paint method

Implementation

void paint({
  required HMOrientation orientation,
  required RenderBox parentBox,
  required Canvas canvas,
  required Offset center,
  required double scale,
  required TextPainter labelPainter,
  required double textScaleFactor,
  required Size sizeWithOverflow,
  required Color backgroundPaintColor,
  Color? strokePaintColor,
}) {
  if (scale == 0.0) {
    // Zero scale essentially means "do not draw anything", so it's safe to just return.
    return;
  }

  final double rectangleWidth =
      _upperRectangleWidth(labelPainter, scale, textScaleFactor);
  final double horizontalShift = getHorizontalShift(
    parentBox: parentBox,
    center: center,
    labelPainter: labelPainter,
    textScaleFactor: textScaleFactor,
    sizeWithOverflow: sizeWithOverflow,
    scale: scale,
  );

  final double rectHeight = labelPainter.height + _labelPadding;
  final Rect upperRect = Rect.fromLTWH(
    -rectangleWidth / 2 + horizontalShift,
    -_triangleHeight - rectHeight,
    rectangleWidth,
    rectHeight,
  );

  final Paint fillPaint = Paint()..color = backgroundPaintColor;
  final RRect upperRRect = RRect.fromRectAndRadius(
      upperRect, const Radius.circular(_upperRectRadius));
  canvas.save();
  // Prepare the canvas for the base of the tooltip, which is relative to the
  // center of the thumb.
  if (orientation == HMOrientation.vertical) {
    canvas
      ..rotate(math.pi / 2)
      ..translate(-center.dy - labelPainter.height,
          -center.dx + (_labelPadding * 1.5));
  } else {
    canvas.translate(center.dx, center.dy - _bottomTipYOffset);
  }

  canvas.scale(scale, scale);
  canvas.drawRRect(upperRRect, fillPaint);

  // The label text is centered within the value indicator.
  final double bottomTipToUpperRectTranslateY =
      -_preferredHalfHeight / 2 - upperRect.height;
  canvas.translate(0, bottomTipToUpperRectTranslateY);
  final Offset boxCenter = Offset(horizontalShift, upperRect.height / 2);
  final Offset halfLabelPainterOffset =
      Offset(labelPainter.width / 2, labelPainter.height / 2);
  final Offset labelOffset = boxCenter - halfLabelPainterOffset;
  labelPainter.paint(canvas, labelOffset);
  canvas.restore();
}