// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.base;
/** Contains various math utilities used throughout Chrome Mobile. */
public class MathUtils {
/** A minimum difference to use when comparing floats for equality. */
public static final float EPSILON = 0.001f;
private MathUtils() {}
/**
* Returns the passed in value if it resides within the specified range (inclusive). If not,
* it will return the closest boundary from the range. The ordering of the boundary values does
* not matter.
*
* @param value The value to be compared against the range.
* @param a First boundary range value.
* @param b Second boundary range value.
* @return The passed in value if it is within the range, otherwise the closest boundary value.
*/
public static int clamp(int value, int a, int b) {
int min = (a > b) ? b : a;
int max = (a > b) ? a : b;
if (value < min) {
value = min;
} else if (value > max) {
value = max;
}
return value;
}
/**
* Returns the passed in value if it resides within the specified range (inclusive). If not,
* it will return the closest boundary from the range. The ordering of the boundary values does
* not matter.
*
* @param value The value to be compared against the range.
* @param a First boundary range value.
* @param b Second boundary range value.
* @return The passed in value if it is within the range, otherwise the closest boundary value.
*/
public static long clamp(long value, long a, long b) {
long min = (a > b) ? b : a;
long max = (a > b) ? a : b;
if (value < min) {
value = min;
} else if (value > max) {
value = max;
}
return value;
}
/**
* Returns the passed in value if it resides within the specified range (inclusive). If not,
* it will return the closest boundary from the range. The ordering of the boundary values does
* not matter.
*
* @param value The value to be compared against the range.
* @param a First boundary range value.
* @param b Second boundary range value.
* @return The passed in value if it is within the range, otherwise the closest boundary value.
*/
public static float clamp(float value, float a, float b) {
float min = (a > b) ? b : a;
float max = (a > b) ? a : b;
if (value < min) {
value = min;
} else if (value > max) {
value = max;
}
return value;
}
/**
* Computes a%b that is positive. Note that result of % operation is not always positive.
* @return a%b >= 0 ? a%b : a%b + b
*/
public static int positiveModulo(int a, int b) {
int mod = a % b;
return mod >= 0 ? mod : mod + b;
}
/**
* Moves {@code value} forward to {@code target} based on {@code speed}.
* @param value The current value.
* @param target The target value.
* @param speed How far to move {@code value} to {@code target}. 0 doesn't move it at all. 1
* moves it to {@code target}.
* @return The new interpolated value.
*/
public static float interpolate(float value, float target, float speed) {
return (value + (target - value) * speed);
}
/**
* Smooth a value between 0 and 1.
* @param t The value to smooth.
* @return The smoothed value between 0 and 1.
*/
public static float smoothstep(float t) {
return t * t * (3.0f - 2.0f * t);
}
/**
* Flips {@code value} iff {@code flipSign} is {@code true}.
* @param value The value to flip.
* @param flipSign Whether or not to flip the value.
* @return {@code value} iff {@code flipSign} is {@code false}, otherwise negative
* {@code value}.
*/
public static int flipSignIf(int value, boolean flipSign) {
return flipSign ? -value : value;
}
/**
* Flips {@code value} iff {@code flipSign} is {@code true}.
* @param value The value to flip.
* @param flipSign Whether or not to flip the value.
* @return {@code value} iff {@code flipSign} is {@code false}, otherwise negative
* {@code value}.
*/
public static float flipSignIf(float value, boolean flipSign) {
return flipSign ? -value : value;
}
/**
* Determine if two floats are equal.
* @param f1 The first float to compare.
* @param f2 The second float to compare.
* @return True if the floats are equal.
*/
public static boolean areFloatsEqual(float f1, float f2) {
return Math.abs(f1 - f2) < MathUtils.EPSILON;
}
/**
* Compute the distance between two points.
* @param x1 X of point 1.
* @param y1 Y of point 1.
* @param x2 X of point 2.
* @param y2 Y of point 2.
* @return The distance between the two points.
*/
public static float distance(float x1, float y1, float x2, float y2) {
float xDist = x2 - x1;
float yDist = y2 - y1;
return (float) Math.sqrt(xDist * xDist + yDist * yDist);
}
/**
* Compute the distance given two coordinate vectors
*/
public static float distance(float distanceX, float distanceY) {
return (float) Math.sqrt(distanceX * distanceX + distanceY * distanceY);
}
/**
* Maps {@code value} in [{@code fromStart}, {@code fromStop}] to
* [{@code toStart}, {@code toStop}].
*
* @param value A number in [{@code fromStart}, {@code fromStop}].
* @param fromStart Lower range of {@code value}.
* @param fromStop Upper range of {@code value}.
* @param toStart Lower range of mapped value.
* @param toStop Upper range of mapped value.
* @return mapped value.
*/
public static float map(
float value, float fromStart, float fromStop, float toStart, float toStop) {
return toStart + (toStop - toStart) * ((value - fromStart) / (fromStop - fromStart));
}
/**
* Round the given value to two decimal places.
*
* @param value double The value to round.
* @return double The value rounded to two decimal places.
*/
public static double roundTwoDecimalPlaces(double value) {
return (double) Math.round(value * 100) / 100;
}
}
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