commonMain.utils.MathUtils.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.utils
import kotlin.math.PI
import kotlin.math.abs
/**
* The signum function.
*
* @return 1 if num > 0, -1 if num < 0, and 0 if num = 0
*/
internal fun signum(num: Double): Int {
return if (num < 0) {
-1
} else if (num == 0.0) {
0
} else {
1
}
}
/**
* The linear interpolation function.
*
* @return start if amount = 0 and stop if amount = 1
*/
internal fun lerp(start: Double, stop: Double, amount: Double): Double {
return (1.0 - amount) * start + amount * stop
}
/**
* Clamps an integer between two integers.
*
* @return input when min <= input <= max, and either min or max otherwise.
*/
internal fun clampInt(min: Int, max: Int, input: Int): Int {
if (input < min) {
return min
} else if (input > max) {
return max
}
return input
}
/**
* Clamps an integer between two floating-point numbers.
*
* @return input when min <= input <= max, and either min or max otherwise.
*/
internal fun clampDouble(min: Double, max: Double, input: Double): Double {
if (input < min) {
return min
} else if (input > max) {
return max
}
return input
}
/**
* Sanitizes a degree measure as an integer.
*
* @return a degree measure between 0 (inclusive) and 360 (exclusive).
*/
internal fun sanitizeDegreesInt(degrees: Int): Int {
var degrees = degrees
degrees %= 360
if (degrees < 0) {
degrees += 360
}
return degrees
}
/**
* Sanitizes a degree measure as a floating-point number.
*
* @return a degree measure between 0.0 (inclusive) and 360.0 (exclusive).
*/
internal fun sanitizeDegreesDouble(degrees: Double): Double {
var degrees = degrees
degrees %= 360.0
if (degrees < 0) {
degrees += 360.0
}
return degrees
}
/**
* Sign of direction change needed to travel from one angle to another.
*
*
* For angles that are 180 degrees apart from each other, both directions have the same travel
* distance, so either direction is shortest. The value 1.0 is returned in this case.
*
* @param from The angle travel starts from, in degrees.
* @param to The angle travel ends at, in degrees.
* @return -1 if decreasing from leads to the shortest travel distance, 1 if increasing from leads
* to the shortest travel distance.
*/
internal fun rotationDirection(from: Double, to: Double): Double {
val increasingDifference = sanitizeDegreesDouble(to - from)
return if (increasingDifference <= 180.0) 1.0 else -1.0
}
/** Distance of two points on a circle, represented using degrees. */
internal fun differenceDegrees(a: Double, b: Double): Double {
return 180.0 - abs(abs(a - b) - 180.0)
}
/** Multiplies a 1x3 row vector with a 3x3 matrix. */
internal fun matrixMultiply(row: DoubleArray, matrix: Array): DoubleArray {
val a = row[0] * matrix[0][0] + row[1] * matrix[0][1] + row[2] * matrix[0][2]
val b = row[0] * matrix[1][0] + row[1] * matrix[1][1] + row[2] * matrix[1][2]
val c = row[0] * matrix[2][0] + row[1] * matrix[2][1] + row[2] * matrix[2][2]
return doubleArrayOf(a, b, c)
}
/**
* Convert degrees to radians.
*/
internal fun Double.toRadians() = this * PI / 180.0
/**
* Convert radians to degrees.
*/
internal fun Double.toDegrees() = this * 180.0 / PI