Add borderRadius support to PieChartPainter

[YawarOsman]

What’s New?

• Added borderRadius capability to the PieChartPainter for enhanced customization.
• Ensured existing styles and functionality remain intact.

Why?

To provide developers with more flexibility in customizing the appearance of pie chart segments.

Testing

• Verified various borderRadius values.
• Checked for visual regressions and ensured backward compatibility.

[imaNNeo]

We don't need to have borderRadius property here in our base chart data. (So we don't need to have it for all the charts. And if we do, we should have it around the chart. Not something that only applies for the pie section paths)
So please remove it from here and just add it inside the PieChartSectionData

[imaNNeo]

This logic doesn't seem right to me.
And when I applied borderRadius: const BorderRadius.all(Radius.circular(200)), to our PieChartSample1, I saw this:

It only works with small values like 8, 16, ...
So it is not stable I would say

[imaNNeo]

I think the better idea is just to edit the shape path generation logic here:

fl_chart/lib/src/chart/pie_chart/pie_chart_painter.dart

Lines 220 to 227 in 01689ee

	var sectionPath = Path()
	..moveTo(startLine.from.dx, startLine.from.dy)
	..lineTo(startLine.to.dx, startLine.to.dy)
	..arcTo(sectionRadiusRect, startRadians, sweepRadians, false)
	..lineTo(endLine.from.dx, endLine.from.dy)
	..arcTo(centerRadiusRect, endRadians, -sweepRadians, false)
	..moveTo(startLine.from.dx, startLine.from.dy)
	..close();

We might be able to use arcTo, conicTo or cubicTo in Path

[YawarOsman]

You're right, sorry for that inconsistency

[imaNNeo]

No worries!
There's a new PR for this topic with a new implementation.
So I'll close this one for now.
Thanks a lot for your contribution and idea!

Please follow it here: #2024