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 * Standard quantized DPI for 720p TV screens. Applications should 42 * generally not worry about this density, instead targeting 43 * {@link #DENSITY_XHIGH} for 1080p TV screens. For situations where 44 * output is needed for a 720p screen, the UI elements can be scaled 45 * automatically by the platform. 46 */ 47 public static final int DENSITY_TV = 213; 48 49 /** 50 * Standard quantized DPI for high-density screens. 51 */ 52 public static final int DENSITY_HIGH = 240; 53 54 /** 55 * Standard quantized DPI for extra-high-density screens. 56 */ 57 public static final int DENSITY_XHIGH = 320; 58 59 /** 60 * The reference density used throughout the system. 61 */ 62 public static final int DENSITY_DEFAULT = DENSITY_MEDIUM; 63 64 /** 65 * The device's density. 66 * @hide becase eventually this should be able to change while 67 * running, so shouldn't be a constant. 68 */ 69 public static final int DENSITY_DEVICE = getDeviceDensity(); 70 71 /** 72 * The absolute width of the display in pixels. 73 */ 74 public int widthPixels; 75 /** 76 * The absolute height of the display in pixels. 77 */ 78 public int heightPixels; 79 /** 80 * The logical density of the display. This is a scaling factor for the 81 * Density Independent Pixel unit, where one DIP is one pixel on an 82 * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen), 83 * providing the baseline of the system's display. Thus on a 160dpi screen 84 * this density value will be 1; on a 120 dpi screen it would be .75; etc. 85 * 86 * <p>This value does not exactly follow the real screen size (as given by 87 * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of 88 * the overall UI in steps based on gross changes in the display dpi. For 89 * example, a 240x320 screen will have a density of 1 even if its width is 90 * 1.8", 1.3", etc. However, if the screen resolution is increased to 91 * 320x480 but the screen size remained 1.5"x2" then the density would be 92 * increased (probably to 1.5). 93 * 94 * @see #DENSITY_DEFAULT 95 */ 96 public float density; 97 /** 98 * The screen density expressed as dots-per-inch. May be either 99 * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}. 100 */ 101 public int densityDpi; 102 /** 103 * A scaling factor for fonts displayed on the display. This is the same 104 * as {@link #density}, except that it may be adjusted in smaller 105 * increments at runtime based on a user preference for the font size. 106 */ 107 public float scaledDensity; 108 /** 109 * The exact physical pixels per inch of the screen in the X dimension. 110 */ 111 public float xdpi; 112 /** 113 * The exact physical pixels per inch of the screen in the Y dimension. 114 */ 115 public float ydpi; 116 117 /** 118 * The reported display width prior to any compatibility mode scaling 119 * being applied. 120 * @hide 121 */ 122 public int noncompatWidthPixels; 123 /** 124 * The reported display height prior to any compatibility mode scaling 125 * being applied. 126 * @hide 127 */ 128 public int noncompatHeightPixels; 129 /** 130 * The reported display density prior to any compatibility mode scaling 131 * being applied. 132 * @hide 133 */ 134 public float noncompatDensity; 135 /** 136 * The reported scaled density prior to any compatibility mode scaling 137 * being applied. 138 * @hide 139 */ 140 public float noncompatScaledDensity; 141 /** 142 * The reported display xdpi prior to any compatibility mode scaling 143 * being applied. 144 * @hide 145 */ 146 public float noncompatXdpi; 147 /** 148 * The reported display ydpi prior to any compatibility mode scaling 149 * being applied. 150 * @hide 151 */ 152 public float noncompatYdpi; 153 154 public DisplayMetrics() { 155 } 156 157 public void setTo(DisplayMetrics o) { 158 widthPixels = o.widthPixels; 159 heightPixels = o.heightPixels; 160 density = o.density; 161 densityDpi = o.densityDpi; 162 scaledDensity = o.scaledDensity; 163 xdpi = o.xdpi; 164 ydpi = o.ydpi; 165 noncompatWidthPixels = o.noncompatWidthPixels; 166 noncompatHeightPixels = o.noncompatHeightPixels; 167 noncompatDensity = o.noncompatDensity; 168 noncompatScaledDensity = o.noncompatScaledDensity; 169 noncompatXdpi = o.noncompatXdpi; 170 noncompatYdpi = o.noncompatYdpi; 171 } 172 173 public void setToDefaults() { 174 widthPixels = 0; 175 heightPixels = 0; 176 density = DENSITY_DEVICE / (float) DENSITY_DEFAULT; 177 densityDpi = DENSITY_DEVICE; 178 scaledDensity = density; 179 xdpi = DENSITY_DEVICE; 180 ydpi = DENSITY_DEVICE; 181 noncompatWidthPixels = 0; 182 noncompatHeightPixels = 0; 183 } 184 185 @Override 186 public String toString() { 187 return "DisplayMetrics{density=" + density + ", width=" + widthPixels + 188 ", height=" + heightPixels + ", scaledDensity=" + scaledDensity + 189 ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}"; 190 } 191 192 private static int getDeviceDensity() { 193 // qemu.sf.lcd_density can be used to override ro.sf.lcd_density 194 // when running in the emulator, allowing for dynamic configurations. 195 // The reason for this is that ro.sf.lcd_density is write-once and is 196 // set by the init process when it parses build.prop before anything else. 197 return SystemProperties.getInt("qemu.sf.lcd_density", 198 SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT)); 199 } 200 } 201
