# this graph rocks: SVG charts via API

Generate beautiful SVG charts via simple URL parameters. Perfect for documentation, dashboards, and status pages.

## Chart Types
- Line charts: /line/{title}?values1=1,2,3&color=blue
- Bar charts: /bar/{title}?values=10,20,30&labels=A,B,C
- Pie charts: /pie/{title}?values=30,20,50&labels=Red,Green,Blue
- Scatter plots: /scatter/{title}?x=1,2,3&y=4,5,6
- Heatmaps: /heatmap/{title}?data=1,2,3,4&rows=2&cols=2
- Circular progress: /circular/{title}?value=73&max=100&thickness=20
- Gauge charts: /gauge/{title}?value=2.8&min=0&max=5&segments=5

## Common Parameters
- color: Comma-delimited list of colors (hex or names)
- width/height: Chart dimensions (max 1200x800)
- transparent: "dark", "light", or "no" for background
- prefix/suffix: Add $ or % to numbers
- title: Chart title
- source: Source attribution

## Examples

### Simple line chart
```
GET /line/Sales?values1=100,120,150,180&color=2563eb&prefix=$
```

### Multi-series line chart with labels
```
GET /line/Revenue%20vs%20Profit?values1=100,120,150&values2=20,25,35&labels=Q1,Q2,Q3&color=2563eb,dc2626
```

### Bar chart with custom styling
```
GET /bar/Monthly%20Stats?values=45,67,23,89&labels=Jan,Feb,Mar,Apr&color=059669&transparent=dark
```

### Pie chart
```
GET /pie/Market%20Share?values=45,30,25&labels=Product%20A,Product%20B,Product%20C&color=8b5cf6,06b6d4,f59e0b
```

### Scatter plot
```
GET /scatter/Price%20Analysis?x=10,15,20,25&y=100,150,200,250&color=dc2626&prefix=$
```

### Heatmap
```
GET /heatmap/Server%20Load?data=10,20,30,40,15,25,35,45&rows=2&cols=4&xlabels=Mon,Tue,Wed,Thu&ylabels=Server1,Server2
```

### Circular Progress
```
GET /circular/CPU%20Usage?value=73&max=100&color=dc2626&thickness=15&suffix=%
```

### Gauge Chart
```
GET /gauge/Server%20Load?value=2.8&min=0&max=5&color=059669,f59e0b,dc2626&segments=5
```

## Features
- Color-blind friendly default themes  
- Responsive SVG output
- Caching headers for CDN optimization
- Accessible markup with descriptions
- Error handling with helpful messages
- Tolerant parameter parsing

## Response Format
- Content-Type: image/svg+xml
- Cache-Control: public, max-age=3600
- Optimized SVG for fast loading
- Screen reader compatible