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chart-image

Generate publication-quality chart images from data. Supports line, bar, area, point, candlestick, pie/donut, heatmap, multi-series, and stacked charts. Use when visualizing data, creating graphs, plotting time series, or generating chart images for reports/alerts. Designed for Fly.io/VPS deployments - no native compilation, no Puppeteer, no browser required. Pure Node.js with prebuilt binaries.

Why use this skill?

Generate high-quality charts for your reports and apps without the bloat. Fast, headless, and optimized for Fly.io and VPS deployments.

skill-install — Terminal

Install via CLI (Recommended)

clawhub install openclaw/skills/skills/dannyshmueli/chart-image
Or

What This Skill Does

The chart-image skill provides a robust, lightweight solution for generating professional-grade PNG visualizations directly from your data without the heavy overhead associated with traditional rendering tools. Unlike common visualization libraries that rely on browser engines like Puppeteer or Chromium, chart-image leverages Vega-Lite combined with Sharp to render charts locally. This architecture makes it exceptionally performant and perfect for resource-constrained environments such as Fly.io, small VPS instances, or Docker containers. By eliminating native compilation requirements and avoiding external rendering APIs like QuickChart.io, this tool ensures your data processing remains private, fast, and offline-capable.

Installation

To integrate this skill into your environment, use the OpenClaw hub command: clawhub install openclaw/skills/skills/dannyshmueli/chart-image

After installation, perform the one-time dependency setup by navigating to the skill directory and running: cd /data/clawd/skills/chart-image/scripts && npm install

Use Cases

This skill is designed for scenarios where automated reporting and data insight are prioritized. Common use cases include:

  • Automated Performance Reports: Generate daily server metrics, traffic spikes, or memory usage charts.
  • Financial Dashboards: Create real-time price trend visualizations, candle-stick market analysis, or multi-series portfolio comparisons.
  • Activity Monitoring: Build heatmaps to visualize patterns over time, such as system event frequency or user engagement peaks.
  • Application Alerts: Attach visual charts to notifications in Slack, Discord, or email to provide context-rich alerts rather than just raw numeric data.

Example Prompts

  1. "Generate a line chart showing the CPU usage from this JSON data: [{"x": "12:00", "y": 45}, {"x": "12:05", "y": 52}] and save it as cpu_usage.png."
  2. "Create a stacked bar chart of my weekly hours categorized by project using the following data... and title it 'Development Breakdown'."
  3. "Visualize this market data as a candlestick chart with volume bars at the bottom, comparing open, high, low, and close values."

Tips & Limitations

  • Performance: Because it bypasses browsers, charts render in under 500ms, making it ideal for high-frequency report generation.
  • Flexibility: It supports complex layouts including dual Y-axis volume overlays and multi-series comparisons. Always ensure your JSON input is correctly formatted for the specific chart type requested.
  • Constraint: This skill is strictly for headless generation. If your use case requires highly interactive, client-side zooming or complex web-based animations, consider alternative frontend-heavy libraries, as this is optimized for static file generation.

Metadata

Stars3376
Views1
Updated2026-03-24
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Add to Configuration

Paste this into your clawhub.json to enable this plugin.

{
  "plugins": {
    "official-dannyshmueli-chart-image": {
      "enabled": true,
      "auto_update": true
    }
  }
}

Tags(AI)

#visualization#charts#reporting#data-viz#performance
Safety Score: 5/5

Flags: file-write, file-read, code-execution

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