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history/012_tree4/src/main/java/com/gitee/drinkjava2/frog/util/ColorUtils.java

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+/* Copyright 2018-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
+ * OF ANY KIND, either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ */
+package com.gitee.drinkjava2.frog.util;
+
+import java.awt.Color;
+
+/**
+ * Color Utilities used in this project
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+public class ColorUtils {
+
+    private static final Color[] rainbow = new Color[]{Color.GREEN, Color.RED, Color.BLUE, Color.MAGENTA, Color.YELLOW, Color.ORANGE , Color.CYAN,Color.GRAY};
+
+    private static int nextColor = 0;
+
+    private ColorUtils() {// default private constr
+    }
+
+    public static int nextColorCode() {
+        return nextColor++;
+    }
+
+    public static Color nextRainbowColor() {// 返回下一个彩虹色
+        if (nextColor == rainbow.length)
+            nextColor = 0;
+        return rainbow[nextColor++];
+    }
+
+    public static Color colorByCode(int i) {// 数值取模后返回一个固定彩虹色
+        return rainbow[i % rainbow.length];
+    }
+
+    public static Color rainbowColor(float i) { // 根据数值大小范围，在8种彩虹色中取值
+        if (i <= 20)
+            return Color.GRAY;
+        if (i <= 30)
+            return Color.BLACK;
+        if (i <= 50)
+            return Color.RED;
+        return Color.MAGENTA;
+    }
+
+    public static Color grayColor(float f) { // 根据数值大小范围0~1000，返回一个灰度色，越大越黑
+        if (f > 1000)
+            f = 1000;
+        int i1 = 255 - (int) Math.round(f * .255);
+        int i2 = 200 - (int) Math.round(f * .200);
+        int i3 = 150 - (int) Math.round(f * .150);
+        return new Color(i1, i2, i3);
+    }
+}