refactor: move normalizeBorder to the utils class for reusability

Author: haashem

lib/src/chart/bar_chart/bar_chart_data.dart

@@ -299,20 +299,6 @@ class BarChartGroupData with EquatableMixin {
       ];
 }
 
-Border? _normalizeBorder(Border? border, double width) {
-  if (border == null) {
-    return null;
-  }
-
-  final utils = Utils();
-  return Border(
-    top: utils.normalizeBorderSide(border.top, width),
-    right: utils.normalizeBorderSide(border.right, width),
-    bottom: utils.normalizeBorderSide(border.bottom, width),
-    left: utils.normalizeBorderSide(border.left, width),
-  );
-}
-
 /// Holds data about rendering each rod (or bar) in the [BarChart].
 class BarChartRodData with EquatableMixin {
   /// [BarChart] renders rods vertically from zero to [toY],
@@ -364,7 +350,7 @@ class BarChartRodData with EquatableMixin {
         width = width ?? 8,
         borderRadius = Utils().normalizeBorderRadius(borderRadius, width ?? 8),
         borderSide = Utils().normalizeBorderSide(borderSide, width ?? 8),
-        border = _normalizeBorder(border, width ?? 8),
+        border = Utils().normalizeBorder(border, width ?? 8),
         backDrawRodData = backDrawRodData ?? BackgroundBarChartRodData(),
         rodStackItems = rodStackItems ?? const [];
 

lib/src/utils/utils.dart

@@ -107,6 +107,20 @@ class Utils {
     return borderSide.copyWith(width: borderWidth);
   }
 
+  /// Decreases each side of [border] to <= width / 2.
+  Border? normalizeBorder(Border? border, double width) {
+    if (border == null) {
+      return null;
+    }
+
+    return Border(
+      top: normalizeBorderSide(border.top, width),
+      right: normalizeBorderSide(border.right, width),
+      bottom: normalizeBorderSide(border.bottom, width),
+      left: normalizeBorderSide(border.left, width),
+    );
+  }
+
   /// Returns an efficient interval for showing axis titles, or grid lines or ...
   ///
   /// If there isn't any provided interval, we use this function to calculate an interval to apply,

test/utils/utils_test.dart

@@ -115,6 +115,32 @@ void main() {
     expect(Utils().normalizeBorderSide(input2, 40), output2);
   });
 
+  test('normalizeBorder()', () {
+    const input1 = Border(
+      top: BorderSide(width: 4),
+      right: BorderSide(width: 8),
+      bottom: BorderSide(width: 10),
+      left: BorderSide(width: 2),
+    );
+    const output1 = input1;
+    expect(Utils().normalizeBorder(input1, 40), output1);
+
+    const input2 = Border(
+      top: BorderSide(width: 24),
+      right: BorderSide(width: 30),
+      bottom: BorderSide(width: 21),
+      left: BorderSide(),
+    );
+    const output2 = Border(
+      top: BorderSide(width: 20),
+      right: BorderSide(width: 20),
+      bottom: BorderSide(width: 20),
+      left: BorderSide(),
+    );
+    expect(Utils().normalizeBorder(input2, 40), output2);
+    expect(Utils().normalizeBorder(null, 40), isNull);
+  });
+
   test('lerp gradient', () {
     expect(
       lerpGradient(