[Feature Request]: StackedPieChart (or radial stacked bar chart)

[jay-k98]

Description

It would be very useful to extend the current PieChart with support for stacked slices. Instead of each slice containing a single value, a slice could contain a list of values (segments). These segments would be rendered as concentric radial bands inside the slice, similar to a stacked bar chart but in polar coordinates.

Example

Proposed Solution

class StackedPieChartData extends BaseChartData {
  final List<StackedPieSectionData> sections;
  // ... other than that just the same props like in [PieChartData]
}

class StackedPieSectionData {
  final double weight;
  final double radius;
  final List<StackedPieSegmentData> segments;
  // ... other than that just the same props like in [PieChartSectionData]
}

class StackedPieSegmentData {
  final double value;
  final Color color;
  final Gradient? gradient;
}

Alternatives

I have considered Alternatives within and outside of fl_chart:

• fl_chart: Put two or more [PieChart] inside a [Stack] -> Problem: Need to sync touch interactions and animations, which is tedious
• Other packages: I tried using graphic, but the API is not convenient and features such as animations when selecting a slice was not possible

[jay-k98]

Hi @imaNNeo :) I hope you like this feature. I already created a PR: https://github.com/imaNNeo/fl_chart/pull/2004 looking forward to your feedback!