commonMain.dynamiccolor.ContrastCurve.kt Maven / Gradle / Ivy
/*
* Copyright (c) 2024, Google LLC, OpenSavvy and contributors.
*
* 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 opensavvy.material3.colors.dynamiccolor
import opensavvy.material3.colors.utils.lerp
/**
* 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.
*/
class ContrastCurve
/**
* 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
*/(
/** Value for contrast level -1.0 */
private val low: Double,
/** Value for contrast level 0.0 */
private val normal: Double,
/** Value for contrast level 0.5 */
private val medium: Double,
/** Value for contrast level 1.0 */
private val high: Double,
) {
/**
* 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.
*/
fun get(contrastLevel: Double): Double {
return if (contrastLevel <= -1.0) {
low
} else if (contrastLevel < 0.0) {
lerp(this.low, this.normal, (contrastLevel - -1) / 1)
} else if (contrastLevel < 0.5) {
lerp(this.normal, this.medium, (contrastLevel - 0) / 0.5)
} else if (contrastLevel < 1.0) {
lerp(this.medium, this.high, (contrastLevel - 0.5) / 0.5)
} else {
high
}
}
}