feat(highcharts): implement histogram-stacked (#2639)

## Implementation: `histogram-stacked` - highcharts

Implements the **highcharts** version of `histogram-stacked`.

**File:** `plots/histogram-stacked/implementations/highcharts.py`

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20594562099)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/histogram-stacked/implementations/highcharts.py

@@ -0,0 +1,155 @@
+""" pyplots.ai
+histogram-stacked: Stacked Histogram
+Library: highcharts unknown | Python 3.13.11
+Quality: 92/100 | Created: 2025-12-30
+"""
+
+import tempfile
+import time
+import urllib.request
+from pathlib import Path
+
+import numpy as np
+from highcharts_core.chart import Chart
+from highcharts_core.options import HighchartsOptions
+from highcharts_core.options.series.bar import ColumnSeries
+from selenium import webdriver
+from selenium.webdriver.chrome.options import Options
+
+
+# Data: Generate three groups with different distributions
+np.random.seed(42)
+group_a = np.random.normal(loc=45, scale=12, size=150)  # Centered around 45
+group_b = np.random.normal(loc=55, scale=10, size=120)  # Centered around 55
+group_c = np.random.normal(loc=65, scale=15, size=100)  # Centered around 65
+
+# Combine all data to determine common bin edges
+all_data = np.concatenate([group_a, group_b, group_c])
+bin_edges = np.histogram_bin_edges(all_data, bins=15)
+bin_centers = [(bin_edges[i] + bin_edges[i + 1]) / 2 for i in range(len(bin_edges) - 1)]
+bin_labels = [f"{bin_edges[i]:.0f}-{bin_edges[i + 1]:.0f}" for i in range(len(bin_edges) - 1)]
+
+# Calculate histogram counts for each group
+counts_a, _ = np.histogram(group_a, bins=bin_edges)
+counts_b, _ = np.histogram(group_b, bins=bin_edges)
+counts_c, _ = np.histogram(group_c, bins=bin_edges)
+
+# Create chart
+chart = Chart(container="container")
+chart.options = HighchartsOptions()
+
+# Chart options
+chart.options.chart = {
+    "type": "column",
+    "width": 4800,
+    "height": 2700,
+    "backgroundColor": "#ffffff",
+    "marginBottom": 300,
+}
+
+# Title
+chart.options.title = {
+    "text": "histogram-stacked · highcharts · pyplots.ai",
+    "style": {"fontSize": "72px", "fontWeight": "bold"},
+}
+
+# Subtitle
+chart.options.subtitle = {"text": "Measurement Distribution by Sensor Type", "style": {"fontSize": "42px"}}
+
+# X-axis (categories for bins)
+chart.options.x_axis = {
+    "categories": bin_labels,
+    "title": {"text": "Measurement Range", "style": {"fontSize": "48px"}, "margin": 40},
+    "labels": {"style": {"fontSize": "28px"}},
+}
+
+# Y-axis
+chart.options.y_axis = {
+    "title": {"text": "Frequency", "style": {"fontSize": "48px"}},
+    "labels": {"style": {"fontSize": "36px"}},
+    "gridLineWidth": 1,
+    "gridLineColor": "rgba(0,0,0,0.1)",
+    "stackLabels": {"enabled": False},
+}
+
+# Plot options for stacking
+chart.options.plot_options = {
+    "column": {"stacking": "normal", "borderWidth": 1, "borderColor": "#ffffff", "dataLabels": {"enabled": False}}
+}
+
+# Legend
+chart.options.legend = {
+    "enabled": True,
+    "itemStyle": {"fontSize": "36px"},
+    "align": "right",
+    "verticalAlign": "top",
+    "layout": "vertical",
+    "x": -50,
+    "y": 100,
+}
+
+# Colors - colorblind-safe palette
+colors = ["#306998", "#FFD43B", "#9467BD"]
+
+# Add series for each group
+series_a = ColumnSeries()
+series_a.data = [int(c) for c in counts_a]
+series_a.name = "Sensor A"
+series_a.color = colors[0]
+
+series_b = ColumnSeries()
+series_b.data = [int(c) for c in counts_b]
+series_b.name = "Sensor B"
+series_b.color = colors[1]
+
+series_c = ColumnSeries()
+series_c.data = [int(c) for c in counts_c]
+series_c.name = "Sensor C"
+series_c.color = colors[2]
+
+chart.add_series(series_a)
+chart.add_series(series_b)
+chart.add_series(series_c)
+
+# Export to PNG via Selenium
+highcharts_url = "https://code.highcharts.com/highcharts.js"
+with urllib.request.urlopen(highcharts_url, timeout=30) as response:
+    highcharts_js = response.read().decode("utf-8")
+
+# Generate HTML with inline scripts
+html_str = chart.to_js_literal()
+html_content = f"""<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <script>{highcharts_js}</script>
+</head>
+<body style="margin:0;">
+    <div id="container" style="width: 4800px; height: 2700px;"></div>
+    <script>{html_str}</script>
+</body>
+</html>"""
+
+# Write temp HTML and take screenshot
+with tempfile.NamedTemporaryFile(mode="w", suffix=".html", delete=False, encoding="utf-8") as f:
+    f.write(html_content)
+    temp_path = f.name
+
+chrome_options = Options()
+chrome_options.add_argument("--headless")
+chrome_options.add_argument("--no-sandbox")
+chrome_options.add_argument("--disable-dev-shm-usage")
+chrome_options.add_argument("--disable-gpu")
+chrome_options.add_argument("--window-size=4800,2700")
+
+driver = webdriver.Chrome(options=chrome_options)
+driver.get(f"file://{temp_path}")
+time.sleep(5)
+driver.save_screenshot("plot.png")
+driver.quit()
+
+Path(temp_path).unlink()
+
+# Also save HTML for interactive version
+with open("plot.html", "w", encoding="utf-8") as f:
+    f.write(html_content)

plots/histogram-stacked/metadata/highcharts.yaml

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+library: highcharts
+specification_id: histogram-stacked
+created: '2025-12-30T10:42:46Z'
+updated: '2025-12-30T10:50:48Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20594562099
+issue: 0
+python_version: 3.13.11
+library_version: unknown
+preview_url: https://storage.googleapis.com/pyplots-images/plots/histogram-stacked/highcharts/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/histogram-stacked/highcharts/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/histogram-stacked/highcharts/plot.html
+quality_score: 92
+review:
+  strengths:
+  - Excellent colorblind-safe palette with clear visual distinction between all three
+    groups
+  - Proper implementation of stacked histogram using common bin edges calculated from
+    combined data
+  - Clean, professional appearance with well-sized text elements for high-resolution
+    output
+  - Correct title format and meaningful subtitle adding context
+  - Good use of Highcharts-specific features like plot_options stacking configuration
+  weaknesses:
+  - Output image height is 2561px instead of the expected 2700px (minor dimension
+    mismatch)
+  - Axis labels lack units (e.g., could be "Measurement Range (units)" and "Frequency
+    (count)")