Add some color functions

+# 1.3.5
+* Add some color functions
+* Remove color constants from PdfColor, use PdfColors
+
 # 1.3.4
 * Add available dimensions for PdfPageFormat
 * Add Document properties

@@ -17,13 +17,17 @@
 part of pdf;
 
 class PdfColor {
-  const PdfColor(this.r, this.g, this.b, [this.a = 1.0]);
+  const PdfColor(this.red, this.green, this.blue, [this.alpha = 1.0])
+      : assert(red >= 0 && red <= 1),
+        assert(green >= 0 && green <= 1),
+        assert(blue >= 0 && blue <= 1),
+        assert(alpha >= 0 && alpha <= 1);
 
   const PdfColor.fromInt(int color)
-      : r = (color >> 16 & 0xff) / 255.0,
-        g = (color >> 8 & 0xff) / 255.0,
-        b = (color & 0xff) / 255.0,
-        a = (color >> 24 & 0xff) / 255.0;
+      : red = (color >> 16 & 0xff) / 255.0,
+        green = (color >> 8 & 0xff) / 255.0,
+        blue = (color & 0xff) / 255.0,
+        alpha = (color >> 24 & 0xff) / 255.0;
 
   factory PdfColor.fromHex(String color) {
     if (color.startsWith('#')) {
@@ -36,73 +40,30 @@ class PdfColor {
         (int.parse(color.substring(6, 7), radix: 16) >> 24 & 0xff) / 255.0);
   }
 
-  final double a;
-  final double r;
-  final double g;
-  final double b;
-
-  @deprecated
-  static const PdfColor black = PdfColors.black;
-  @deprecated
-  static const PdfColor white = PdfColors.white;
-  @deprecated
-  static const PdfColor red = PdfColors.red;
-  @deprecated
-  static const PdfColor pink = PdfColors.pink;
-  @deprecated
-  static const PdfColor purple = PdfColors.purple;
-  @deprecated
-  static const PdfColor deepPurple = PdfColors.deepPurple;
-  @deprecated
-  static const PdfColor indigo = PdfColors.indigo;
-  @deprecated
-  static const PdfColor blue = PdfColors.blue;
-  @deprecated
-  static const PdfColor lightBlue = PdfColors.lightBlue;
-  @deprecated
-  static const PdfColor cyan = PdfColors.cyan;
-  @deprecated
-  static const PdfColor teal = PdfColors.teal;
-  @deprecated
-  static const PdfColor green = PdfColors.green;
-  @deprecated
-  static const PdfColor lightGreen = PdfColors.lightGreen;
-  @deprecated
-  static const PdfColor lime = PdfColors.lime;
-  @deprecated
-  static const PdfColor yellow = PdfColors.yellow;
-  @deprecated
-  static const PdfColor amber = PdfColors.amber;
-  @deprecated
-  static const PdfColor orange = PdfColors.orange;
-  @deprecated
-  static const PdfColor deepOrange = PdfColors.deepOrange;
-  @deprecated
-  static const PdfColor brown = PdfColors.brown;
-  @deprecated
-  static const PdfColor grey = PdfColors.grey;
-  @deprecated
-  static const PdfColor blueGrey = PdfColors.blueGrey;
+  final double alpha;
+  final double red;
+  final double green;
+  final double blue;
 
   int toInt() =>
-      ((((a * 255.0).round() & 0xff) << 24) |
-          (((r * 255.0).round() & 0xff) << 16) |
-          (((g * 255.0).round() & 0xff) << 8) |
-          (((b * 255.0).round() & 0xff) << 0)) &
+      ((((alpha * 255.0).round() & 0xff) << 24) |
+          (((red * 255.0).round() & 0xff) << 16) |
+          (((green * 255.0).round() & 0xff) << 8) |
+          (((blue * 255.0).round() & 0xff) << 0)) &
       0xFFFFFFFF;
 
   String toHex() => '#' + toInt().toRadixString(16);
 
   PdfColorCmyk toCmyk() {
-    return PdfColorCmyk.fromRgb(r, g, b, a);
+    return PdfColorCmyk.fromRgb(red, green, blue, alpha);
   }
 
   PdfColorHsv toHsv() {
-    return PdfColorHsv.fromRgb(r, g, b, a);
+    return PdfColorHsv.fromRgb(red, green, blue, alpha);
   }
 
   PdfColorHsl toHsl() {
-    return PdfColorHsl.fromRgb(r, g, b, a);
+    return PdfColorHsl.fromRgb(red, green, blue, alpha);
   }
 
   static double _linearizeColorComponent(double component) {
@@ -113,35 +74,50 @@ class PdfColor {
   }
 
   double get luminance {
-    final double R = _linearizeColorComponent(r);
-    final double G = _linearizeColorComponent(g);
-    final double B = _linearizeColorComponent(b);
+    final double R = _linearizeColorComponent(red);
+    final double G = _linearizeColorComponent(green);
+    final double B = _linearizeColorComponent(blue);
     return 0.2126 * R + 0.7152 * G + 0.0722 * B;
   }
 
+  /// Get a complementary color with hue shifted by -120°
+  PdfColor get complementary => toHsv().complementary;
+
+  /// Get some similar colors
+  List<PdfColor> get monochromatic => toHsv().monochromatic;
+
+  List<PdfColor> get splitcomplementary => toHsv().splitcomplementary;
+
+  List<PdfColor> get tetradic => toHsv().tetradic;
+
+  List<PdfColor> get triadic => toHsv().triadic;
+
+  List<PdfColor> get analagous => toHsv().analagous;
+
   @override
-  String toString() => '$runtimeType($r, $g, $b, $a)';
+  String toString() => '$runtimeType($red, $green, $blue, $alpha)';
 }
 
 class PdfColorCmyk extends PdfColor {
-  const PdfColorCmyk(this.c, this.m, this.y, this.k, [double a = 1.0])
-      : super((1.0 - c) * (1.0 - k), (1.0 - m) * (1.0 - k),
-            (1.0 - y) * (1.0 - k), a);
+  const PdfColorCmyk(this.cyan, this.magenta, this.yellow, this.black,
+      [double a = 1.0])
+      : super((1.0 - cyan) * (1.0 - black), (1.0 - magenta) * (1.0 - black),
+            (1.0 - yellow) * (1.0 - black), a);
 
   const PdfColorCmyk.fromRgb(double r, double g, double b, [double a = 1.0])
-      : k = 1.0 - r > g ? r : g > b ? r > g ? r : g : b,
-        c = (1.0 - r - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)) /
+      : black = 1.0 - r > g ? r : g > b ? r > g ? r : g : b,
+        cyan = (1.0 - r - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)) /
             (1.0 - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)),
-        m = (1.0 - g - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)) /
+        magenta = (1.0 - g - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)) /
             (1.0 - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)),
-        y = (1.0 - b - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)) /
+        yellow = (1.0 - b - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)) /
             (1.0 - (1.0 - r > g ? r : g > b ? r > g ? r : g : b)),
         super(r, g, b, a);
 
-  final double c;
-  final double m;
-  final double y;
-  final double k;
+  final double cyan;
+  final double magenta;
+  final double yellow;
+  final double black;
 
   @override
   PdfColorCmyk toCmyk() {
@@ -149,7 +125,7 @@ class PdfColorCmyk extends PdfColor {
   }
 
   @override
-  String toString() => '$runtimeType($c, $m, $y, $k, $a)';
+  String toString() => '$runtimeType($cyan, $magenta, $yellow, $black, $alpha)';
 }
 
 double _getHue(
@@ -170,6 +146,9 @@ double _getHue(
   return hue;
 }
 
+/// Same as HSB, Cylindrical geometries with hue, their angular dimension,
+/// starting at the red primary at 0°, passing through the green primary
+/// at 120° and the blue primary at 240°, and then wrapping back to red at 360°
 class PdfColorHsv extends PdfColor {
   factory PdfColorHsv(double hue, double saturation, double value,
       [double alpha = 1.0]) {
@@ -213,7 +192,10 @@ class PdfColorHsv extends PdfColor {
 
   const PdfColorHsv._(this.hue, this.saturation, this.value, double red,
       double green, double blue, double alpha)
-      : super(red, green, blue, alpha);
+      : assert(hue >= 0 && hue < 360),
+        assert(saturation >= 0 && saturation <= 1),
+        assert(value >= 0 && value <= 1),
+        super(red, green, blue, alpha);
 
   factory PdfColorHsv.fromRgb(double red, double green, double blue,
       [double alpha]) {
@@ -227,8 +209,13 @@ class PdfColorHsv extends PdfColor {
     return PdfColorHsv._(hue, saturation, max, red, green, blue, alpha);
   }
 
+  /// Angular position the colorspace coordinate diagram in degrees from 0° to 360°
   final double hue;
+
+  /// Saturation of the color
   final double saturation;
+
+  /// Brightness
   final double value;
 
   @override
@@ -236,8 +223,59 @@ class PdfColorHsv extends PdfColor {
     return this;
   }
 
+  /// Get a complementary color with hue shifted by -120°
+  @override
+  PdfColorHsv get complementary =>
+      PdfColorHsv((hue - 120) % 360, saturation, value, alpha);
+
+  /// Get a similar color
+  @override
+  List<PdfColorHsv> get monochromatic => <PdfColorHsv>[
+        PdfColorHsv(
+            hue,
+            (saturation > 0.5 ? saturation - 0.2 : saturation + 0.2)
+                .clamp(0, 1),
+            (value > 0.5 ? value - 0.1 : value + 0.1).clamp(0, 1)),
+        PdfColorHsv(
+            hue,
+            (saturation > 0.5 ? saturation - 0.4 : saturation + 0.4)
+                .clamp(0, 1),
+            (value > 0.5 ? value - 0.2 : value + 0.2).clamp(0, 1)),
+        PdfColorHsv(
+            hue,
+            (saturation > 0.5 ? saturation - 0.15 : saturation + 0.15)
+                .clamp(0, 1),
+            (value > 0.5 ? value - 0.05 : value + 0.05).clamp(0, 1))
+      ];
+
+  /// Get two complementary colors with hue shifted by -120°
+  @override
+  List<PdfColorHsv> get splitcomplementary => <PdfColorHsv>[
+        PdfColorHsv((hue - 150) % 360, saturation, value, alpha),
+        PdfColorHsv((hue - 180) % 360, saturation, value, alpha),
+      ];
+
+  @override
+  List<PdfColorHsv> get triadic => <PdfColorHsv>[
+        PdfColorHsv((hue + 80) % 360, saturation, value, alpha),
+        PdfColorHsv((hue - 120) % 360, saturation, value, alpha),
+      ];
+
+  @override
+  List<PdfColorHsv> get tetradic => <PdfColorHsv>[
+        PdfColorHsv((hue + 120) % 360, saturation, value, alpha),
+        PdfColorHsv((hue - 150) % 360, saturation, value, alpha),
+        PdfColorHsv((hue + 60) % 360, saturation, value, alpha),
+      ];
+
+  @override
+  List<PdfColorHsv> get analagous => <PdfColorHsv>[
+        PdfColorHsv((hue + 30) % 360, saturation, value, alpha),
+        PdfColorHsv((hue - 20) % 360, saturation, value, alpha),
+      ];
+
   @override
-  String toString() => '$runtimeType($hue, $saturation, $value, $a)';
+  String toString() => '$runtimeType($hue, $saturation, $value, $alpha)';
 }
 
 class PdfColorHsl extends PdfColor {
@@ -309,5 +347,5 @@ class PdfColorHsl extends PdfColor {
   }
 
   @override
-  String toString() => '$runtimeType($hue, $saturation, $lightness, $a)';
+  String toString() => '$runtimeType($hue, $saturation, $lightness, $alpha)';
 }

@@ -107,13 +107,59 @@ class PDFColor extends PdfColor {
 
   factory PDFColor.fromInt(int color) {
     final PdfColor c = PdfColor.fromInt(color);
-    return PDFColor(c.r, c.g, c.b, c.a);
+    return PDFColor(c.red, c.green, c.blue, c.alpha);
   }
 
   factory PDFColor.fromHex(String color) {
     final PdfColor c = PdfColor.fromHex(color);
-    return PDFColor(c.r, c.g, c.b, c.a);
+    return PDFColor(c.red, c.green, c.blue, c.alpha);
   }
+
+  @deprecated
+  static const PdfColor black = PdfColors.black;
+  @deprecated
+  static const PdfColor white = PdfColors.white;
+  @deprecated
+  static const PdfColor pink = PdfColors.pink;
+  @deprecated
+  static const PdfColor purple = PdfColors.purple;
+  @deprecated
+  static const PdfColor deepPurple = PdfColors.deepPurple;
+  @deprecated
+  static const PdfColor indigo = PdfColors.indigo;
+  @deprecated
+  static const PdfColor lightBlue = PdfColors.lightBlue;
+  @deprecated
+  static const PdfColor cyan = PdfColors.cyan;
+  @deprecated
+  static const PdfColor teal = PdfColors.teal;
+  @deprecated
+  static const PdfColor lightGreen = PdfColors.lightGreen;
+  @deprecated
+  static const PdfColor lime = PdfColors.lime;
+  @deprecated
+  static const PdfColor yellow = PdfColors.yellow;
+  @deprecated
+  static const PdfColor amber = PdfColors.amber;
+  @deprecated
+  static const PdfColor orange = PdfColors.orange;
+  @deprecated
+  static const PdfColor deepOrange = PdfColors.deepOrange;
+  @deprecated
+  static const PdfColor brown = PdfColors.brown;
+  @deprecated
+  static const PdfColor grey = PdfColors.grey;
+  @deprecated
+  static const PdfColor blueGrey = PdfColors.blueGrey;
+
+  @deprecated
+  double get r => red;
+
+  @deprecated
+  double get g => green;
+
+  @deprecated
+  double get b => blue;
 }
 
 @deprecated

@@ -212,10 +212,11 @@ class PdfGraphics {
   /// @param c Color to use
   void setFillColor(PdfColor color) {
     if (color is PdfColorCmyk) {
-      buf.putNumList(<double>[color.c, color.m, color.y, color.k]);
+      buf.putNumList(
+          <double>[color.cyan, color.magenta, color.yellow, color.black]);
       buf.putString(' k\n');
     } else {
-      buf.putNumList(<double>[color.r, color.g, color.b]);
+      buf.putNumList(<double>[color.red, color.green, color.blue]);
       buf.putString(' rg\n');
     }
   }
@@ -225,10 +226,11 @@ class PdfGraphics {
   /// @param c Color to use
   void setStrokeColor(PdfColor color) {
     if (color is PdfColorCmyk) {
-      buf.putNumList(<double>[color.c, color.m, color.y, color.k]);
+      buf.putNumList(
+          <double>[color.cyan, color.magenta, color.yellow, color.black]);
       buf.putString(' K\n');
     } else {
-      buf.putNumList(<double>[color.r, color.g, color.b]);
+      buf.putNumList(<double>[color.red, color.green, color.blue]);
       buf.putString(' RG\n');
     }
   }

@@ -4,7 +4,7 @@ description: A pdf producer for Dart. It can create pdf files for both web or fl
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/pdf
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 1.3.4
+version: 1.3.5
 
 environment:
   sdk: ">=2.1.0 <3.0.0"

@@ -44,6 +44,13 @@ class Color extends StatelessWidget {
             Text(varient ?? '', style: style),
             Padding(padding: const EdgeInsets.all(2 * PdfPageFormat.mm)),
             Text(color.toHex(), style: hexStyle),
+            Row(
+                mainAxisSize: MainAxisSize.max,
+                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+                children: color.monochromatic
+                    .map<Widget>((PdfColor color) =>
+                        Container(width: 30, height: 30, color: color))
+                    .toList())
           ],
           // )
         ));