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 * The device's density. 83 * @hide becase eventually this should be able to change while 84 * running, so shouldn't be a constant. 85 */ 86 public static final int DENSITY_DEVICE = getDeviceDensity(); 87 88 /** 89 * The absolute width of the display in pixels. 90 */ 91 public int widthPixels; 92 /** 93 * The absolute height of the display in pixels. 94 */ 95 public int heightPixels; 96 /** 97 * The logical density of the display. This is a scaling factor for the 98 * Density Independent Pixel unit, where one DIP is one pixel on an 99 * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen), 100 * providing the baseline of the system's display. Thus on a 160dpi screen 101 * this density value will be 1; on a 120 dpi screen it would be .75; etc. 102 * 103 * <p>This value does not exactly follow the real screen size (as given by 104 * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of 105 * the overall UI in steps based on gross changes in the display dpi. For 106 * example, a 240x320 screen will have a density of 1 even if its width is 107 * 1.8", 1.3", etc. However, if the screen resolution is increased to 108 * 320x480 but the screen size remained 1.5"x2" then the density would be 109 * increased (probably to 1.5). 110 * 111 * @see #DENSITY_DEFAULT 112 */ 113 public float density; 114 /** 115 * The screen density expressed as dots-per-inch. May be either 116 * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}. 117 */ 118 public int densityDpi; 119 /** 120 * A scaling factor for fonts displayed on the display. This is the same 121 * as {@link #density}, except that it may be adjusted in smaller 122 * increments at runtime based on a user preference for the font size. 123 */ 124 public float scaledDensity; 125 /** 126 * The exact physical pixels per inch of the screen in the X dimension. 127 */ 128 public float xdpi; 129 /** 130 * The exact physical pixels per inch of the screen in the Y dimension. 131 */ 132 public float ydpi; 133 134 /** 135 * The reported display width prior to any compatibility mode scaling 136 * being applied. 137 * @hide 138 */ 139 public int noncompatWidthPixels; 140 /** 141 * The reported display height prior to any compatibility mode scaling 142 * being applied. 143 * @hide 144 */ 145 public int noncompatHeightPixels; 146 /** 147 * The reported display density prior to any compatibility mode scaling 148 * being applied. 149 * @hide 150 */ 151 public float noncompatDensity; 152 /** 153 * The reported scaled density prior to any compatibility mode scaling 154 * being applied. 155 * @hide 156 */ 157 public float noncompatScaledDensity; 158 /** 159 * The reported display xdpi prior to any compatibility mode scaling 160 * being applied. 161 * @hide 162 */ 163 public float noncompatXdpi; 164 /** 165 * The reported display ydpi prior to any compatibility mode scaling 166 * being applied. 167 * @hide 168 */ 169 public float noncompatYdpi; 170 171 public DisplayMetrics() { 172 } 173 174 public void setTo(DisplayMetrics o) { 175 widthPixels = o.widthPixels; 176 heightPixels = o.heightPixels; 177 density = o.density; 178 densityDpi = o.densityDpi; 179 scaledDensity = o.scaledDensity; 180 xdpi = o.xdpi; 181 ydpi = o.ydpi; 182 noncompatWidthPixels = o.noncompatWidthPixels; 183 noncompatHeightPixels = o.noncompatHeightPixels; 184 noncompatDensity = o.noncompatDensity; 185 noncompatScaledDensity = o.noncompatScaledDensity; 186 noncompatXdpi = o.noncompatXdpi; 187 noncompatYdpi = o.noncompatYdpi; 188 } 189 190 public void setToDefaults() { 191 widthPixels = 0; 192 heightPixels = 0; 193 density = DENSITY_DEVICE / (float) DENSITY_DEFAULT; 194 densityDpi = DENSITY_DEVICE; 195 scaledDensity = density; 196 xdpi = DENSITY_DEVICE; 197 ydpi = DENSITY_DEVICE; 198 noncompatWidthPixels = 0; 199 noncompatHeightPixels = 0; 200 } 201 202 @Override 203 public String toString() { 204 return "DisplayMetrics{density=" + density + ", width=" + widthPixels + 205 ", height=" + heightPixels + ", scaledDensity=" + scaledDensity + 206 ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}"; 207 } 208 209 private static int getDeviceDensity() { 210 // qemu.sf.lcd_density can be used to override ro.sf.lcd_density 211 // when running in the emulator, allowing for dynamic configurations. 212 // The reason for this is that ro.sf.lcd_density is write-once and is 213 // set by the init process when it parses build.prop before anything else. 214 return SystemProperties.getInt("qemu.sf.lcd_density", 215 SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT)); 216 } 217 } 218
