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 * Standard quantized DPI for extra-high-density screens. 66 */ 67 public static final int DENSITY_XHIGH = 320; 68 69 /** 70 * Intermediate density for screens that sit somewhere between 71 * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi). 72 * This is not a density that applications should target, instead relying 73 * on the system to scale their {@link #DENSITY_XXHIGH} assets for them. 74 */ 75 public static final int DENSITY_400 = 400; 76 77 /** 78 * Standard quantized DPI for extra-extra-high-density screens. 79 */ 80 public static final int DENSITY_XXHIGH = 480; 81 82 /** 83 * Intermediate density for screens that sit somewhere between 84 * {@link #DENSITY_XXHIGH} (480 dpi) and {@link #DENSITY_XXXHIGH} (640 dpi). 85 * This is not a density that applications should target, instead relying 86 * on the system to scale their {@link #DENSITY_XXXHIGH} assets for them. 87 */ 88 public static final int DENSITY_560 = 560; 89 90 /** 91 * Standard quantized DPI for extra-extra-extra-high-density screens. Applications 92 * should not generally worry about this density; relying on XHIGH graphics 93 * being scaled up to it should be sufficient for almost all cases. A typical 94 * use of this density would be 4K television screens -- 3840x2160, which 95 * is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH. 96 */ 97 public static final int DENSITY_XXXHIGH = 640; 98 99 /** 100 * The reference density used throughout the system. 101 */ 102 public static final int DENSITY_DEFAULT = DENSITY_MEDIUM; 103 104 /** 105 * Scaling factor to convert a density in DPI units to the density scale. 106 * @hide 107 */ 108 public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT; 109 110 /** 111 * The device's density. 112 * @hide because eventually this should be able to change while 113 * running, so shouldn't be a constant. 114 * @deprecated There is no longer a static density; you can find the 115 * density for a display in {@link #densityDpi}. 116 */ 117 @Deprecated 118 public static int DENSITY_DEVICE = getDeviceDensity(); 119 120 /** 121 * The absolute width of the display in pixels. 122 */ 123 public int widthPixels; 124 /** 125 * The absolute height of the display in pixels. 126 */ 127 public int heightPixels; 128 /** 129 * The logical density of the display. This is a scaling factor for the 130 * Density Independent Pixel unit, where one DIP is one pixel on an 131 * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen), 132 * providing the baseline of the system's display. Thus on a 160dpi screen 133 * this density value will be 1; on a 120 dpi screen it would be .75; etc. 134 * 135 * <p>This value does not exactly follow the real screen size (as given by 136 * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of 137 * the overall UI in steps based on gross changes in the display dpi. For 138 * example, a 240x320 screen will have a density of 1 even if its width is 139 * 1.8", 1.3", etc. However, if the screen resolution is increased to 140 * 320x480 but the screen size remained 1.5"x2" then the density would be 141 * increased (probably to 1.5). 142 * 143 * @see #DENSITY_DEFAULT 144 */ 145 public float density; 146 /** 147 * The screen density expressed as dots-per-inch. May be either 148 * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}. 149 */ 150 public int densityDpi; 151 /** 152 * A scaling factor for fonts displayed on the display. This is the same 153 * as {@link #density}, except that it may be adjusted in smaller 154 * increments at runtime based on a user preference for the font size. 155 */ 156 public float scaledDensity; 157 /** 158 * The exact physical pixels per inch of the screen in the X dimension. 159 */ 160 public float xdpi; 161 /** 162 * The exact physical pixels per inch of the screen in the Y dimension. 163 */ 164 public float ydpi; 165 166 /** 167 * The reported display width prior to any compatibility mode scaling 168 * being applied. 169 * @hide 170 */ 171 public int noncompatWidthPixels; 172 /** 173 * The reported display height prior to any compatibility mode scaling 174 * being applied. 175 * @hide 176 */ 177 public int noncompatHeightPixels; 178 /** 179 * The reported display density prior to any compatibility mode scaling 180 * being applied. 181 * @hide 182 */ 183 public float noncompatDensity; 184 /** 185 * The reported display density prior to any compatibility mode scaling 186 * being applied. 187 * @hide 188 */ 189 public int noncompatDensityDpi; 190 /** 191 * The reported scaled density prior to any compatibility mode scaling 192 * being applied. 193 * @hide 194 */ 195 public float noncompatScaledDensity; 196 /** 197 * The reported display xdpi prior to any compatibility mode scaling 198 * being applied. 199 * @hide 200 */ 201 public float noncompatXdpi; 202 /** 203 * The reported display ydpi prior to any compatibility mode scaling 204 * being applied. 205 * @hide 206 */ 207 public float noncompatYdpi; 208 DisplayMetrics()209 public DisplayMetrics() { 210 } 211 setTo(DisplayMetrics o)212 public void setTo(DisplayMetrics o) { 213 widthPixels = o.widthPixels; 214 heightPixels = o.heightPixels; 215 density = o.density; 216 densityDpi = o.densityDpi; 217 scaledDensity = o.scaledDensity; 218 xdpi = o.xdpi; 219 ydpi = o.ydpi; 220 noncompatWidthPixels = o.noncompatWidthPixels; 221 noncompatHeightPixels = o.noncompatHeightPixels; 222 noncompatDensity = o.noncompatDensity; 223 noncompatDensityDpi = o.noncompatDensityDpi; 224 noncompatScaledDensity = o.noncompatScaledDensity; 225 noncompatXdpi = o.noncompatXdpi; 226 noncompatYdpi = o.noncompatYdpi; 227 } 228 setToDefaults()229 public void setToDefaults() { 230 widthPixels = 0; 231 heightPixels = 0; 232 density = DENSITY_DEVICE / (float) DENSITY_DEFAULT; 233 densityDpi = DENSITY_DEVICE; 234 scaledDensity = density; 235 xdpi = DENSITY_DEVICE; 236 ydpi = DENSITY_DEVICE; 237 noncompatWidthPixels = widthPixels; 238 noncompatHeightPixels = heightPixels; 239 noncompatDensity = density; 240 noncompatDensityDpi = densityDpi; 241 noncompatScaledDensity = scaledDensity; 242 noncompatXdpi = xdpi; 243 noncompatYdpi = ydpi; 244 } 245 246 @Override equals(Object o)247 public boolean equals(Object o) { 248 return o instanceof DisplayMetrics && equals((DisplayMetrics)o); 249 } 250 251 /** 252 * Returns true if these display metrics equal the other display metrics. 253 * 254 * @param other The display metrics with which to compare. 255 * @return True if the display metrics are equal. 256 */ equals(DisplayMetrics other)257 public boolean equals(DisplayMetrics other) { 258 return equalsPhysical(other) 259 && scaledDensity == other.scaledDensity 260 && noncompatScaledDensity == other.noncompatScaledDensity; 261 } 262 263 /** 264 * Returns true if the physical aspects of the two display metrics 265 * are equal. This ignores the scaled density, which is a logical 266 * attribute based on the current desired font size. 267 * 268 * @param other The display metrics with which to compare. 269 * @return True if the display metrics are equal. 270 * @hide 271 */ equalsPhysical(DisplayMetrics other)272 public boolean equalsPhysical(DisplayMetrics other) { 273 return other != null 274 && widthPixels == other.widthPixels 275 && heightPixels == other.heightPixels 276 && density == other.density 277 && densityDpi == other.densityDpi 278 && xdpi == other.xdpi 279 && ydpi == other.ydpi 280 && noncompatWidthPixels == other.noncompatWidthPixels 281 && noncompatHeightPixels == other.noncompatHeightPixels 282 && noncompatDensity == other.noncompatDensity 283 && noncompatDensityDpi == other.noncompatDensityDpi 284 && noncompatXdpi == other.noncompatXdpi 285 && noncompatYdpi == other.noncompatYdpi; 286 } 287 288 @Override hashCode()289 public int hashCode() { 290 return widthPixels * heightPixels * densityDpi; 291 } 292 293 @Override toString()294 public String toString() { 295 return "DisplayMetrics{density=" + density + ", width=" + widthPixels + 296 ", height=" + heightPixels + ", scaledDensity=" + scaledDensity + 297 ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}"; 298 } 299 getDeviceDensity()300 private static int getDeviceDensity() { 301 // qemu.sf.lcd_density can be used to override ro.sf.lcd_density 302 // when running in the emulator, allowing for dynamic configurations. 303 // The reason for this is that ro.sf.lcd_density is write-once and is 304 // set by the init process when it parses build.prop before anything else. 305 return SystemProperties.getInt("qemu.sf.lcd_density", 306 SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT)); 307 } 308 } 309