Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2009 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.util; |
| 18 | |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 19 | import android.annotation.UnsupportedAppUsage; |
Lucas Dupin | ed00262 | 2018-10-25 18:12:15 -0700 | [diff] [blame] | 20 | import android.graphics.Rect; |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 21 | |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 22 | /** |
| 23 | * A class that contains utility methods related to numbers. |
ztenghui | 9af77a4c | 2015-04-01 16:38:44 -0700 | [diff] [blame] | 24 | * |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 25 | * @hide Pending API council approval |
| 26 | */ |
| 27 | public final class MathUtils { |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 28 | private static final float DEG_TO_RAD = 3.1415926f / 180.0f; |
| 29 | private static final float RAD_TO_DEG = 180.0f / 3.1415926f; |
| 30 | |
| 31 | private MathUtils() { |
| 32 | } |
| 33 | |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 34 | @UnsupportedAppUsage |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 35 | public static float abs(float v) { |
ztenghui | 9af77a4c | 2015-04-01 16:38:44 -0700 | [diff] [blame] | 36 | return v > 0 ? v : -v; |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 37 | } |
| 38 | |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 39 | @UnsupportedAppUsage |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 40 | public static int constrain(int amount, int low, int high) { |
| 41 | return amount < low ? low : (amount > high ? high : amount); |
| 42 | } |
| 43 | |
Jeff Sharkey | ac3fcb1 | 2012-05-02 18:11:52 -0700 | [diff] [blame] | 44 | public static long constrain(long amount, long low, long high) { |
| 45 | return amount < low ? low : (amount > high ? high : amount); |
| 46 | } |
| 47 | |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 48 | @UnsupportedAppUsage |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 49 | public static float constrain(float amount, float low, float high) { |
| 50 | return amount < low ? low : (amount > high ? high : amount); |
| 51 | } |
| 52 | |
| 53 | public static float log(float a) { |
| 54 | return (float) Math.log(a); |
| 55 | } |
| 56 | |
| 57 | public static float exp(float a) { |
| 58 | return (float) Math.exp(a); |
| 59 | } |
| 60 | |
| 61 | public static float pow(float a, float b) { |
| 62 | return (float) Math.pow(a, b); |
| 63 | } |
| 64 | |
Michael Wright | 585ff98 | 2018-04-13 18:15:27 +0100 | [diff] [blame] | 65 | public static float sqrt(float a) { |
| 66 | return (float) Math.sqrt(a); |
| 67 | } |
| 68 | |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 69 | public static float max(float a, float b) { |
| 70 | return a > b ? a : b; |
| 71 | } |
| 72 | |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 73 | @UnsupportedAppUsage |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 74 | public static float max(int a, int b) { |
| 75 | return a > b ? a : b; |
| 76 | } |
| 77 | |
| 78 | public static float max(float a, float b, float c) { |
| 79 | return a > b ? (a > c ? a : c) : (b > c ? b : c); |
| 80 | } |
| 81 | |
| 82 | public static float max(int a, int b, int c) { |
| 83 | return a > b ? (a > c ? a : c) : (b > c ? b : c); |
| 84 | } |
| 85 | |
| 86 | public static float min(float a, float b) { |
| 87 | return a < b ? a : b; |
| 88 | } |
| 89 | |
| 90 | public static float min(int a, int b) { |
| 91 | return a < b ? a : b; |
| 92 | } |
| 93 | |
| 94 | public static float min(float a, float b, float c) { |
| 95 | return a < b ? (a < c ? a : c) : (b < c ? b : c); |
| 96 | } |
| 97 | |
| 98 | public static float min(int a, int b, int c) { |
| 99 | return a < b ? (a < c ? a : c) : (b < c ? b : c); |
| 100 | } |
| 101 | |
| 102 | public static float dist(float x1, float y1, float x2, float y2) { |
| 103 | final float x = (x2 - x1); |
| 104 | final float y = (y2 - y1); |
Neil Fuller | 33253a4 | 2014-10-01 11:55:10 +0100 | [diff] [blame] | 105 | return (float) Math.hypot(x, y); |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 106 | } |
| 107 | |
| 108 | public static float dist(float x1, float y1, float z1, float x2, float y2, float z2) { |
| 109 | final float x = (x2 - x1); |
| 110 | final float y = (y2 - y1); |
| 111 | final float z = (z2 - z1); |
| 112 | return (float) Math.sqrt(x * x + y * y + z * z); |
| 113 | } |
| 114 | |
| 115 | public static float mag(float a, float b) { |
Neil Fuller | 33253a4 | 2014-10-01 11:55:10 +0100 | [diff] [blame] | 116 | return (float) Math.hypot(a, b); |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 117 | } |
| 118 | |
| 119 | public static float mag(float a, float b, float c) { |
| 120 | return (float) Math.sqrt(a * a + b * b + c * c); |
| 121 | } |
| 122 | |
| 123 | public static float sq(float v) { |
| 124 | return v * v; |
| 125 | } |
| 126 | |
ztenghui | 9af77a4c | 2015-04-01 16:38:44 -0700 | [diff] [blame] | 127 | public static float dot(float v1x, float v1y, float v2x, float v2y) { |
| 128 | return v1x * v2x + v1y * v2y; |
| 129 | } |
| 130 | |
| 131 | public static float cross(float v1x, float v1y, float v2x, float v2y) { |
| 132 | return v1x * v2y - v1y * v2x; |
| 133 | } |
| 134 | |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 135 | public static float radians(float degrees) { |
| 136 | return degrees * DEG_TO_RAD; |
| 137 | } |
| 138 | |
Romain Guy | a9d2d5e | 2009-08-09 17:04:54 -0700 | [diff] [blame] | 139 | public static float degrees(float radians) { |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 140 | return radians * RAD_TO_DEG; |
| 141 | } |
| 142 | |
| 143 | public static float acos(float value) { |
| 144 | return (float) Math.acos(value); |
| 145 | } |
| 146 | |
| 147 | public static float asin(float value) { |
| 148 | return (float) Math.asin(value); |
| 149 | } |
| 150 | |
| 151 | public static float atan(float value) { |
| 152 | return (float) Math.atan(value); |
| 153 | } |
| 154 | |
| 155 | public static float atan2(float a, float b) { |
| 156 | return (float) Math.atan2(a, b); |
| 157 | } |
| 158 | |
| 159 | public static float tan(float angle) { |
| 160 | return (float) Math.tan(angle); |
ztenghui | 9af77a4c | 2015-04-01 16:38:44 -0700 | [diff] [blame] | 161 | } |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 162 | |
Mathew Inwood | 4eb56ab | 2018-08-14 17:24:32 +0100 | [diff] [blame] | 163 | @UnsupportedAppUsage |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 164 | public static float lerp(float start, float stop, float amount) { |
| 165 | return start + (stop - start) * amount; |
| 166 | } |
ztenghui | 9af77a4c | 2015-04-01 16:38:44 -0700 | [diff] [blame] | 167 | |
Alan Viverette | 2b4dc11 | 2015-10-02 15:29:43 -0400 | [diff] [blame] | 168 | /** |
Zak Cohen | c730de9 | 2019-02-11 14:54:56 -0800 | [diff] [blame] | 169 | * Returns the interpolation scalar (s) that satisfies the equation: {@code value = }{@link |
| 170 | * #lerp}{@code (a, b, s)} |
| 171 | * |
| 172 | * <p>If {@code a == b}, then this function will return 0. |
| 173 | */ |
| 174 | public static float lerpInv(float a, float b, float value) { |
| 175 | return a != b ? ((value - a) / (b - a)) : 0.0f; |
| 176 | } |
| 177 | |
| 178 | /** Returns the single argument constrained between [0.0, 1.0]. */ |
| 179 | public static float saturate(float value) { |
| 180 | return constrain(value, 0.0f, 1.0f); |
| 181 | } |
| 182 | |
| 183 | /** Returns the saturated (constrained between [0, 1]) result of {@link #lerpInv}. */ |
| 184 | public static float lerpInvSat(float a, float b, float value) { |
| 185 | return saturate(lerpInv(a, b, value)); |
| 186 | } |
| 187 | |
| 188 | /** |
Alan Viverette | 2b4dc11 | 2015-10-02 15:29:43 -0400 | [diff] [blame] | 189 | * Returns an interpolated angle in degrees between a set of start and end |
| 190 | * angles. |
| 191 | * <p> |
| 192 | * Unlike {@link #lerp(float, float, float)}, the direction and distance of |
| 193 | * travel is determined by the shortest angle between the start and end |
| 194 | * angles. For example, if the starting angle is 0 and the ending angle is |
| 195 | * 350, then the interpolated angle will be in the range [0,-10] rather |
| 196 | * than [0,350]. |
| 197 | * |
| 198 | * @param start the starting angle in degrees |
| 199 | * @param end the ending angle in degrees |
| 200 | * @param amount the position between start and end in the range [0,1] |
| 201 | * where 0 is the starting angle and 1 is the ending angle |
| 202 | * @return the interpolated angle in degrees |
| 203 | */ |
| 204 | public static float lerpDeg(float start, float end, float amount) { |
| 205 | final float minAngle = (((end - start) + 180) % 360) - 180; |
| 206 | return minAngle * amount + start; |
| 207 | } |
| 208 | |
Romain Guy | e85c5aa | 2009-08-12 15:23:56 -0700 | [diff] [blame] | 209 | public static float norm(float start, float stop, float value) { |
| 210 | return (value - start) / (stop - start); |
| 211 | } |
ztenghui | 9af77a4c | 2015-04-01 16:38:44 -0700 | [diff] [blame] | 212 | |
Romain Guy | e85c5aa | 2009-08-12 15:23:56 -0700 | [diff] [blame] | 213 | public static float map(float minStart, float minStop, float maxStart, float maxStop, float value) { |
Lucas Dupin | 09c4bf8 | 2017-05-24 16:57:46 -0700 | [diff] [blame] | 214 | return maxStart + (maxStop - maxStart) * ((value - minStart) / (minStop - minStart)); |
Romain Guy | e85c5aa | 2009-08-12 15:23:56 -0700 | [diff] [blame] | 215 | } |
| 216 | |
Adam Lesinski | 1619ed4 | 2015-09-22 13:02:09 -0700 | [diff] [blame] | 217 | /** |
Zak Cohen | c730de9 | 2019-02-11 14:54:56 -0800 | [diff] [blame] | 218 | * Calculates a value in [rangeMin, rangeMax] that maps value in [valueMin, valueMax] to |
| 219 | * returnVal in [rangeMin, rangeMax]. |
| 220 | * <p> |
| 221 | * Always returns a constrained value in the range [rangeMin, rangeMax], even if value is |
| 222 | * outside [valueMin, valueMax]. |
| 223 | * <p> |
| 224 | * Eg: |
| 225 | * constrainedMap(0f, 100f, 0f, 1f, 0.5f) = 50f |
| 226 | * constrainedMap(20f, 200f, 10f, 20f, 20f) = 200f |
| 227 | * constrainedMap(20f, 200f, 10f, 20f, 50f) = 200f |
| 228 | * constrainedMap(10f, 50f, 10f, 20f, 5f) = 10f |
| 229 | * |
| 230 | * @param rangeMin minimum of the range that should be returned. |
| 231 | * @param rangeMax maximum of the range that should be returned. |
| 232 | * @param valueMin minimum of range to map {@code value} to. |
| 233 | * @param valueMax maximum of range to map {@code value} to. |
| 234 | * @param value to map to the range [{@code valueMin}, {@code valueMax}]. Note, can be outside |
| 235 | * this range, resulting in a clamped value. |
| 236 | * @return the mapped value, constrained to [{@code rangeMin}, {@code rangeMax}. |
| 237 | */ |
| 238 | public static float constrainedMap( |
| 239 | float rangeMin, float rangeMax, float valueMin, float valueMax, float value) { |
| 240 | return lerp(rangeMin, rangeMax, lerpInvSat(valueMin, valueMax, value)); |
| 241 | } |
| 242 | |
| 243 | /** |
Lucas Dupin | f03e752 | 2018-06-25 16:21:13 -0700 | [diff] [blame] | 244 | * Perform Hermite interpolation between two values. |
| 245 | * Eg: |
| 246 | * smoothStep(0, 0.5f, 0.5f) = 1f |
| 247 | * smoothStep(0, 0.5f, 0.25f) = 0.5f |
| 248 | * |
| 249 | * @param start Left edge. |
| 250 | * @param end Right edge. |
| 251 | * @param x A value between {@code start} and {@code end}. |
| 252 | * @return A number between 0 and 1 representing where {@code x} is in the interpolation. |
| 253 | */ |
| 254 | public static float smoothStep(float start, float end, float x) { |
| 255 | return constrain((x - start) / (end - start), 0f, 1f); |
| 256 | } |
| 257 | |
| 258 | /** |
Adam Lesinski | 1619ed4 | 2015-09-22 13:02:09 -0700 | [diff] [blame] | 259 | * Returns the sum of the two parameters, or throws an exception if the resulting sum would |
| 260 | * cause an overflow or underflow. |
| 261 | * @throws IllegalArgumentException when overflow or underflow would occur. |
| 262 | */ |
| 263 | public static int addOrThrow(int a, int b) throws IllegalArgumentException { |
| 264 | if (b == 0) { |
| 265 | return a; |
| 266 | } |
| 267 | |
| 268 | if (b > 0 && a <= (Integer.MAX_VALUE - b)) { |
| 269 | return a + b; |
| 270 | } |
| 271 | |
| 272 | if (b < 0 && a >= (Integer.MIN_VALUE - b)) { |
| 273 | return a + b; |
| 274 | } |
| 275 | throw new IllegalArgumentException("Addition overflow: " + a + " + " + b); |
| 276 | } |
Lucas Dupin | ed00262 | 2018-10-25 18:12:15 -0700 | [diff] [blame] | 277 | |
| 278 | /** |
| 279 | * Resize a {@link Rect} so one size would be {@param largestSide}. |
| 280 | * |
| 281 | * @param outToResize Rectangle that will be resized. |
| 282 | * @param largestSide Size of the largest side. |
| 283 | */ |
| 284 | public static void fitRect(Rect outToResize, int largestSide) { |
| 285 | if (outToResize.isEmpty()) { |
| 286 | return; |
| 287 | } |
| 288 | float maxSize = Math.max(outToResize.width(), outToResize.height()); |
| 289 | outToResize.scale(largestSide / maxSize); |
| 290 | } |
Romain Guy | a32d100 | 2009-07-31 15:33:59 -0700 | [diff] [blame] | 291 | } |