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