fix: Use num instead of int for Horizontal Decoration

example/lib/charts/showcase_chart_screen.dart

@@ -169,7 +169,7 @@ final List<ChartState<bool>> _chartStates = [
         verticalValuesPadding: const EdgeInsets.only(top: 24.0),
         horizontalAxisValueFromValue: (value) => '${value + 1}h',
         verticalAxisValueFromIndex: (value) =>
-            ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][value],
+            ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][value.toInt()],
         textStyle: TextStyle(fontSize: 14.0, color: Colors.black45),
       ),
     ],

lib/chart/render/decorations/horizontal_axis_decoration.dart

@@ -9,12 +9,12 @@ enum HorizontalLegendPosition {
   end,
 }
 
-typedef AxisValueFromValue = String Function(int value);
+typedef AxisValueFromValue = String Function(num value);
 
 /// Default axis generator, it will just take current index, convert it to string and return it.
-String defaultAxisValue(int index) => '$index';
+String defaultAxisValue(num index) => '$index';
 
-typedef ShowLineForValue = bool Function(int value);
+typedef ShowLineForValue = bool Function(num value);
 
 /// Decoration for drawing horizontal lines on the chart, decoration can add horizontal axis legend
 ///
@@ -146,7 +146,7 @@ class HorizontalAxisDecoration extends DecorationPainter {
     final _maxValue = state.data.maxValue - state.data.minValue;
 
     for (var i = 0; i * axisStep <= _maxValue; i++) {
-      final _defaultValue = (axisStep * i + state.data.minValue).toInt();
+      final _defaultValue = axisStep * i + state.data.minValue;
       final _value = axisValue.call(_defaultValue);
       if ((_longestText?.length ?? 0) < _value.length) {
         _longestText = _value;
@@ -168,7 +168,7 @@ class HorizontalAxisDecoration extends DecorationPainter {
     final gridPath = Path();
 
     for (var i = 0; i * scale * axisStep <= scale * _maxValue; i++) {
-      final _defaultValue = (axisStep * i + state.data.minValue).toInt();
+      final _defaultValue = axisStep * i + state.data.minValue;
 
       final _isPositionStart = legendPosition == HorizontalLegendPosition.start;
       final _startLine = _isPositionStart

test/golden/complex/showcase_test.dart

@@ -135,8 +135,15 @@ void main() {
                       bottom: -8.0, right: 8.0, left: 8.0),
                   verticalValuesPadding: const EdgeInsets.only(top: 24.0),
                   horizontalAxisValueFromValue: (value) => '${value + 1}h',
-                  verticalAxisValueFromIndex: (value) =>
-                      ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][value],
+                  verticalAxisValueFromIndex: (value) => [
+                    'Mon',
+                    'Tue',
+                    'Wed',
+                    'Thu',
+                    'Fri',
+                    'Sat',
+                    'Sun'
+                  ][value.toInt()],
                   textStyle: defaultTextStyle.copyWith(
                       fontSize: 12.0, color: Colors.black45),
                 ),

test/golden/decoration/horizontal_decoration_test.dart

@@ -117,6 +117,18 @@ void main() {
           ],
         ),
       ),
+      GoldenTestScenario(
+        name: 'Decimal Lines',
+        child: getDefaultChart(
+          backgroundDecorations: [
+            HorizontalAxisDecoration(
+              showLineForValue: (value) => true,
+              lineWidth: 3.0,
+              axisStep: 4.5,
+            ),
+          ],
+        ),
+      ),
     ]);
   });
 }