEIGHT), "label": label})
+
+
+# Parametric points for a circle outline (closed polyline)
+def circle_outline(center, r, n=120):
+    cx0, cy0 = center
+    return [(cx0 + r * math.cos(2 * math.pi * i / n), cy0 + r * math.sin(2 * math.pi * i / n)) for i in range(n + 1)]
+
+
+# Style — derived from theme tokens
+custom_style = Style(
+    background=PAGE_BG,
+    plot_background=PAGE_BG,
+    foreground=INK,
+    foreground_strong=INK,
+    foreground_subtle=INK_MUTED,
+    colors=(COLOR_A, COLOR_B, COLOR_C, INK, INK, INK, INK),
+    opacity="1",
+    opacity_hover="1",
+    stroke_width=6,
+    stroke_opacity=".90",
+    stroke_opacity_hover=".90",
+    title_font_size=72,
+    label_font_size=22,
+    major_label_font_size=22,
+    legend_font_size=22,
+    value_font_size=42,
+    value_label_font_size=42,
+    title_font_family="serif",
+    label_font_family="serif",
+    major_label_font_family="serif",
+    legend_font_family="serif",
+    value_font_family="serif",
+    value_label_font_family="serif",
+    transition="0",
+)
+
+# Plot — square 3600×3600 canvas suits the radial Venn layout
+chart = pygal.XY(
+    width=3600,
+    height=3600,
+    style=custom_style,
+    title="Pop Culture Vibes 2026 · venn-labeled-items · pygal · anyplot.ai",
+    show_legend=False,
+    show_x_labels=False,
+    show_y_labels=False,
+    show_x_guides=False,
+    show_y_guides=False,
+    show_minor_x_labels=False,
+    show_minor_y_labels=False,
+    xrange=(-2.30, 2.30),
+    range=(-2.30, 2.30),
+    margin=20,
+    spacing=0,
+    show_dots=True,
+    dots_size=0,
+    print_labels=True,
+    print_values=False,
+    pretty_print=True,
+)
+
+# Three circle outlines (one series per circle) — fills are added via post-processing
+for c in circles:
+    chart.add("", circle_outline(c["center"], RADIUS), stroke=True, fill=False, show_dots=False)
+
+# Item names — text-only placement at zone centroids
+chart.add("Items", item_points, stroke=False, show_dots=True)
+
+# Category names — same labeling mechanism, restyled by post-processor below
+for c in circles:
+    chart.add("", [{"value": c["label_xy"], "label": c["name"]}], stroke=False, show_dots=True)
+
+svg = chart.render().decode("utf-8")
+
+
+# Post-process — pygal cannot natively (a) fill a closed polyline or (b) per-label
+# typography. Both are added directly to the SVG output.
+def fill_circle_path(svg_text, serie_idx, color, opacity):
+    pattern = re.compile(
+        r'(<g class="series serie-' + str(serie_idx) + r' color-\d+">\s*<path[^>]*?)class="line reactive nofill"'
+    )
+    return pattern.sub(
+        r'\1class="line reactive" style="fill:' + color + ";fill-opacity:" + str(opacity) + r';stroke-width:7"',
+        svg_text,
+        count=1,
+    )
+
+
+for idx, c in enumerate(circles):
+    svg = fill_circle_path(svg, idx, c["color"], 0.18)
+
+
+# Restyle category labels by matching their text content
+def restyle_label(svg_text, label_text, color, anchor, font_size):
+    pattern = re.compile(r'<text(\s+x="[^"]*"\s+y="[^"]*")\s+class="label">' + re.escape(label_text) + r"</text>")
+    return pattern.sub(
+        r'<text\1 class="label" style="font-size:'
+        + str(font_size)
+        + ";font-style:italic;font-weight:bold;text-anchor:"
+        + anchor
+        + ";fill:"
+        + color
+        + r'">'
+        + label_text
+        + "</text>",
+        svg_text,
+        count=1,
+    )
+
+
+for c in circles:
+    svg = restyle_label(svg, c["name"], c["color"], c["anchor"], 64)
+
+# Pygal auto-picks white text whenever a series color is dark — that turns
+# the item labels invisible on our cream/charcoal background. Rewrite those
+# rules in place so labels inherit the theme INK instead.
+svg = re.sub(r"(\.text-overlay \.color-\d+ text \{\s*fill:\s*)[^;}\s]+", r"\1" + INK, svg)
+# Bump the rendered label size to the 42px set in Style above; pygal's
+# CSS hard-codes 36px ignoring `value_label_font_size` for XY plots.
+svg = re.sub(r"(\.text-overlay text\.label \{[^}]*font-size:\s*)\d+px", r"\g<1>42px", svg)
+
+# Editorial subtitle injected at a fixed canvas position, theme-aware
+subtitle = (
+    '<g class="anyplot-subtitle"><text x="1800" y="3540" '
+    'style="font-family:serif;font-style:italic;font-size:42px;fill:' + INK_SOFT + ';text-anchor:middle">'
+    "A field guide to sixteen things, three feelings, and seven overlapping truths"
+    "</text></g>"
+)
+svg = svg.replace("</svg>", subtitle + "</svg>")
+
+
+# Save — interactive SVG embedded in HTML, plus rasterized PNG via cairosvg
+with open(f"plot-{THEME}.svg", "w") as f:
+    f.write(svg)
+
+with open(f"plot-{THEME}.html", "w") as f:
+    f.write("<!doctype html><html><body style='margin:0;background:" + PAGE_BG + "'>" + svg + "</body></html>")
+
+cairosvg.svg2png(bytestring=svg.encode("utf-8"), write_to=f"plot-{THEME}.png", output_width=3600, output_height=3600)