​
Overview

Line charts are essential for displaying trends and patterns in data over a period. Cristalyse provides an elegant API for crafting intuitive line charts.


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Basic Line Chart

Display a simple line chart to show trends:

data = [
  {'month': 'Jan', 'value': 30},
  {'month': 'Feb', 'value': 45},
  {'month': 'Mar', 'value': 60},
];

CristalyseChart()
  .data(data)
  .mapping(x: 'month', y: 'value')
  .geomLine(strokeWidth: 2.0, color: Colors.blue)
  .scaleXOrdinal()
  .scaleYContinuous()
  .build();

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Multi-Series Line Chart

Compare series by plotting multiple lines:

data = [
  {'month': 'Jan', 'platform': 'iOS', 'users': 1200},
  {'month': 'Jan', 'platform': 'Android', 'users': 800},
  {'month': 'Feb', 'platform': 'iOS', 'users': 1350},
  {'month': 'Feb', 'platform': 'Android', 'users': 950},
];

CristalyseChart()
  .data(data)
  .mapping(x: 'month', y: 'users', color: 'platform')
  .geomLine(strokeWidth: 3.0)
  .geomPoint(size: 4.0)
  .scaleXOrdinal()
  .scaleYContinuous(min: 0)
  .theme(ChartTheme.defaultTheme())
  .build();

​
Progressive Drawing

Animate lines progressively from start to end:

CristalyseChart()
  .data(data)
  .mapping(x: 'month', y: 'value')
  .geomLine(strokeWidth: 2.0)
  .animate(duration: Duration(milliseconds: 1500))
  .build();

​
Styling Lines

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Dashed and Dotted Lines

Change line styles for variety and emphasis:

CristalyseChart()
  .data(data)
  .mapping(x: 'month', y: 'value')
  .geomLine(
    strokeWidth: 3.0,
    style: LineStyle.dashed,
  )
  .build();

​
Highlighting Points

Enhance visual storytelling by emphasizing points:

CristalyseChart()
  .data(data)
  .mapping(x: 'month', y: 'value')
  .geomLine(strokeWidth: 2.0)
  .geomPoint(size: 6.0, color: Colors.red)
  .build();

​
Interactive Features

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Tooltips

Provide context with informative tooltips:

CristalyseChart()
  .data(data)
  .mapping(x: 'month', y: 'value')
  .geomLine()
  .interaction(
    tooltip: TooltipConfig(
      builder: (point) {
        return Text(
          'Value: ${point.getDisplayValue('value')}',
          style: TextStyle(color: Colors.white),
        );
      },
    ),
  )
  .build();

​
Performance Optimizations

Cristalyse is designed to handle large datasets efficiently. For optimal performance:

  • Keep stroke width moderate
  • Use lightweight themes
  • Optimize data points and mapping categories

Ready to explore more chart types? Back to Chart Gallery