| /* |
| * Copyright (C) 2009 The Android Open Source Project |
| * |
| * 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 android.util; |
| |
| import android.annotation.UnsupportedAppUsage; |
| import android.graphics.Rect; |
| |
| /** |
| * A class that contains utility methods related to numbers. |
| * |
| * @hide Pending API council approval |
| */ |
| public final class MathUtils { |
| private static final float DEG_TO_RAD = 3.1415926f / 180.0f; |
| private static final float RAD_TO_DEG = 180.0f / 3.1415926f; |
| |
| private MathUtils() { |
| } |
| |
| @UnsupportedAppUsage |
| public static float abs(float v) { |
| return v > 0 ? v : -v; |
| } |
| |
| @UnsupportedAppUsage |
| public static int constrain(int amount, int low, int high) { |
| return amount < low ? low : (amount > high ? high : amount); |
| } |
| |
| public static long constrain(long amount, long low, long high) { |
| return amount < low ? low : (amount > high ? high : amount); |
| } |
| |
| @UnsupportedAppUsage |
| public static float constrain(float amount, float low, float high) { |
| return amount < low ? low : (amount > high ? high : amount); |
| } |
| |
| public static float log(float a) { |
| return (float) Math.log(a); |
| } |
| |
| public static float exp(float a) { |
| return (float) Math.exp(a); |
| } |
| |
| public static float pow(float a, float b) { |
| return (float) Math.pow(a, b); |
| } |
| |
| public static float sqrt(float a) { |
| return (float) Math.sqrt(a); |
| } |
| |
| public static float max(float a, float b) { |
| return a > b ? a : b; |
| } |
| |
| @UnsupportedAppUsage |
| public static float max(int a, int b) { |
| return a > b ? a : b; |
| } |
| |
| public static float max(float a, float b, float c) { |
| return a > b ? (a > c ? a : c) : (b > c ? b : c); |
| } |
| |
| public static float max(int a, int b, int c) { |
| return a > b ? (a > c ? a : c) : (b > c ? b : c); |
| } |
| |
| public static float min(float a, float b) { |
| return a < b ? a : b; |
| } |
| |
| public static float min(int a, int b) { |
| return a < b ? a : b; |
| } |
| |
| public static float min(float a, float b, float c) { |
| return a < b ? (a < c ? a : c) : (b < c ? b : c); |
| } |
| |
| public static float min(int a, int b, int c) { |
| return a < b ? (a < c ? a : c) : (b < c ? b : c); |
| } |
| |
| public static float dist(float x1, float y1, float x2, float y2) { |
| final float x = (x2 - x1); |
| final float y = (y2 - y1); |
| return (float) Math.hypot(x, y); |
| } |
| |
| public static float dist(float x1, float y1, float z1, float x2, float y2, float z2) { |
| final float x = (x2 - x1); |
| final float y = (y2 - y1); |
| final float z = (z2 - z1); |
| return (float) Math.sqrt(x * x + y * y + z * z); |
| } |
| |
| public static float mag(float a, float b) { |
| return (float) Math.hypot(a, b); |
| } |
| |
| public static float mag(float a, float b, float c) { |
| return (float) Math.sqrt(a * a + b * b + c * c); |
| } |
| |
| public static float sq(float v) { |
| return v * v; |
| } |
| |
| public static float dot(float v1x, float v1y, float v2x, float v2y) { |
| return v1x * v2x + v1y * v2y; |
| } |
| |
| public static float cross(float v1x, float v1y, float v2x, float v2y) { |
| return v1x * v2y - v1y * v2x; |
| } |
| |
| public static float radians(float degrees) { |
| return degrees * DEG_TO_RAD; |
| } |
| |
| public static float degrees(float radians) { |
| return radians * RAD_TO_DEG; |
| } |
| |
| public static float acos(float value) { |
| return (float) Math.acos(value); |
| } |
| |
| public static float asin(float value) { |
| return (float) Math.asin(value); |
| } |
| |
| public static float atan(float value) { |
| return (float) Math.atan(value); |
| } |
| |
| public static float atan2(float a, float b) { |
| return (float) Math.atan2(a, b); |
| } |
| |
| public static float tan(float angle) { |
| return (float) Math.tan(angle); |
| } |
| |
| @UnsupportedAppUsage |
| public static float lerp(float start, float stop, float amount) { |
| return start + (stop - start) * amount; |
| } |
| |
| /** |
| * Returns an interpolated angle in degrees between a set of start and end |
| * angles. |
| * <p> |
| * Unlike {@link #lerp(float, float, float)}, the direction and distance of |
| * travel is determined by the shortest angle between the start and end |
| * angles. For example, if the starting angle is 0 and the ending angle is |
| * 350, then the interpolated angle will be in the range [0,-10] rather |
| * than [0,350]. |
| * |
| * @param start the starting angle in degrees |
| * @param end the ending angle in degrees |
| * @param amount the position between start and end in the range [0,1] |
| * where 0 is the starting angle and 1 is the ending angle |
| * @return the interpolated angle in degrees |
| */ |
| public static float lerpDeg(float start, float end, float amount) { |
| final float minAngle = (((end - start) + 180) % 360) - 180; |
| return minAngle * amount + start; |
| } |
| |
| public static float norm(float start, float stop, float value) { |
| return (value - start) / (stop - start); |
| } |
| |
| public static float map(float minStart, float minStop, float maxStart, float maxStop, float value) { |
| return maxStart + (maxStop - maxStart) * ((value - minStart) / (minStop - minStart)); |
| } |
| |
| /** |
| * Perform Hermite interpolation between two values. |
| * Eg: |
| * smoothStep(0, 0.5f, 0.5f) = 1f |
| * smoothStep(0, 0.5f, 0.25f) = 0.5f |
| * |
| * @param start Left edge. |
| * @param end Right edge. |
| * @param x A value between {@code start} and {@code end}. |
| * @return A number between 0 and 1 representing where {@code x} is in the interpolation. |
| */ |
| public static float smoothStep(float start, float end, float x) { |
| return constrain((x - start) / (end - start), 0f, 1f); |
| } |
| |
| /** |
| * Returns the sum of the two parameters, or throws an exception if the resulting sum would |
| * cause an overflow or underflow. |
| * @throws IllegalArgumentException when overflow or underflow would occur. |
| */ |
| public static int addOrThrow(int a, int b) throws IllegalArgumentException { |
| if (b == 0) { |
| return a; |
| } |
| |
| if (b > 0 && a <= (Integer.MAX_VALUE - b)) { |
| return a + b; |
| } |
| |
| if (b < 0 && a >= (Integer.MIN_VALUE - b)) { |
| return a + b; |
| } |
| throw new IllegalArgumentException("Addition overflow: " + a + " + " + b); |
| } |
| |
| /** |
| * Resize a {@link Rect} so one size would be {@param largestSide}. |
| * |
| * @param outToResize Rectangle that will be resized. |
| * @param largestSide Size of the largest side. |
| */ |
| public static void fitRect(Rect outToResize, int largestSide) { |
| if (outToResize.isEmpty()) { |
| return; |
| } |
| float maxSize = Math.max(outToResize.width(), outToResize.height()); |
| outToResize.scale(largestSide / maxSize); |
| } |
| } |