drafter_finance

Native, multiplatform trading charts for Flutter — candlestick / K-line, OHLC bars, line, area, baseline, histogram and volume — with technical indicators (SMA / EMA / RSI / MACD / Bollinger) and a magnet crosshair. No WebView.

The Flutter port of the Drafter Finance SDK. It shares its architecture — and its golden numbers — with the Compose (Kotlin) and SwiftUI ports, so all three render identically.

Architecture

A thin CustomPainter over a bundled pure-Dart engine (lib/src/engine/):

• Engine — scales, viewport, indicators, crosshair hit-testing. No Flutter import; emits a platform-agnostic display list (Scene).
• Renderer (this package) — walks the display list with native Canvas APIs (Catmull-Rom smoothing, soft gradient fills, a left-to-right reveal animation), with a per-scene draw-op cache so the reveal stays allocation-free per frame.

Usage

import 'package:drafter_finance/drafter_finance.dart';

// Candlestick with a magnet crosshair (drag to scrub):
FinanceCandlestickChart(candles: candles);

// TradingView color preset:
FinanceCandlestickChart(
  candles: candles,
  style: TradingViewTheme.instance.candle(),
);

// Value-series charts:
FinanceLineChart(values: closes);
FinanceAreaChart(values: closes);
FinanceBaselineChart(values: closes, style: DrafterTheme.instance.baseline(closes.first));
FinanceHistogramChart(values: changes);
FinanceVolumeChart(candles: candles);
FinanceBarChart(candles: candles);

Two themes ship in the box: DrafterTheme (calm premium palette, MA overlays) and TradingViewTheme (TradingView Lightweight Charts' exact default colors). Every style is a value you can copyWith(...) to customize.

See the example for a runnable demo of every chart type.

License

Apache 2.0 — see LICENSE.