drawPolyline method

dynamic drawPolyline(
  1. double lastPrice,
  2. double curPrice,
  3. Canvas canvas,
  4. double lastX,
  5. double curX,
)

Implementation

drawPolyline(double lastPrice, double curPrice, Canvas canvas, double lastX,
    double curX) {
  mLinePath ??= Path();
  if (lastX == curX) lastX = 0; //起点位置填充
  mLinePath!.moveTo(lastX, getY(lastPrice));
  mLinePath!.cubicTo((lastX + curX) / 2, getY(lastPrice), (lastX + curX) / 2,
      getY(curPrice), curX, getY(curPrice));

  mLineFillShader ??= LinearGradient(
    begin: Alignment.topCenter,
    end: Alignment.bottomCenter,
    tileMode: TileMode.clamp,
    colors: [this.chartColors.lineFillColor, Colors.transparent],
  ).createShader(Rect.fromLTRB(
      chartRect.left, chartRect.top, chartRect.right, chartRect.bottom));
  mLineFillPaint..shader = mLineFillShader;

  mLineFillPath ??= Path();

  mLineFillPath!.moveTo(lastX, chartRect.height + chartRect.top);
  mLineFillPath!.lineTo(lastX, getY(lastPrice));
  mLineFillPath!.cubicTo((lastX + curX) / 2, getY(lastPrice),
      (lastX + curX) / 2, getY(curPrice), curX, getY(curPrice));
  mLineFillPath!.lineTo(curX, chartRect.height + chartRect.top);
  mLineFillPath!.close();

  canvas.drawPath(mLineFillPath!, mLineFillPaint);
  mLineFillPath!.reset();

  canvas.drawPath(mLinePath!,
      mLinePaint..strokeWidth = (mLineStrokeWidth / scaleX).clamp(0.1, 1.0));
  mLinePath!.reset();
}