chart-splat

通过 Chart Splat API 生成漂亮的图表。当用户要求以图表、图形或绘图的形式创建、生成或可视化数据时使用。支持折线图、条形图、饼图、圆环图、雷达图、极区图和烛台/OHLC 图表。返回 PNG 图像。

## 概述（中文）

通过 Chart Splat API 生成漂亮的图表。当用户要求以图表、图形或绘图的形式创建、生成或可视化数据时使用。支持折线图、条形图、饼图、圆环图、雷达图、极区图和烛台/OHLC 图表。返回 PNG 图像。

## 原文

# Chart Splat

Generate beautiful charts from data using the Chart Splat API. Charts are rendered server-side with Chart.js and returned as PNG images.

## Supported Chart Types

| Type | Best For |
|------|----------|
| `line` | Trends over time |
| `bar` | Comparing categories |
| `pie` | Parts of a whole |
| `doughnut` | Parts of a whole (with center space) |
| `radar` | Multivariate comparison |
| `polarArea` | Comparing categories with radial layout |
| `candlestick` | Financial/crypto OHLC price data |
| `ohlc` | Financial/crypto OHLC price data (bar variant) |

## Method 1: CLI (Preferred)

Use the `chartsplat` CLI via npx. No install required.

```bash
npx -y chartsplat-cli bar \
  --labels "Q1,Q2,Q3,Q4" \
  --data "50,75,60,90" \
  --title "Quarterly Revenue" \
  --color "#8b5cf6" \
  -o chart.png
```

### CLI Options

| Flag | Description |
|------|-------------|
| `-l, --labels <csv>` | Comma-separated labels |
| `-d, --data <csv>` | Comma-separated numeric values |
| `-t, --title <text>` | Chart title |
| `--label <text>` | Dataset label for legend |
| `-c, --color <hex>` | Background color |
| `-w, --width <px>` | Image width (default: 800) |
| `--height <px>` | Image height (default: 600) |
| `-o, --output <file>` | Output file path (default: chart.png) |
| `--config <file>` | JSON config file for complex charts |

### CLI Chart Commands

```bash
npx -y chartsplat-cli line -l "Mon,Tue,Wed,Thu,Fri" -d "100,200,150,300,250" -o line.png
npx -y chartsplat-cli bar -l "A,B,C" -d "10,20,30" -o bar.png
npx -y chartsplat-cli pie -l "Red,Blue,Green" -d "30,50,20" -o pie.png
npx -y chartsplat-cli doughnut -l "Yes,No,Maybe" -d "60,25,15" -o doughnut.png
npx -y chartsplat-cli radar -l "Speed,Power,Range,Durability,Precision" -d "80,90,70,85,95" -o radar.png
npx -y chartsplat-cli polararea -l "N,E,S,W" -d "40,30,50,20" -o polar.png
npx -y chartsplat-cli candlestick --config ohlc.json -o chart.png
```

### Candlestick Charts

Candlestick and OHLC charts require a JSON config file since the data format is more complex than a simple CSV list. Use `--config` to provide a file with OHLC data points.

```bash
npx -y chartsplat-cli candlestick --config ohlc.json -o candlestick.png
```

Config format (`ohlc.json`):

```json
{
  "type": "candlestick",
  "data": {
    "datasets": [{
      "label": "VVV Price",
      "data": [
        { "x": 1740441600000, "o": 4.23, "h": 4.80, "l": 4.10, "c": 4.45 },
        { "x": 1740528000000, "o": 4.45, "h": 5.50, "l": 4.30, "c": 5.34 },
        { "x": 1740614400000, "o": 5.34, "h": 6.20, "l": 5.10, "c": 5.97 }
      ]
    }]
  }
}
```

Each OHLC data point requires: `x` (numeric timestamp in ms, or a date string like `"2025-02-25"`), `o` (open), `h` (high), `l` (low), `c` (close).

### Complex Charts via Config File

For multi-dataset or customized charts, write a JSON config file then pass it to the CLI:

```bash
npx -y chartsplat-cli bar --config chart-config.json -o chart.png
```

See [examples/sample-charts.json](examples/sample-charts.json) for config file examples and [references/api-reference.md](references/api-reference.md) for the full config schema.

## Method 2: Helper Script

Use the bundled script for quick generation without installing the CLI:

```bash
node scripts/generate-chart.js bar "Q1,Q2,Q3,Q4" "50,75,60,90" "Revenue" chart.png
```

Or with a config file:

```bash
node scripts/generate-chart.js --config chart-config.json -o chart.png
```

## Output Handling

- Charts are saved as PNG files to the specified output path
- Default output is `chart.png` in the current directory
- For messaging platforms (Discord, Slack), return the file path: `MEDIA: /path/to/chart.png`
- The CLI and helper script handle base64 decoding automatically

## Error Handling

| Error | Cause | Fix |
|-------|-------|-----|
| `API key required` | Missing `CHARTSPLAT_API_KEY` | Set the env var in agent config |
| `Invalid API key` | Wrong or revoked key | Generate a new key at chartsplat.com/dashboard |
| `Rate limit exceeded` | Monthly quota reached | Upgrade plan or wait for reset |
| `Invalid chart configuration` | Bad request payload | Check that `data.labels` and `data.datasets` are present (candlestick/ohlc only require `data.datasets`) |

## Tips

- Always provide both `labels` and `data` arrays of the same length
- Use hex colors (e.g., `#8b5cf6`) for consistent styling
- For pie/doughnut charts, use an array of colors for `backgroundColor` to color each segment
- Default dimensions (800x600) work well for most uses; increase for presentations
- The `--config` flag accepts any valid Chart.js configuration for full customization