Added option to added Rounded Capped PieChart

[Begarudev]

enhacement asked in this issue #1700

[imaNNeo]

Isn't it better to use the Shadow object?

Something like what we have in the LineChart:

fl_chart/lib/src/chart/line_chart/line_chart_data.dart

Lines 360 to 361 in 11d13a7

	/// Drops a shadow behind the bar line.
	final Shadow shadow;

And this is how we paint it in the drawBarShadow() function:

fl_chart/lib/src/chart/line_chart/line_chart_painter.dart

Lines 906 to 939 in 11d13a7

	void drawBarShadow(
	CanvasWrapper canvasWrapper,
	Path barPath,
	LineChartBarData barData,
	) {
	if (!barData.show || barData.shadow.color.opacity == 0.0) {
	return;
	}
	if (barPath.computeMetrics().isEmpty) {
	return;
	}
	_barPaint
	..strokeCap = barData.isStrokeCapRound ? StrokeCap.round : StrokeCap.butt
	..strokeJoin =
	barData.isStrokeJoinRound ? StrokeJoin.round : StrokeJoin.miter
	..color = barData.shadow.color
	..shader = null
	..strokeWidth = barData.barWidth
	..color = barData.shadow.color
	..maskFilter = MaskFilter.blur(
	BlurStyle.normal,
	Utils().convertRadiusToSigma(barData.shadow.blurRadius),
	);
	barPath = barPath.toDashedPath(barData.dashArray);
	barPath = barPath.shift(barData.shadow.offset);
	canvasWrapper.drawPath(
	barPath,
	_barPaint,
	);
	}

[imaNNeo]

And if it is transparent (default value), we will not draw it.

[imaNNeo]

As I see, it also tries to fix #1699.
But I think it would be better if you create separate PRs for this specific case to follow it up.