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
17package android.util;
18
19import 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 */
29public 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} (320dpi) 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.  Applications
79     * should not generally worry about this density; relying on XHIGH graphics
80     * being scaled up to it should be sufficient for almost all cases.
81     */
82    public static final int DENSITY_XXHIGH = 480;
83
84    /**
85     * Standard quantized DPI for extra-extra-extra-high-density screens.  Applications
86     * should not generally worry about this density; relying on XHIGH graphics
87     * being scaled up to it should be sufficient for almost all cases.  A typical
88     * use of this density would be 4K television screens -- 3840x2160, which
89     * is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH.
90     */
91    public static final int DENSITY_XXXHIGH = 640;
92
93    /**
94     * The reference density used throughout the system.
95     */
96    public static final int DENSITY_DEFAULT = DENSITY_MEDIUM;
97
98    /**
99     * Scaling factor to convert a density in DPI units to the density scale.
100     * @hide
101     */
102    public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT;
103
104    /**
105     * The device's density.
106     * @hide because eventually this should be able to change while
107     * running, so shouldn't be a constant.
108     * @deprecated There is no longer a static density; you can find the
109     * density for a display in {@link #densityDpi}.
110     */
111    @Deprecated
112    public static int DENSITY_DEVICE = getDeviceDensity();
113
114    /**
115     * The absolute width of the display in pixels.
116     */
117    public int widthPixels;
118    /**
119     * The absolute height of the display in pixels.
120     */
121    public int heightPixels;
122    /**
123     * The logical density of the display.  This is a scaling factor for the
124     * Density Independent Pixel unit, where one DIP is one pixel on an
125     * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen),
126     * providing the baseline of the system's display. Thus on a 160dpi screen
127     * this density value will be 1; on a 120 dpi screen it would be .75; etc.
128     *
129     * <p>This value does not exactly follow the real screen size (as given by
130     * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of
131     * the overall UI in steps based on gross changes in the display dpi.  For
132     * example, a 240x320 screen will have a density of 1 even if its width is
133     * 1.8", 1.3", etc. However, if the screen resolution is increased to
134     * 320x480 but the screen size remained 1.5"x2" then the density would be
135     * increased (probably to 1.5).
136     *
137     * @see #DENSITY_DEFAULT
138     */
139    public float density;
140    /**
141     * The screen density expressed as dots-per-inch.  May be either
142     * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}.
143     */
144    public int densityDpi;
145    /**
146     * A scaling factor for fonts displayed on the display.  This is the same
147     * as {@link #density}, except that it may be adjusted in smaller
148     * increments at runtime based on a user preference for the font size.
149     */
150    public float scaledDensity;
151    /**
152     * The exact physical pixels per inch of the screen in the X dimension.
153     */
154    public float xdpi;
155    /**
156     * The exact physical pixels per inch of the screen in the Y dimension.
157     */
158    public float ydpi;
159
160    /**
161     * The reported display width prior to any compatibility mode scaling
162     * being applied.
163     * @hide
164     */
165    public int noncompatWidthPixels;
166    /**
167     * The reported display height prior to any compatibility mode scaling
168     * being applied.
169     * @hide
170     */
171    public int noncompatHeightPixels;
172    /**
173     * The reported display density prior to any compatibility mode scaling
174     * being applied.
175     * @hide
176     */
177    public float noncompatDensity;
178    /**
179     * The reported display density prior to any compatibility mode scaling
180     * being applied.
181     * @hide
182     */
183    public int noncompatDensityDpi;
184    /**
185     * The reported scaled density prior to any compatibility mode scaling
186     * being applied.
187     * @hide
188     */
189    public float noncompatScaledDensity;
190    /**
191     * The reported display xdpi prior to any compatibility mode scaling
192     * being applied.
193     * @hide
194     */
195    public float noncompatXdpi;
196    /**
197     * The reported display ydpi prior to any compatibility mode scaling
198     * being applied.
199     * @hide
200     */
201    public float noncompatYdpi;
202
203    public DisplayMetrics() {
204    }
205
206    public void setTo(DisplayMetrics o) {
207        widthPixels = o.widthPixels;
208        heightPixels = o.heightPixels;
209        density = o.density;
210        densityDpi = o.densityDpi;
211        scaledDensity = o.scaledDensity;
212        xdpi = o.xdpi;
213        ydpi = o.ydpi;
214        noncompatWidthPixels = o.noncompatWidthPixels;
215        noncompatHeightPixels = o.noncompatHeightPixels;
216        noncompatDensity = o.noncompatDensity;
217        noncompatDensityDpi = o.noncompatDensityDpi;
218        noncompatScaledDensity = o.noncompatScaledDensity;
219        noncompatXdpi = o.noncompatXdpi;
220        noncompatYdpi = o.noncompatYdpi;
221    }
222
223    public void setToDefaults() {
224        widthPixels = 0;
225        heightPixels = 0;
226        density =  DENSITY_DEVICE / (float) DENSITY_DEFAULT;
227        densityDpi =  DENSITY_DEVICE;
228        scaledDensity = density;
229        xdpi = DENSITY_DEVICE;
230        ydpi = DENSITY_DEVICE;
231        noncompatWidthPixels = widthPixels;
232        noncompatHeightPixels = heightPixels;
233        noncompatDensity = density;
234        noncompatDensityDpi = densityDpi;
235        noncompatScaledDensity = scaledDensity;
236        noncompatXdpi = xdpi;
237        noncompatYdpi = ydpi;
238    }
239
240    @Override
241    public boolean equals(Object o) {
242        return o instanceof DisplayMetrics && equals((DisplayMetrics)o);
243    }
244
245    /**
246     * Returns true if these display metrics equal the other display metrics.
247     *
248     * @param other The display metrics with which to compare.
249     * @return True if the display metrics are equal.
250     */
251    public boolean equals(DisplayMetrics other) {
252        return equalsPhysical(other)
253                && scaledDensity == other.scaledDensity
254                && noncompatScaledDensity == other.noncompatScaledDensity;
255    }
256
257    /**
258     * Returns true if the physical aspects of the two display metrics
259     * are equal.  This ignores the scaled density, which is a logical
260     * attribute based on the current desired font size.
261     *
262     * @param other The display metrics with which to compare.
263     * @return True if the display metrics are equal.
264     * @hide
265     */
266    public boolean equalsPhysical(DisplayMetrics other) {
267        return other != null
268                && widthPixels == other.widthPixels
269                && heightPixels == other.heightPixels
270                && density == other.density
271                && densityDpi == other.densityDpi
272                && xdpi == other.xdpi
273                && ydpi == other.ydpi
274                && noncompatWidthPixels == other.noncompatWidthPixels
275                && noncompatHeightPixels == other.noncompatHeightPixels
276                && noncompatDensity == other.noncompatDensity
277                && noncompatDensityDpi == other.noncompatDensityDpi
278                && noncompatXdpi == other.noncompatXdpi
279                && noncompatYdpi == other.noncompatYdpi;
280    }
281
282    @Override
283    public int hashCode() {
284        return widthPixels * heightPixels * densityDpi;
285    }
286
287    @Override
288    public String toString() {
289        return "DisplayMetrics{density=" + density + ", width=" + widthPixels +
290            ", height=" + heightPixels + ", scaledDensity=" + scaledDensity +
291            ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}";
292    }
293
294    private static int getDeviceDensity() {
295        // qemu.sf.lcd_density can be used to override ro.sf.lcd_density
296        // when running in the emulator, allowing for dynamic configurations.
297        // The reason for this is that ro.sf.lcd_density is write-once and is
298        // set by the init process when it parses build.prop before anything else.
299        return SystemProperties.getInt("qemu.sf.lcd_density",
300                SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT));
301    }
302}
303