comparison.md

Symbol comparison

comparisons overlays other instruments on the main chart as lines. Each ComparisonSeries is rebased by default: aligned to the main series at the left edge of the visible window, so both lines start together and their divergence shows relative performance. The anchor moves as you pan, so the comparison always reflects the visible period.

KChartWidget(
  btcCandles,
  ChartColors(),
  comparisons: [
    ComparisonSeries.ofCandles(label: 'ETH', candles: ethCandles),
    ComparisonSeries(
      label: 'DXY',
      points: [for (final p in dollarIndex) (time: p.time, value: p.close)],
      color: Colors.tealAccent,
      style: LineStyle.dashed,
    ),
  ],
);

Scale

ComparisonScale.price plots the series at its actual prices on the same axis. Use it only when both instruments share units — for example, a future and its spot price, or two tenors of the same curve.

Alignment

• Points are matched to candles by timestamp, not position, so instruments with different bar schedules align correctly. Each candle uses the last point at or before its time.
• Gaps in the data break the line.
• Candles before the comparison's first point show no value.

Display

• The price range expands to include all comparisons.
• Each comparison has its own legend row showing its percentage change.
• Colours are assigned from ChartColors.comparisonColors unless the series specifies one.

Helpers

For custom rendering, the following functions are exported:

Function	Purpose
alignComparison	Aligns a series to a list of candles
comparisonAnchor	Computes the rebasing anchor for a window
comparisonPriceAt	Maps a value to its plotted price

---

← All docs · Package README