sclass TradingCandlePainter extends ScaledDiagram {
  settable L<TradingCandle> candles;
  
  int spikeWidth = 1;
  Color shortColor = java.awt.Color.blue;
  Color longColor = java.awt.Color.yellow;
  
  new L<TradingPosition> positions;
  
  // how many lines are drawn to indicate percent changes
  settable double percentLineDistance = 0.05;
  
  BufferedImage render() {
    var run = new TradingRun(candles);
    verticalRange(doubleRange(run.min(), run.max()));
    horizontalRange(doubleRange(run.startTime().unixDate(), run.endTime().unixDate()));
    
    // Make black image
    var img = blackImage(w, h);
    var g = img.createGraphics();
    
    // Draw percent lines
    double percentStep = center(verticalRange)*percentLineDistance/100;
    for (double y = verticalRange.start; y <= verticalRange.end; y += percentStep) {
      var yy = iround(yToScreen(y));
      drawLine(g, 0, yy, w-1, yy, Color.gray);
    }
    
    // Draw candles
    
    var nCandles = l(candles);
    
    for i to nCandles: {
      var candle = candles.get(i);
      var x1 = xRange().start()+doubleRatio(i, nCandles)*xRange().length();
      var x2 = xRange().start()+doubleRatio(i+1, nCandles)*xRange().length();
      x2 = blend(x1, x2, 0.75);
      var xCenter = avg(x1, x2);
      var y1 = yToScreen(candle.max());
      var y2 = yToScreen(candle.min());
      var yStart = yToScreen(candle.start());
      var yEnd = yToScreen(candle.end());
      
      // draw "spikes"
      var r = doubleRectFromPoints(xCenter, y1, xCenter+spikeWidth, y2);
      fillRect(g, growRectBottom(1, toRect_round(r)), candle.color());
      
      // draw candle body
      r = doubleRectFromPoints(x1, min(yStart, yEnd), x2, max(yStart, yEnd));
      fillRect(g, growRectBottom(1, toRect_round(r)), candle.color());
    }
    
    for (position : positions) {
      var time = position.openingTime();
      var price = position.openingPrice();
      var x = xToScreen(time);
      var y = yToScreen(price);
      
      var color = colorFromHex(position.relativeValue() > 0 ? "1da2b4" : "f1493f");
      
      // Mark opening point
      fillRect(g, rectAroundPt(iround(x), iround(y), 10), color);
          
      if (not(position.isOpen())) {
        time = position.closingTime();
        price = position.closingPrice();
        var x2 = xToScreen(time);
        var y2 = yToScreen(price);
        drawArrowBetweenPoints(g, toPt_round(doublePt(x, y)), toPt_round(doublePt(x2, y2)), color);
      }
    }
    
    ret img;
  }
}