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_400 = 400; 83 84 /** 85 * Standard quantized DPI for extra-extra-high-density screens. 86 */ 87 public static final int DENSITY_XXHIGH = 480; 88 89 /** 90 * Intermediate density for screens that sit somewhere between 91 * {@link #DENSITY_XXHIGH} (480 dpi) and {@link #DENSITY_XXXHIGH} (640 dpi). 92 * This is not a density that applications should target, instead relying 93 * on the system to scale their {@link #DENSITY_XXXHIGH} assets for them. 94 */ 95 public static final int DENSITY_560 = 560; 96 97 /** 98 * Standard quantized DPI for extra-extra-extra-high-density screens. Applications 99 * should not generally worry about this density; relying on XHIGH graphics 100 * being scaled up to it should be sufficient for almost all cases. A typical 101 * use of this density would be 4K television screens -- 3840x2160, which 102 * is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH. 103 */ 104 public static final int DENSITY_XXXHIGH = 640; 105 106 /** 107 * The reference density used throughout the system. 108 */ 109 public static final int DENSITY_DEFAULT = DENSITY_MEDIUM; 110 111 /** 112 * Scaling factor to convert a density in DPI units to the density scale. 113 * @hide 114 */ 115 public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT; 116 117 /** 118 * The device's density. 119 * @hide because eventually this should be able to change while 120 * running, so shouldn't be a constant. 121 * @deprecated There is no longer a static density; you can find the 122 * density for a display in {@link #densityDpi}. 123 */ 124 @Deprecated 125 public static int DENSITY_DEVICE = getDeviceDensity(); 126 127 /** 128 * The absolute width of the display in pixels. 129 */ 130 public int widthPixels; 131 /** 132 * The absolute height of the display in pixels. 133 */ 134 public int heightPixels; 135 /** 136 * The logical density of the display. This is a scaling factor for the 137 * Density Independent Pixel unit, where one DIP is one pixel on an 138 * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen), 139 * providing the baseline of the system's display. Thus on a 160dpi screen 140 * this density value will be 1; on a 120 dpi screen it would be .75; etc. 141 * 142 * <p>This value does not exactly follow the real screen size (as given by 143 * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of 144 * the overall UI in steps based on gross changes in the display dpi. For 145 * example, a 240x320 screen will have a density of 1 even if its width is 146 * 1.8", 1.3", etc. However, if the screen resolution is increased to 147 * 320x480 but the screen size remained 1.5"x2" then the density would be 148 * increased (probably to 1.5). 149 * 150 * @see #DENSITY_DEFAULT 151 */ 152 public float density; 153 /** 154 * The screen density expressed as dots-per-inch. May be either 155 * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}. 156 */ 157 public int densityDpi; 158 /** 159 * A scaling factor for fonts displayed on the display. This is the same 160 * as {@link #density}, except that it may be adjusted in smaller 161 * increments at runtime based on a user preference for the font size. 162 */ 163 public float scaledDensity; 164 /** 165 * The exact physical pixels per inch of the screen in the X dimension. 166 */ 167 public float xdpi; 168 /** 169 * The exact physical pixels per inch of the screen in the Y dimension. 170 */ 171 public float ydpi; 172 173 /** 174 * The reported display width prior to any compatibility mode scaling 175 * being applied. 176 * @hide 177 */ 178 public int noncompatWidthPixels; 179 /** 180 * The reported display height prior to any compatibility mode scaling 181 * being applied. 182 * @hide 183 */ 184 public int noncompatHeightPixels; 185 /** 186 * The reported display density prior to any compatibility mode scaling 187 * being applied. 188 * @hide 189 */ 190 public float noncompatDensity; 191 /** 192 * The reported display density prior to any compatibility mode scaling 193 * being applied. 194 * @hide 195 */ 196 public int noncompatDensityDpi; 197 /** 198 * The reported scaled density prior to any compatibility mode scaling 199 * being applied. 200 * @hide 201 */ 202 public float noncompatScaledDensity; 203 /** 204 * The reported display xdpi prior to any compatibility mode scaling 205 * being applied. 206 * @hide 207 */ 208 public float noncompatXdpi; 209 /** 210 * The reported display ydpi prior to any compatibility mode scaling 211 * being applied. 212 * @hide 213 */ 214 public float noncompatYdpi; 215 216 public DisplayMetrics() { 217 } 218 219 public void setTo(DisplayMetrics o) { 220 widthPixels = o.widthPixels; 221 heightPixels = o.heightPixels; 222 density = o.density; 223 densityDpi = o.densityDpi; 224 scaledDensity = o.scaledDensity; 225 xdpi = o.xdpi; 226 ydpi = o.ydpi; 227 noncompatWidthPixels = o.noncompatWidthPixels; 228 noncompatHeightPixels = o.noncompatHeightPixels; 229 noncompatDensity = o.noncompatDensity; 230 noncompatDensityDpi = o.noncompatDensityDpi; 231 noncompatScaledDensity = o.noncompatScaledDensity; 232 noncompatXdpi = o.noncompatXdpi; 233 noncompatYdpi = o.noncompatYdpi; 234 } 235 236 public void setToDefaults() { 237 widthPixels = 0; 238 heightPixels = 0; 239 density = DENSITY_DEVICE / (float) DENSITY_DEFAULT; 240 densityDpi = DENSITY_DEVICE; 241 scaledDensity = density; 242 xdpi = DENSITY_DEVICE; 243 ydpi = DENSITY_DEVICE; 244 noncompatWidthPixels = widthPixels; 245 noncompatHeightPixels = heightPixels; 246 noncompatDensity = density; 247 noncompatDensityDpi = densityDpi; 248 noncompatScaledDensity = scaledDensity; 249 noncompatXdpi = xdpi; 250 noncompatYdpi = ydpi; 251 } 252 253 @Override 254 public boolean equals(Object o) { 255 return o instanceof DisplayMetrics && equals((DisplayMetrics)o); 256 } 257 258 /** 259 * Returns true if these display metrics equal the other display metrics. 260 * 261 * @param other The display metrics with which to compare. 262 * @return True if the display metrics are equal. 263 */ 264 public boolean equals(DisplayMetrics other) { 265 return equalsPhysical(other) 266 && scaledDensity == other.scaledDensity 267 && noncompatScaledDensity == other.noncompatScaledDensity; 268 } 269 270 /** 271 * Returns true if the physical aspects of the two display metrics 272 * are equal. This ignores the scaled density, which is a logical 273 * attribute based on the current desired font size. 274 * 275 * @param other The display metrics with which to compare. 276 * @return True if the display metrics are equal. 277 * @hide 278 */ 279 public boolean equalsPhysical(DisplayMetrics other) { 280 return other != null 281 && widthPixels == other.widthPixels 282 && heightPixels == other.heightPixels 283 && density == other.density 284 && densityDpi == other.densityDpi 285 && xdpi == other.xdpi 286 && ydpi == other.ydpi 287 && noncompatWidthPixels == other.noncompatWidthPixels 288 && noncompatHeightPixels == other.noncompatHeightPixels 289 && noncompatDensity == other.noncompatDensity 290 && noncompatDensityDpi == other.noncompatDensityDpi 291 && noncompatXdpi == other.noncompatXdpi 292 && noncompatYdpi == other.noncompatYdpi; 293 } 294 295 @Override 296 public int hashCode() { 297 return widthPixels * heightPixels * densityDpi; 298 } 299 300 @Override 301 public String toString() { 302 return "DisplayMetrics{density=" + density + ", width=" + widthPixels + 303 ", height=" + heightPixels + ", scaledDensity=" + scaledDensity + 304 ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}"; 305 } 306 307 private static int getDeviceDensity() { 308 // qemu.sf.lcd_density can be used to override ro.sf.lcd_density 309 // when running in the emulator, allowing for dynamic configurations. 310 // The reason for this is that ro.sf.lcd_density is write-once and is 311 // set by the init process when it parses build.prop before anything else. 312 return SystemProperties.getInt("qemu.sf.lcd_density", 313 SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT)); 314 } 315 } 316
