feat(pygal): implement acf-pacf

plots/acf-pacf/implementations/python/pygal.py

@@ -1,9 +1,18 @@
-""" pyplots.ai
+""" anyplot.ai
 acf-pacf: Autocorrelation and Partial Autocorrelation (ACF/PACF) Plot
-Library: pygal 3.1.0 | Python 3.14.3
-Quality: 85/100 | Created: 2026-03-14
+Library: pygal 3.1.0 | Python 3.13.13
+Quality: 85/100 | Updated: 2026-06-10
 """
 
+import os
+import sys
+
+
+# Remove this file's directory from sys.path so `import pygal` resolves to the
+# installed package, not this script (which shares the same name).
+_this_dir = os.path.dirname(os.path.abspath(__file__))
+sys.path = [p for p in sys.path if os.path.abspath(p or ".") != _this_dir]
+
 import io
 import xml.etree.ElementTree as ET
 
@@ -15,7 +24,29 @@
 from statsmodels.tsa.stattools import acf, pacf
 
 
-# Data - Synthetic monthly airline-style passenger data with trend and seasonality
+# Theme-adaptive tokens (Imprint palette)
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
+
+# Imprint categorical palette — canonical order, theme-independent
+IMPRINT_PALETTE = ("#009E73", "#C475FD", "#4467A3", "#BD8233", "#AE3030", "#2ABCCD", "#954477", "#99B314")
+ANYPLOT_AMBER = "#DDCC77"  # significance threshold lines (caution/warning role)
+
+# Semantic color roles for this chart
+HIGHLIGHT_COLOR = IMPRINT_PALETTE[0]  # #009E73 — significant bars (first series, always)
+MUTED_BAR_COLOR = INK_MUTED  # non-significant bars
+CONF_LINE_COLOR = ANYPLOT_AMBER  # 95% CI threshold lines
+ZERO_LINE_COLOR = INK_MUTED  # zero baseline
+
+
+def hex_to_rgb(hex_str):
+    h = hex_str.lstrip("#")
+    return tuple(int(h[i : i + 2], 16) for i in (0, 2, 4))
+
+
+# Data — synthetic monthly airline-style passenger data with trend and seasonality
 np.random.seed(42)
 n_obs = 200
 t = np.arange(n_obs)
@@ -24,164 +55,170 @@
 noise = np.random.normal(0, 2, n_obs)
 passengers = 100 + trend + seasonal + noise
 
-# Compute ACF and PACF
+# ACF/PACF computation
 n_lags = 36
 acf_values = acf(passengers, nlags=n_lags, fft=True)
 pacf_values = pacf(passengers, nlags=n_lags, method="ywm")
 conf_bound = 1.96 / np.sqrt(n_obs)
 
-# Color palette - refined for publication quality
-highlight_color = "#306998"
-muted_color = "#B8D4E8"
-conf_line_color = "#C0392B"
-bg_color = "#FAFAFA"
-text_color = "#1A1A2E"
-grid_color = "#E8ECF0"
-zero_line_color = "#95A5A6"
-
+# Style — Imprint palette, theme-adaptive chrome; canvas = 3200×1800 (two 3200×900 panels)
 custom_style = Style(
-    background="white",
-    plot_background=bg_color,
-    foreground=text_color,
-    foreground_strong=text_color,
-    foreground_subtle=grid_color,
-    colors=(highlight_color,),
-    title_font_size=48,
-    label_font_size=30,
-    major_label_font_size=30,
-    legend_font_size=24,
-    value_font_size=18,
+    background=PAGE_BG,
+    plot_background=PAGE_BG,
+    foreground=INK,
+    foreground_strong=INK,
+    foreground_subtle=INK_MUTED,
+    colors=IMPRINT_PALETTE,
+    title_font_size=66,
+    label_font_size=56,
+    major_label_font_size=44,
+    legend_font_size=44,
+    value_font_size=36,
+    stroke_width=2.5,
     font_family="'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
     title_font_family="'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
     label_font_family="'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
     value_font_family="'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
 )
 
-# Y-axis ranges tailored to actual data with slight padding
+# Y-axis ranges tailored to data
 acf_min, acf_max = -0.5, 1.1
 pacf_min, pacf_max = -0.5, 1.0
 
-# Common chart config - high spacing for narrow stem-like bars
+# Each panel: 3200×900; two panels stacked → 3200×1800 landscape
 common_config = {
-    "width": 4800,
-    "height": 1300,
+    "width": 3200,
+    "height": 900,
     "style": custom_style,
     "show_legend": False,
     "show_y_guides": True,
     "show_x_guides": False,
-    "margin": 25,
-    "margin_left": 120,
+    "margin": 20,
+    "margin_left": 130,
     "margin_right": 60,
-    "spacing": 100,
+    "spacing": 80,
     "truncate_label": -1,
     "print_values": False,
     "show_minor_x_labels": False,
     "x_labels_major_every": 4,
     "rounded_bars": 2,
-    "y_labels_major_count": 5,
 }
 
-# ACF chart
+# ACF chart (top panel)
 acf_chart = pygal.Bar(
     **common_config,
     x_title="",
     y_title="ACF",
-    title="acf-pacf · pygal · pyplots.ai",
+    title="acf-pacf · python · pygal · anyplot.ai",
     margin_bottom=10,
     margin_top=30,
     range=(acf_min, acf_max),
 )
 acf_chart.x_labels = [str(i) for i in range(n_lags + 1)]
+acf_chart.y_labels = [-0.4, -0.2, 0.0, 0.5, 1.0]
 acf_chart.add(
     "ACF",
-    [{"value": round(v, 4), "color": highlight_color if abs(v) > conf_bound else muted_color} for v in acf_values],
+    [{"value": round(v, 4), "color": HIGHLIGHT_COLOR if abs(v) > conf_bound else MUTED_BAR_COLOR} for v in acf_values],
 )
 
-# PACF chart
+# PACF chart (bottom panel)
 pacf_chart = pygal.Bar(
     **common_config, x_title="Lag", y_title="PACF", title="", margin_bottom=70, margin_top=5, range=(pacf_min, pacf_max)
 )
 pacf_chart.x_labels = [str(i) for i in range(1, n_lags + 1)]
+pacf_chart.y_labels = [-0.4, -0.2, 0.0, 0.5, 1.0]
 pacf_chart.add(
     "PACF",
-    [{"value": round(v, 4), "color": highlight_color if abs(v) > conf_bound else muted_color} for v in pacf_values[1:]],
+    [
+        {"value": round(v, 4), "color": HIGHLIGHT_COLOR if abs(v) > conf_bound else MUTED_BAR_COLOR}
+        for v in pacf_values[1:]
+    ],
 )
 
-# Render SVGs and inject confidence lines (pygal lacks native reference lines)
+# SVG namespace registration
 ns = "http://www.w3.org/2000/svg"
 ET.register_namespace("", ns)
 ET.register_namespace("xlink", "http://www.w3.org/1999/xlink")
 
-png_images = []
-for chart, y_min, y_max in [(acf_chart, acf_min, acf_max), (pacf_chart, pacf_min, pacf_max)]:
+
+def _inject_ci_lines(chart, y_min, y_max):
+    """Inject CI dashed lines and zero baseline into pygal's SVG (no native reference-line API)."""
     root = ET.fromstring(chart.render())
     plot_group = next((g for g in root.iter(f"{{{ns}}}g") if g.get("class", "") == "plot"), None)
     if plot_group is not None:
         bg_rect = next((r for r in plot_group.iter(f"{{{ns}}}rect") if r.get("class", "") == "background"), None)
         if bg_rect is not None:
             pw, ph = float(bg_rect.get("width")), float(bg_rect.get("height"))
             y_range = y_max - y_min
+            # 95% CI bounds (dashed amber lines)
             for cv in [conf_bound, -conf_bound]:
                 ly = (y_max - cv) / y_range * ph
                 line = ET.SubElement(plot_group, f"{{{ns}}}line")
                 line.set("x1", "0")
                 line.set("y1", f"{ly:.1f}")
                 line.set("x2", str(pw))
                 line.set("y2", f"{ly:.1f}")
-                line.set("stroke", conf_line_color)
+                line.set("stroke", CONF_LINE_COLOR)
                 line.set("stroke-width", "3")
                 line.set("stroke-dasharray", "18,10")
-                line.set("opacity", "0.75")
-            # Zero baseline emphasis
+                line.set("opacity", "0.9")
+            # Zero baseline (muted solid line)
             zy = (y_max - 0) / y_range * ph
             zline = ET.SubElement(plot_group, f"{{{ns}}}line")
             zline.set("x1", "0")
             zline.set("y1", f"{zy:.1f}")
             zline.set("x2", str(pw))
             zline.set("y2", f"{zy:.1f}")
-            zline.set("stroke", zero_line_color)
+            zline.set("stroke", ZERO_LINE_COLOR)
             zline.set("stroke-width", "2.5")
             zline.set("opacity", "0.6")
+    return root
 
-    png_images.append(cairosvg.svg2png(bytestring=ET.tostring(root), output_width=4800, output_height=1300))
 
-# Compose final image
-acf_img = Image.open(io.BytesIO(png_images[0]))
-pacf_img = Image.open(io.BytesIO(png_images[1]))
-combined = Image.new("RGB", (4800, 2700), "white")
-combined.paste(acf_img, (0, 50))
-combined.paste(pacf_img, (0, 1350))
-
-# Subtle divider line between charts
+# Render both panels
+panels = []
+svg_strings = []
+for chart, y_min, y_max in [(acf_chart, acf_min, acf_max), (pacf_chart, pacf_min, pacf_max)]:
+    root = _inject_ci_lines(chart, y_min, y_max)
+    svg_bytes = ET.tostring(root)
+    svg_strings.append(ET.tostring(root, encoding="unicode"))
+    png_data = cairosvg.svg2png(bytestring=svg_bytes, output_width=3200, output_height=900)
+    img = Image.open(io.BytesIO(png_data)).convert("RGB")
+    img = img.resize((3200, 900), Image.LANCZOS)
+    panels.append(img)
+
+# Compose 3200×1800 landscape canvas
+combined = Image.new("RGB", (3200, 1800), hex_to_rgb(PAGE_BG))
+combined.paste(panels[0], (0, 0))
+combined.paste(panels[1], (0, 900))
+
+# Subtle divider between panels
 draw = ImageDraw.Draw(combined)
-draw.line([(120, 1350), (4740, 1350)], fill="#DEE2E6", width=2)
+draw.line([(130, 900), (3140, 900)], fill=hex_to_rgb(INK_MUTED), width=1)
 
-# Confidence bound annotation - positioned in upper-right margin area
+# CI annotation in upper-right margin
 try:
     font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 30)
 except OSError:
     font = ImageFont.load_default()
-draw.text((4200, 68), f"95% CI: ±{conf_bound:.3f}", fill=conf_line_color, font=font)
-
-combined.save("plot.png", dpi=(300, 300))
+draw.text((2640, 24), f"95% CI: ±{conf_bound:.3f}", fill=CONF_LINE_COLOR, font=font)
 
-# HTML version with interactive SVGs
-acf_svg = acf_chart.render(is_unicode=True).replace('<?xml version="1.0" encoding="utf-8"?>', "")
-pacf_svg = pacf_chart.render(is_unicode=True).replace('<?xml version="1.0" encoding="utf-8"?>', "")
+combined.save(f"plot-{THEME}.png", dpi=(300, 300))
 
+# Interactive HTML output (pygal renders interactive SVG charts)
 html_content = (
     "<!DOCTYPE html>\n<html>\n<head>\n"
-    "    <title>acf-pacf · pygal · pyplots.ai</title>\n"
+    "    <title>acf-pacf · python · pygal · anyplot.ai</title>\n"
     "    <style>\n"
-    "        body { font-family: 'Helvetica Neue', sans-serif; background: white; margin: 0; padding: 20px; }\n"
+    f"        body {{ font-family: 'Helvetica Neue', sans-serif; background: {PAGE_BG}; color: {INK}; margin: 0; padding: 20px; }}\n"
     "        .container { max-width: 1200px; margin: 0 auto; }\n"
     "        .chart { width: 100%; margin: 10px 0; }\n"
     "    </style>\n</head>\n<body>\n"
     "    <div class='container'>\n"
-    f"        <div class='chart'>{acf_svg}</div>\n"
-    f"        <div class='chart'>{pacf_svg}</div>\n"
+    f"        <div class='chart'>{svg_strings[0]}</div>\n"
+    f"        <div class='chart'>{svg_strings[1]}</div>\n"
     "    </div>\n</body>\n</html>"
 )
 
-with open("plot.html", "w") as f:
+with open(f"plot-{THEME}.html", "w") as f:
     f.write(html_content)