dynamiccolor.ContrastCurve Maven / Gradle / Ivy
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/*
* 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 dynamiccolor;
import utils.MathUtils;
/**
* A class containing a value that changes with the contrast level.
*
* 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) / 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;
}
}
}