feat(plotnine): implement ecdf-basic (#9489)

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

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

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

**Parent Issue:** #976

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/28160686084)*

---------

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/ecdf-basic/implementations/python/plotnine.py

@@ -1,78 +1,101 @@
 """ anyplot.ai
 ecdf-basic: Basic ECDF Plot
-Library: plotnine 0.15.3 | Python 3.14.4
-Quality: 91/100 | Updated: 2026-04-24
+Library: plotnine 0.15.7 | Python 3.13.14
+Quality: 89/100 | Updated: 2026-06-25
 """
 
 import os
+import sys
 
 import numpy as np
 import pandas as pd
-from plotnine import (
+
+
+# Avoid shadowing the plotnine library when this file is run directly
+_cwd = os.getcwd()
+sys.path = [p for p in sys.path if os.path.abspath(p) != _cwd]
+
+from plotnine import (  # noqa: E402
     aes,
+    annotate,
     element_blank,
     element_line,
     element_rect,
     element_text,
     geom_hline,
-    geom_step,
     geom_vline,
     ggplot,
     ggsave,
     labs,
     scale_x_continuous,
     scale_y_continuous,
+    stat_ecdf,
     theme,
     theme_minimal,
 )
 
 
-# Theme
+# Theme tokens (Imprint palette)
 THEME = os.getenv("ANYPLOT_THEME", "light")
 PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
 ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
 INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
 INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
-BRAND = "#009E73"
+INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
+BRAND = "#009E73"  # Imprint palette position 1
 
-# Data: test scores — normal distribution centered at 50
+# Data: test scores — normal distribution
 np.random.seed(42)
 scores = np.random.randn(200) * 15 + 50
+q1 = float(np.percentile(scores, 25))
+median_score = float(np.median(scores))
+q3 = float(np.percentile(scores, 75))
 
-# Compute ECDF
-sorted_scores = np.sort(scores)
-ecdf_y = np.arange(1, len(sorted_scores) + 1) / len(sorted_scores)
-median_score = np.median(sorted_scores)
+df = pd.DataFrame({"score": scores})
 
-df = pd.DataFrame({"score": sorted_scores, "ecdf": ecdf_y})
+title = "ecdf-basic · python · plotnine · anyplot.ai"
 
-# Plot
+# Plot — stat_ecdf computes ECDF internally via plotnine's stat layer
 plot = (
-    ggplot(df, aes(x="score", y="ecdf"))
-    + geom_hline(yintercept=0.5, color=INK_SOFT, size=0.6, linetype="dotted", alpha=0.7)
-    + geom_vline(xintercept=median_score, color=INK_SOFT, size=0.6, linetype="dotted", alpha=0.7)
-    + geom_step(color=BRAND, size=2)
-    + labs(x="Test Score (points)", y="Cumulative Proportion", title="ecdf-basic · plotnine · anyplot.ai")
+    ggplot(df, aes(x="score"))
+    # IQR shaded band — highlights the interquartile range (middle 50%)
+    + annotate("rect", xmin=q1, xmax=q3, ymin=0.0, ymax=1.0, fill=BRAND, alpha=0.06)
+    # Quartile reference crosshairs (Q1, median, Q3)
+    + geom_hline(yintercept=0.25, color=INK_SOFT, size=0.5, linetype="dotted", alpha=0.55)
+    + geom_hline(yintercept=0.50, color=INK_SOFT, size=0.6, linetype="dotted", alpha=0.70)
+    + geom_hline(yintercept=0.75, color=INK_SOFT, size=0.5, linetype="dotted", alpha=0.55)
+    + geom_vline(xintercept=q1, color=INK_SOFT, size=0.5, linetype="dotted", alpha=0.55)
+    + geom_vline(xintercept=median_score, color=INK_SOFT, size=0.6, linetype="dotted", alpha=0.70)
+    + geom_vline(xintercept=q3, color=INK_SOFT, size=0.5, linetype="dotted", alpha=0.55)
+    # ECDF step line — rendered on top of reference elements
+    + stat_ecdf(geom="step", color=BRAND, size=1.1)
+    # Quartile annotations — teach readers how to extract percentile information
+    + annotate("text", x=q1 + 1.5, y=0.16, label=f"Q1: {q1:.1f}", color=INK_SOFT, size=3.5, ha="left")
+    + annotate(
+        "text", x=median_score + 1.5, y=0.08, label=f"Median: {median_score:.1f}", color=INK_SOFT, size=4.0, ha="left"
+    )
+    + annotate("text", x=q3 + 1.5, y=0.80, label=f"Q3: {q3:.1f}", color=INK_SOFT, size=3.5, ha="left")
+    + labs(x="Test Score (points)", y="Cumulative Proportion", title=title)
     + scale_x_continuous(expand=(0.01, 0))
     + scale_y_continuous(limits=(0, 1), breaks=np.arange(0, 1.1, 0.1), expand=(0.01, 0))
     + theme_minimal()
     + theme(
-        figure_size=(16, 9),
+        figure_size=(8, 4.5),
         plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
         panel_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
         panel_border=element_blank(),
-        panel_grid_major=element_line(color=INK, size=0.3, alpha=0.10),
+        panel_grid_major=element_line(color=INK, size=0.3, alpha=0.15),
         panel_grid_minor=element_blank(),
         axis_line=element_line(color=INK_SOFT, size=0.6),
         axis_ticks=element_line(color=INK_SOFT, size=0.5),
-        text=element_text(color=INK, size=14),
-        plot_title=element_text(color=INK, size=24, weight="medium", ha="left"),
-        axis_title=element_text(color=INK, size=20),
-        axis_text=element_text(color=INK_SOFT, size=16),
+        text=element_text(color=INK, size=7),
+        plot_title=element_text(color=INK, size=12, weight="medium", ha="left"),
+        axis_title=element_text(color=INK, size=10),
+        axis_text=element_text(color=INK_SOFT, size=8),
         legend_background=element_rect(fill=ELEVATED_BG, color=INK_SOFT),
-        legend_text=element_text(color=INK_SOFT, size=16),
-        legend_title=element_text(color=INK, size=16),
+        legend_text=element_text(color=INK_SOFT, size=8),
+        legend_title=element_text(color=INK, size=8),
     )
 )
 
-ggsave(plot, filename=f"plot-{THEME}.png", dpi=300, width=16, height=9)
+ggsave(plot, filename=f"plot-{THEME}.png", dpi=400, width=8, height=4.5)