feat(highcharts): implement ohlc-bar (#3335)

## Implementation: `ohlc-bar` - highcharts

Implements the **highcharts** version of `ohlc-bar`.

**File:** `plots/ohlc-bar/implementations/highcharts.py`

**Parent Issue:** #3293

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20823200816)*

---------

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

Author: github-actions[bot]

plots/ohlc-bar/implementations/highcharts.py

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+"""pyplots.ai
+ohlc-bar: OHLC Bar Chart
+Library: highcharts | Python 3.13
+Quality: pending | Created: 2026-01-08
+"""
+
+import json
+import tempfile
+import time
+import urllib.request
+from datetime import datetime, timedelta
+from pathlib import Path
+
+import numpy as np
+from selenium import webdriver
+from selenium.webdriver.chrome.options import Options
+
+
+# Data - 45 trading days of simulated stock prices
+np.random.seed(42)
+
+# Start price and generate OHLC data
+start_price = 125.0
+n_days = 45
+
+# Generate realistic stock movements
+opens = [start_price]
+highs = []
+lows = []
+closes = []
+
+for i in range(n_days):
+    open_price = opens[i] if i == 0 else closes[i - 1] + np.random.randn() * 0.3
+    if i > 0:
+        opens.append(open_price)
+
+    # Daily volatility
+    daily_range = abs(np.random.randn() * 1.5) + 0.5
+    direction = np.random.choice([-1, 1], p=[0.48, 0.52])  # Slight bullish bias
+
+    close_price = open_price + direction * np.random.rand() * daily_range
+    high_price = max(open_price, close_price) + abs(np.random.randn() * 0.4)
+    low_price = min(open_price, close_price) - abs(np.random.randn() * 0.4)
+
+    highs.append(round(high_price, 2))
+    lows.append(round(low_price, 2))
+    closes.append(round(close_price, 2))
+
+opens = [round(o, 2) for o in opens]
+
+# Generate dates (trading days, skip weekends)
+start_date = datetime(2024, 9, 1)
+dates = []
+current_date = start_date
+while len(dates) < n_days:
+    if current_date.weekday() < 5:  # Monday to Friday
+        dates.append(current_date)
+    current_date += timedelta(days=1)
+
+# Format data for Highcharts: [timestamp, open, high, low, close]
+ohlc_data = []
+for i in range(n_days):
+    timestamp = int(dates[i].timestamp() * 1000)  # JavaScript timestamp in ms
+    ohlc_data.append([timestamp, opens[i], highs[i], lows[i], closes[i]])
+
+# Chart options for Highcharts Stock OHLC chart
+# Using colorblind-safe palette: Python Blue for bullish, warm amber for bearish
+chart_options = {
+    "chart": {
+        "type": "ohlc",
+        "width": 4800,
+        "height": 2700,
+        "backgroundColor": "#ffffff",
+        "marginBottom": 220,
+        "marginLeft": 250,
+        "marginRight": 80,
+        "marginTop": 150,
+        "style": {"fontFamily": "Arial, sans-serif"},
+    },
+    "title": {
+        "text": "Stock Price Analysis · ohlc-bar · highcharts · pyplots.ai",
+        "style": {"fontSize": "72px", "fontWeight": "bold", "color": "#333333"},
+        "y": 60,
+    },
+    "xAxis": {
+        "type": "datetime",
+        "title": {"text": "Date", "style": {"fontSize": "52px", "color": "#333333"}, "margin": 30},
+        "labels": {
+            "style": {"fontSize": "36px", "color": "#333333"},
+            "format": "{value:%b %d}",
+            "y": 45,
+            "step": 3,  # Show every 3rd label to prevent overlap with more data points
+        },
+        "gridLineWidth": 1,
+        "gridLineColor": "rgba(0, 0, 0, 0.15)",
+        "gridLineDashStyle": "Dash",
+        "lineWidth": 3,
+        "lineColor": "#333333",
+        "tickWidth": 3,
+        "tickColor": "#333333",
+        "tickLength": 15,
+    },
+    "yAxis": {
+        "title": {"text": "Price (USD)", "style": {"fontSize": "52px", "color": "#333333"}, "margin": 30},
+        "labels": {"style": {"fontSize": "36px", "color": "#333333"}, "format": "${value:.0f}", "x": -15},
+        "gridLineWidth": 1,
+        "gridLineColor": "rgba(0, 0, 0, 0.15)",
+        "gridLineDashStyle": "Dash",
+        "lineWidth": 3,
+        "lineColor": "#333333",
+        "opposite": False,  # Keep Y-axis on left side only
+        "tickInterval": 2,  # Show labels at $2 intervals to avoid duplicates
+    },
+    "legend": {"enabled": False},
+    "tooltip": {
+        "split": False,
+        "style": {"fontSize": "28px"},
+        "headerFormat": "<b>{point.x:%b %d, %Y}</b><br/>",
+        "pointFormat": "Open: ${point.open:.2f}<br/>"
+        + "High: ${point.high:.2f}<br/>"
+        + "Low: ${point.low:.2f}<br/>"
+        + "Close: ${point.close:.2f}",
+    },
+    "plotOptions": {
+        "ohlc": {
+            # Colorblind-safe: Python Blue for bullish, warm amber for bearish
+            "color": "#E67E22",  # Warm amber for bearish (close < open)
+            "upColor": "#306998",  # Python Blue for bullish (close > open)
+            "lineWidth": 5,  # Bar line width - visible at large size
+        }
+    },
+    "rangeSelector": {"enabled": False},
+    "navigator": {"enabled": False},
+    "scrollbar": {"enabled": False},
+    "credits": {"enabled": False},
+    "series": [{"type": "ohlc", "name": "Stock Price", "data": ohlc_data}],
+}
+
+# Download Highstock JS (includes OHLC support)
+highstock_url = "https://code.highcharts.com/stock/highstock.js"
+with urllib.request.urlopen(highstock_url, timeout=30) as response:
+    highstock_js = response.read().decode("utf-8")
+
+# Generate chart options JSON
+chart_options_json = json.dumps(chart_options)
+
+# Generate HTML with inline scripts
+html_content = f"""<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <script>{highstock_js}</script>
+</head>
+<body style="margin:0; background-color: #ffffff;">
+    <div id="container" style="width: 4800px; height: 2700px;"></div>
+    <script>
+        document.addEventListener('DOMContentLoaded', function() {{
+            Highcharts.stockChart('container', {chart_options_json});
+        }});
+    </script>
+</body>
+</html>"""
+
+# Write temp HTML file
+with tempfile.NamedTemporaryFile(mode="w", suffix=".html", delete=False, encoding="utf-8") as f:
+    f.write(html_content)
+    temp_path = f.name
+
+# Also save the HTML for interactive viewing
+with open("plot.html", "w", encoding="utf-8") as f:
+    f.write(html_content)
+
+# Take screenshot with headless Chrome
+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()
+
+# Clean up temp file
+Path(temp_path).unlink()

plots/ohlc-bar/metadata/highcharts.yaml

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+# Per-library metadata for highcharts implementation of ohlc-bar
+# Auto-generated by impl-generate.yml
+
+library: highcharts
+specification_id: ohlc-bar
+created: '2026-01-08T16:13:44Z'
+updated: '2026-01-08T16:13:44Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20823200816
+issue: 3293
+python_version: 3.13.11
+library_version: unknown
+preview_url: https://storage.googleapis.com/pyplots-images/plots/ohlc-bar/highcharts/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/ohlc-bar/highcharts/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/ohlc-bar/highcharts/plot.html
+quality_score: null
+review:
+  strengths: []
+  weaknesses: []