新增Color所有Api的完整示例

Author: AweiLoveAndroid

projects/flutter-demo/lib/color_test.dart

@@ -0,0 +1,128 @@
+import 'dart:ui';
+
+void main() {
+  test();
+}
+
+/// Color 类的所有 Api 完整使用示例
+void test() {
+  // 方式1：使用16进制颜色值
+  // #FFB5B5 粉红色 255 181 181
+  Color color = new Color(0xFFB5B5);
+  int red = color.red;
+  int green = color.green;
+  int blue = color.blue;
+  print("color: " +
+      "    red: " +
+      red.toString() +
+      "    green: " +
+      green.toString() +
+      "    blue: " +
+      blue.toString()); // red: 255    green: 181    blue: 181
+
+  // 前两位为透明度：不透明度（00是完全透明，FF是完全不透明）
+  Color color1 = new Color(0xFFFFB5B5);
+  int alpha1 = color1.alpha;
+  int red1 = color1.red;
+  int green1 = color1.green;
+  int blue1 = color1.blue;
+  print("color1: " +
+      "    alpha: " +
+      alpha1.toString() +
+      "    red: " +
+      red1.toString() +
+      "    green: " +
+      green1.toString() +
+      "    blue: " +
+      blue1.toString()); // alpha: 255    red: 255    green: 181    blue: 181
+
+  // 方式2：  参数4为：不透明度（0是完全透明，255是完全不透明）
+  Color color2 = Color.fromARGB(255, 255, 181, 181);
+  int alpha2 = color2.alpha;
+  int red2 = color2.red;
+  int green2 = color2.green;
+  int blue2 = color2.blue;
+  print("color2: " +
+      "    alpha: " +
+      alpha1.toString() +
+      "    red: " +
+      red2.toString() +
+      "    green: " +
+      green2.toString() +
+      "    blue: " +
+      blue2.toString()); // alpha: 255    red: 255    green: 181    blue: 181
+
+  // 方式3： 参数4为：不透明度（0.0是完全透明，1.0是完全不透明）
+  Color color3 = Color.fromRGBO(255, 181, 181, 1.0);
+  int red3 = color3.red;
+  int green3 = color3.green;
+  int blue3 = color3.blue;
+  double opacity3 = color3.opacity;
+  print("color3: " +
+      "    red: " +
+      red3.toString() +
+      "    green: " +
+      green3.toString() +
+      "    blue: " +
+      blue3.toString() +
+      "    " +
+      opacity3.toString()); //  red: 255    green: 181    blue: 181    1.0
+
+  // 方式4： 参数3：从0.0到1.0
+  // 算法：a + (b - a) * t
+  // 从红色到蓝色，线性插值系数为0.5
+  Color color4 = Color.lerp(new Color(0x88FF0000), new Color(0x880000FF), 0.5);
+  int alpha4 = color4.alpha;
+  int red4 = color4.red;
+  int green4 = color4.green;
+  int blue4 = color4.blue;
+  double opacity4 = color4.opacity;
+  print("color4: " +
+      "    alpha: " +
+      alpha4.toString() +
+      "    red: " +
+      red4.toString() +
+      "    green: " +
+      green4.toString() +
+      "    blue: " +
+      blue4.toString() +
+      "    opacity:" +
+      opacity4
+          .toString()); // alpha: 136    red: 127    green: 0    blue: 127    opacity:0.5333333333333333
+
+  // 方式5：把前景色作为透明色盖在背景色上面
+  Color color5 = Color.alphaBlend(new Color(0x88FF0000), new Color(0x880000FF));
+  int alpha5 = color5.alpha;
+  int red5 = color5.red;
+  int green5 = color5.green;
+  int blue5 = color5.blue;
+  double opacity5 = color4.opacity;
+  print("color5: " +
+      "    alpha: " +
+      alpha5.toString() +
+      "    red: " +
+      red5.toString() +
+      "    green: " +
+      green5.toString() +
+      "    blue: " +
+      blue5.toString() +
+      "    opacity:" +
+      opacity5
+          .toString()); // alpha: 199    red: 174    green: 0    blue: 80    opacity:0.5333333333333333
+
+  // 颜色的亮度 0是最暗，1是最亮
+  Color color6 = new Color(0x88FF0000);
+  double computeLuminance = color.computeLuminance();
+  print("color6: " + computeLuminance.toString()); // 0.5764394295278801
+
+  // 替换掉原来颜色中的 alpha 值
+  color6.withAlpha(100);
+  // 替换掉原来颜色中的 red 值
+  color6.withRed(100);
+  // 替换掉原来颜色中的 green 值
+  color6.withGreen(100);
+  // 替换掉原来颜色中的 blue 值
+  color6.withBlue(100);
+  // 替换掉原来颜色中的 opacity 值
+  color6.withOpacity(0.8);
+}