paint method

@override void paint(Context context)

Draw itself and its children, according to the calculated box.offset

Implementation

@override
void paint(Context context) {
  super.paint(context);

  final adjustedValue = value.clamp(0.00001, .99999);
  final rx = box!.width / 2;
  final ry = box!.height / 2;
  const angleStart = math.pi / 2;
  final angleEnd = angleStart - math.pi * 2 * adjustedValue;
  final startTop = PdfPoint(
    box!.left + rx + math.cos(angleStart) * rx,
    box!.bottom + ry + math.sin(angleStart) * ry,
  );
  final endTop = PdfPoint(
    box!.left + rx + math.cos(angleEnd) * rx,
    box!.bottom + ry + math.sin(angleEnd) * ry,
  );
  final startBottom = PdfPoint(
    box!.left + rx + math.cos(angleStart) * (rx - strokeWidth),
    box!.bottom + ry + math.sin(angleStart) * (ry - strokeWidth),
  );
  final endBottom = PdfPoint(
    box!.left + rx + math.cos(angleEnd) * (rx - strokeWidth),
    box!.bottom + ry + math.sin(angleEnd) * (ry - strokeWidth),
  );

  if (backgroundColor != null && value < 1) {
    context.canvas
      ..moveTo(startTop.x, startTop.y)
      ..bezierArc(
        startTop.x,
        startTop.y,
        rx,
        ry,
        endTop.x,
        endTop.y,
        large: adjustedValue < .5,
        sweep: true,
      )
      ..lineTo(endBottom.x, endBottom.y)
      ..bezierArc(
        endBottom.x,
        endBottom.y,
        rx - strokeWidth,
        ry - strokeWidth,
        startBottom.x,
        startBottom.y,
        large: adjustedValue < .5,
      )
      ..lineTo(startTop.x, startTop.y)
      ..setFillColor(backgroundColor)
      ..fillPath();
  }

  if (value > 0) {
    context.canvas
      ..moveTo(startTop.x, startTop.y)
      ..bezierArc(
        startTop.x,
        startTop.y,
        rx,
        ry,
        endTop.x,
        endTop.y,
        large: adjustedValue > .5,
      )
      ..lineTo(endBottom.x, endBottom.y)
      ..bezierArc(
        endBottom.x,
        endBottom.y,
        rx - strokeWidth,
        ry - strokeWidth,
        startBottom.x,
        startBottom.y,
        large: adjustedValue > .5,
        sweep: true,
      )
      ..lineTo(startTop.x, startTop.y)
      ..setFillColor(color ?? PdfColors.indigo)
      ..fillPath();
  }
}