1 /* 2 * Copyright (C) 2006 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 19 import android.os.SystemProperties; 20 21 22 /** 23 * A structure describing general information about a display, such as its 24 * size, density, and font scaling. 25 * <p>To access the DisplayMetrics members, initialize an object like this:</p> 26 * <pre> DisplayMetrics metrics = new DisplayMetrics(); 27 * getWindowManager().getDefaultDisplay().getMetrics(metrics);</pre> 28 */ 29 public class DisplayMetrics { 30 /** 31 * Standard quantized DPI for low-density screens. 32 */ 33 public static final int DENSITY_LOW = 120; 34 35 /** 36 * Standard quantized DPI for medium-density screens. 37 */ 38 public static final int DENSITY_MEDIUM = 160; 39 40 /** 41 * This is a secondary density, added for some common screen configurations. 42 * It is recommended that applications not generally target this as a first 43 * class density -- that is, don't supply specific graphics for this 44 * density, instead allow the platform to scale from other densities 45 * (typically {@link #DENSITY_HIGH}) as 46 * appropriate. In most cases (such as using bitmaps in 47 * {@link android.graphics.drawable.Drawable}) the platform 48 * can perform this scaling at load time, so the only cost is some slight 49 * startup runtime overhead. 50 * 51 * <p>This density was original introduced to correspond with a 52 * 720p TV screen: the density for 1080p televisions is 53 * {@link #DENSITY_XHIGH}, and the value here provides the same UI 54 * size for a TV running at 720p. It has also found use in 7" tablets, 55 * when these devices have 1280x720 displays. 56 */ 57 public static final int DENSITY_TV = 213; 58 59 /** 60 * Standard quantized DPI for high-density screens. 61 */ 62 public static final int DENSITY_HIGH = 240; 63 64 /** 65 * Intermediate density for screens that sit between {@link #DENSITY_HIGH} (240dpi) and 66 * {@link #DENSITY_XHIGH} (320dpi). This is not a density that applications should target, 67 * instead relying on the system to scale their {@link #DENSITY_XHIGH} assets for them. 68 */ 69 public static final int DENSITY_280 = 280; 70 71 /** 72 * Standard quantized DPI for extra-high-density screens. 73 */ 74 public static final int DENSITY_XHIGH = 320; 75 76 /** 77 * Intermediate density for screens that sit somewhere between 78 * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi). 79 * This is not a density that applications should target, instead relying 80 * on the system to scale their {@link #DENSITY_XXHIGH} assets for them. 81 */ 82 public static final int DENSITY_360 = 360; 83 84 /** 85 * Intermediate density for screens that sit somewhere between 86 * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi). 87 * This is not a density that applications should target, instead relying 88 * on the system to scale their {@link #DENSITY_XXHIGH} assets for them. 89 */ 90 public static final int DENSITY_400 = 400; 91 92 /** 93 * Intermediate density for screens that sit somewhere between 94 * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi). 95 * This is not a density that applications should target, instead relying 96 * on the system to scale their {@link #DENSITY_XXHIGH} assets for them. 97 */ 98 public static final int DENSITY_420 = 420; 99 100 /** 101 * Standard quantized DPI for extra-extra-high-density screens. 102 */ 103 public static final int DENSITY_XXHIGH = 480; 104 105 /** 106 * Intermediate density for screens that sit somewhere between 107 * {@link #DENSITY_XXHIGH} (480 dpi) and {@link #DENSITY_XXXHIGH} (640 dpi). 108 * This is not a density that applications should target, instead relying 109 * on the system to scale their {@link #DENSITY_XXXHIGH} assets for them. 110 */ 111 public static final int DENSITY_560 = 560; 112 113 /** 114 * Standard quantized DPI for extra-extra-extra-high-density screens. Applications 115 * should not generally worry about this density; relying on XHIGH graphics 116 * being scaled up to it should be sufficient for almost all cases. A typical 117 * use of this density would be 4K television screens -- 3840x2160, which 118 * is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH. 119 */ 120 public static final int DENSITY_XXXHIGH = 640; 121 122 /** 123 * The reference density used throughout the system. 124 */ 125 public static final int DENSITY_DEFAULT = DENSITY_MEDIUM; 126 127 /** 128 * Scaling factor to convert a density in DPI units to the density scale. 129 * @hide 130 */ 131 public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT; 132 133 /** 134 * The device's density. 135 * @hide because eventually this should be able to change while 136 * running, so shouldn't be a constant. 137 * @deprecated There is no longer a static density; you can find the 138 * density for a display in {@link #densityDpi}. 139 */ 140 @Deprecated 141 public static int DENSITY_DEVICE = getDeviceDensity(); 142 143 /** 144 * The absolute width of the display in pixels. 145 */ 146 public int widthPixels; 147 /** 148 * The absolute height of the display in pixels. 149 */ 150 public int heightPixels; 151 /** 152 * The logical density of the display. This is a scaling factor for the 153 * Density Independent Pixel unit, where one DIP is one pixel on an 154 * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen), 155 * providing the baseline of the system's display. Thus on a 160dpi screen 156 * this density value will be 1; on a 120 dpi screen it would be .75; etc. 157 * 158 * <p>This value does not exactly follow the real screen size (as given by 159 * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of 160 * the overall UI in steps based on gross changes in the display dpi. For 161 * example, a 240x320 screen will have a density of 1 even if its width is 162 * 1.8", 1.3", etc. However, if the screen resolution is increased to 163 * 320x480 but the screen size remained 1.5"x2" then the density would be 164 * increased (probably to 1.5). 165 * 166 * @see #DENSITY_DEFAULT 167 */ 168 public float density; 169 /** 170 * The screen density expressed as dots-per-inch. May be either 171 * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}. 172 */ 173 public int densityDpi; 174 /** 175 * A scaling factor for fonts displayed on the display. This is the same 176 * as {@link #density}, except that it may be adjusted in smaller 177 * increments at runtime based on a user preference for the font size. 178 */ 179 public float scaledDensity; 180 /** 181 * The exact physical pixels per inch of the screen in the X dimension. 182 */ 183 public float xdpi; 184 /** 185 * The exact physical pixels per inch of the screen in the Y dimension. 186 */ 187 public float ydpi; 188 189 /** 190 * The reported display width prior to any compatibility mode scaling 191 * being applied. 192 * @hide 193 */ 194 public int noncompatWidthPixels; 195 /** 196 * The reported display height prior to any compatibility mode scaling 197 * being applied. 198 * @hide 199 */ 200 public int noncompatHeightPixels; 201 /** 202 * The reported display density prior to any compatibility mode scaling 203 * being applied. 204 * @hide 205 */ 206 public float noncompatDensity; 207 /** 208 * The reported display density prior to any compatibility mode scaling 209 * being applied. 210 * @hide 211 */ 212 public int noncompatDensityDpi; 213 /** 214 * The reported scaled density prior to any compatibility mode scaling 215 * being applied. 216 * @hide 217 */ 218 public float noncompatScaledDensity; 219 /** 220 * The reported display xdpi prior to any compatibility mode scaling 221 * being applied. 222 * @hide 223 */ 224 public float noncompatXdpi; 225 /** 226 * The reported display ydpi prior to any compatibility mode scaling 227 * being applied. 228 * @hide 229 */ 230 public float noncompatYdpi; 231 232 public DisplayMetrics() { 233 } 234 235 public void setTo(DisplayMetrics o) { 236 widthPixels = o.widthPixels; 237 heightPixels = o.heightPixels; 238 density = o.density; 239 densityDpi = o.densityDpi; 240 scaledDensity = o.scaledDensity; 241 xdpi = o.xdpi; 242 ydpi = o.ydpi; 243 noncompatWidthPixels = o.noncompatWidthPixels; 244 noncompatHeightPixels = o.noncompatHeightPixels; 245 noncompatDensity = o.noncompatDensity; 246 noncompatDensityDpi = o.noncompatDensityDpi; 247 noncompatScaledDensity = o.noncompatScaledDensity; 248 noncompatXdpi = o.noncompatXdpi; 249 noncompatYdpi = o.noncompatYdpi; 250 } 251 252 public void setToDefaults() { 253 widthPixels = 0; 254 heightPixels = 0; 255 density = DENSITY_DEVICE / (float) DENSITY_DEFAULT; 256 densityDpi = DENSITY_DEVICE; 257 scaledDensity = density; 258 xdpi = DENSITY_DEVICE; 259 ydpi = DENSITY_DEVICE; 260 noncompatWidthPixels = widthPixels; 261 noncompatHeightPixels = heightPixels; 262 noncompatDensity = density; 263 noncompatDensityDpi = densityDpi; 264 noncompatScaledDensity = scaledDensity; 265 noncompatXdpi = xdpi; 266 noncompatYdpi = ydpi; 267 } 268 269 @Override 270 public boolean equals(Object o) { 271 return o instanceof DisplayMetrics && equals((DisplayMetrics)o); 272 } 273 274 /** 275 * Returns true if these display metrics equal the other display metrics. 276 * 277 * @param other The display metrics with which to compare. 278 * @return True if the display metrics are equal. 279 */ 280 public boolean equals(DisplayMetrics other) { 281 return equalsPhysical(other) 282 && scaledDensity == other.scaledDensity 283 && noncompatScaledDensity == other.noncompatScaledDensity; 284 } 285 286 /** 287 * Returns true if the physical aspects of the two display metrics 288 * are equal. This ignores the scaled density, which is a logical 289 * attribute based on the current desired font size. 290 * 291 * @param other The display metrics with which to compare. 292 * @return True if the display metrics are equal. 293 * @hide 294 */ 295 public boolean equalsPhysical(DisplayMetrics other) { 296 return other != null 297 && widthPixels == other.widthPixels 298 && heightPixels == other.heightPixels 299 && density == other.density 300 && densityDpi == other.densityDpi 301 && xdpi == other.xdpi 302 && ydpi == other.ydpi 303 && noncompatWidthPixels == other.noncompatWidthPixels 304 && noncompatHeightPixels == other.noncompatHeightPixels 305 && noncompatDensity == other.noncompatDensity 306 && noncompatDensityDpi == other.noncompatDensityDpi 307 && noncompatXdpi == other.noncompatXdpi 308 && noncompatYdpi == other.noncompatYdpi; 309 } 310 311 @Override 312 public int hashCode() { 313 return widthPixels * heightPixels * densityDpi; 314 } 315 316 @Override 317 public String toString() { 318 return "DisplayMetrics{density=" + density + ", width=" + widthPixels + 319 ", height=" + heightPixels + ", scaledDensity=" + scaledDensity + 320 ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}"; 321 } 322 323 private static int getDeviceDensity() { 324 // qemu.sf.lcd_density can be used to override ro.sf.lcd_density 325 // when running in the emulator, allowing for dynamic configurations. 326 // The reason for this is that ro.sf.lcd_density is write-once and is 327 // set by the init process when it parses build.prop before anything else. 328 return SystemProperties.getInt("qemu.sf.lcd_density", 329 SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT)); 330 } 331 } 332
