content: /*
   * Copyright 2023 Google LLC
   *
   * 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.google.material.color.dynamiccolor;
  
  import com.google.material.color.utils.MathUtils;
  
  /**
   * A class containing a value that changes with the contrast level.
   *
   * <p>Usually represents the contrast requirements for a dynamic color on its background. The four
   * values correspond to values for contrast levels -1.0, 0.0, 0.5, and 1.0, respectively.
   */
  public final class ContrastCurve {
      /**
       * Value for contrast level -1.0
       */
      private final double low;
  
      /**
       * Value for contrast level 0.0
       */
      private final double normal;
  
      /**
       * Value for contrast level 0.5
       */
      private final double medium;
  
      /**
       * Value for contrast level 1.0
       */
      private final double high;
  
      /**
       * Creates a `ContrastCurve` object.
       *
       * @param low    Value for contrast level -1.0
       * @param normal Value for contrast level 0.0
       * @param medium Value for contrast level 0.5
       * @param high   Value for contrast level 1.0
       */
      public ContrastCurve(double low, double normal, double medium, double high) {
          this.low = low;
          this.normal = normal;
          this.medium = medium;
          this.high = high;
      }
  
      /**
       * Returns the value at a given contrast level.
       *
       * @param contrastLevel The contrast level. 0.0 is the default (normal); -1.0 is the lowest; 1.0
       *                      is the highest.
       * @return The value. For contrast ratios, a number between 1.0 and 21.0.
       */
      public double get(double contrastLevel) {
          if (contrastLevel <= -1.0) {
              return this.low;
          } else if (contrastLevel < 0.0) {
              return MathUtils.lerp(this.low, this.normal, (contrastLevel - -1));
          } else if (contrastLevel < 0.5) {
              return MathUtils.lerp(this.normal, this.medium, (contrastLevel - 0) / 0.5);
          } else if (contrastLevel < 1.0) {
              return MathUtils.lerp(this.medium, this.high, (contrastLevel - 0.5) / 0.5);
          } else {
              return this.high;
          }
      }
  }
  