Custom curve

[Afroz-Shaikh]

Feature 🚀

This pull request adds a new feature called CustomCurve to the LinearGauge. With this feature, users can now add Bezier curves to their gauges, as well as modify various parameters to customize the look and feel of the curves.,
This feature includes the following options:

• Bezier or straight paths: Users can choose whether to use a Bezier curve or a straight line to connect the start and end values of the gauge.
• Painting style: Users can select from several different painting styles, including gradient fills and textured patterns.
• Start and end values: Users can customize the start and end values of the gauge, which will affect the shape of the curve.

Usage

LinearGauge(
            curves: [
              CustomCurve(
                  midPoint: 50,
                  startHeight: 0,
                  endHeight: 0,
                  midHeight: 100,
                  paintStyle: PaintStyle.fill,
                  curvePosition: CurvePosition.top)
            ],
            rulers: const RulerStyle(
              rulerPosition: RulerPosition.bottom,
            ),
          ),

Changes

• ✅ New Feature added
• ✅ Adjusted ViewBox Accordingly
• ✅ Golden Tests for CustomCurve Added
• ✅ Documented Feature