commonMain.dynamiccolor.ContrastCurve.kt Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of colors-jvm Show documentation

Port of the Material You color generation algorithm for Kotlin

The newest version!

/*
 * 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
		}
	}
}