Improve PieChart default colors

@@ -83,11 +83,9 @@ class Invoice {
   static const _darkColor = PdfColors.blueGrey800;
   static const _darkColor = PdfColors.blueGrey800;
   static const _lightColor = PdfColors.white;
   static const _lightColor = PdfColors.white;
 
 
-  PdfColor get _baseTextColor =>
-      baseColor.luminance < 0.5 ? _lightColor : _darkColor;
+  PdfColor get _baseTextColor => baseColor.isLight ? _lightColor : _darkColor;
 
 
-  PdfColor get _accentTextColor =>
-      baseColor.luminance < 0.5 ? _lightColor : _darkColor;
+  PdfColor get _accentTextColor => baseColor.isLight ? _lightColor : _darkColor;
 
 
   double get _total =>
   double get _total =>
       products.map<double>((p) => p.total).reduce((a, b) => a + b);
       products.map<double>((p) => p.total).reduce((a, b) => a + b);

@@ -282,17 +282,13 @@ Future<Uint8List> generateReport(
                 datasets: List<pw.Dataset>.generate(dataTable.length, (index) {
                 datasets: List<pw.Dataset>.generate(dataTable.length, (index) {
                   final data = dataTable[index];
                   final data = dataTable[index];
                   final color = chartColors[index % chartColors.length];
                   final color = chartColors[index % chartColors.length];
-                  final textColor =
-                      color.luminance < 0.2 ? PdfColors.white : PdfColors.black;
-
                   final value = (data[2] as num).toDouble();
                   final value = (data[2] as num).toDouble();
                   final pct = (value / expense * 100).round();
                   final pct = (value / expense * 100).round();
-
                   return pw.PieDataSet(
                   return pw.PieDataSet(
                     legend: '${data[0]}\n$pct%',
                     legend: '${data[0]}\n$pct%',
                     value: value,
                     value: value,
                     color: color,
                     color: color,
-                    legendStyle: pw.TextStyle(fontSize: 10, color: textColor),
+                    legendStyle: pw.TextStyle(fontSize: 10),
                   );
                   );
                 }),
                 }),
               ),
               ),

@@ -13,6 +13,7 @@
 - Passthrough SpanningWidget on SingleChildWidget and StatelessWidget
 - Passthrough SpanningWidget on SingleChildWidget and StatelessWidget
 - Improve TextOverflow support
 - Improve TextOverflow support
 - Fix Table horizontalInside borders
 - Fix Table horizontalInside borders
+- Improve PieChart default colors
 
 
 ## 3.2.0
 ## 3.2.0
 
 

@@ -180,6 +180,16 @@ class PdfColor {
     return math.pow((component + 0.055) / 1.055, 2.4).toDouble();
     return math.pow((component + 0.055) / 1.055, 2.4).toDouble();
   }
   }
 
 
+  /// Determines whether the given [PdfColor] is light.
+  bool get isLight => !isDark;
+
+  /// Determines whether the given [PdfColor] is dark.
+  bool get isDark {
+    final relativeLuminance = luminance;
+    const kThreshold = 0.15;
+    return (relativeLuminance + 0.05) * (relativeLuminance + 0.05) > kThreshold;
+  }
+
   /// Get the luminance
   /// Get the luminance
   double get luminance {
   double get luminance {
     final R = _linearizeColorComponent(red);
     final R = _linearizeColorComponent(red);
@@ -240,6 +250,12 @@ class PdfColor {
   int get hashCode => toInt();
   int get hashCode => toInt();
 }
 }
 
 
+class PdfColorGrey extends PdfColor {
+  /// Create a grey color
+  const PdfColorGrey(double color, [double alpha = 1.0])
+      : super(color, color, color, alpha);
+}
+
 /// Represents an CMYK color
 /// Represents an CMYK color
 class PdfColorCmyk extends PdfColor {
 class PdfColorCmyk extends PdfColor {
   /// Creates a CMYK color
   /// Creates a CMYK color

@@ -126,13 +126,14 @@ class PieDataSet extends Dataset {
     this.legendAlign,
     this.legendAlign,
     this.legendPosition = PieLegendPosition.auto,
     this.legendPosition = PieLegendPosition.auto,
     this.legendLineWidth = 1.0,
     this.legendLineWidth = 1.0,
-    this.legendLineColor = PdfColors.black,
+    PdfColor? legendLineColor,
     Widget? legendWidget,
     Widget? legendWidget,
     this.legendOffset = 20,
     this.legendOffset = 20,
   })  : drawBorder = drawBorder ?? borderColor != null && color != borderColor,
   })  : drawBorder = drawBorder ?? borderColor != null && color != borderColor,
         assert((drawBorder ?? borderColor != null && color != borderColor) ||
         assert((drawBorder ?? borderColor != null && color != borderColor) ||
             drawSurface),
             drawSurface),
         _legendWidget = legendWidget,
         _legendWidget = legendWidget,
+        legendLineColor = legendLineColor ?? color,
         super(
         super(
           legend: legend,
           legend: legend,
           color: color,
           color: color,
@@ -201,7 +202,18 @@ class PieDataSet extends Dataset {
 
 
     _legendWidget ??= legend == null
     _legendWidget ??= legend == null
         ? null
         ? null
-        : Text(legend!, style: legendStyle, textAlign: _legendAlign);
+        : RichText(
+            text: TextSpan(
+              children: [TextSpan(text: legend!, style: legendStyle)],
+              style: TextStyle(
+                  color: lp == PieLegendPosition.inside
+                      ? color!.isLight
+                          ? PdfColors.white
+                          : PdfColors.black
+                      : null),
+            ),
+            textAlign: _legendAlign,
+          );
 
 
     if (_legendWidget != null) {
     if (_legendWidget != null) {
       _legendWidget!.layout(context,
       _legendWidget!.layout(context,