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     * 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_360 = 360;
83
84    /**
85     * Intermediate density for screens that sit somewhere between
86     * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi).
87     * This is not a density that applications should target, instead relying
88     * on the system to scale their {@link #DENSITY_XXHIGH} assets for them.
89     */
90    public static final int DENSITY_400 = 400;
91
92    /**
93     * Intermediate density for screens that sit somewhere between
94     * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi).
95     * This is not a density that applications should target, instead relying
96     * on the system to scale their {@link #DENSITY_XXHIGH} assets for them.
97     */
98    public static final int DENSITY_420 = 420;
99
100    /**
101     * Standard quantized DPI for extra-extra-high-density screens.
102     */
103    public static final int DENSITY_XXHIGH = 480;
104
105    /**
106     * Intermediate density for screens that sit somewhere between
107     * {@link #DENSITY_XXHIGH} (480 dpi) and {@link #DENSITY_XXXHIGH} (640 dpi).
108     * This is not a density that applications should target, instead relying
109     * on the system to scale their {@link #DENSITY_XXXHIGH} assets for them.
110     */
111    public static final int DENSITY_560 = 560;
112
113    /**
114     * Standard quantized DPI for extra-extra-extra-high-density screens.  Applications
115     * should not generally worry about this density; relying on XHIGH graphics
116     * being scaled up to it should be sufficient for almost all cases.  A typical
117     * use of this density would be 4K television screens -- 3840x2160, which
118     * is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH.
119     */
120    public static final int DENSITY_XXXHIGH = 640;
121
122    /**
123     * The reference density used throughout the system.
124     */
125    public static final int DENSITY_DEFAULT = DENSITY_MEDIUM;
126
127    /**
128     * Scaling factor to convert a density in DPI units to the density scale.
129     * @hide
130     */
131    public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT;
132
133    /**
134     * The device's current density.
135     * <p>
136     * This value reflects any changes made to the device density. To obtain
137     * the device's stable density, use {@link #DENSITY_DEVICE_STABLE}.
138     *
139     * @hide This value should not be used.
140     * @deprecated Use {@link #DENSITY_DEVICE_STABLE} to obtain the stable
141     *             device density or {@link #densityDpi} to obtain the current
142     *             density for a specific display.
143     */
144    @Deprecated
145    public static int DENSITY_DEVICE = getDeviceDensity();
146
147    /**
148     * The device's stable density.
149     * <p>
150     * This value is constant at run time and may not reflect the current
151     * display density. To obtain the current density for a specific display,
152     * use {@link #densityDpi}.
153     */
154    public static final int DENSITY_DEVICE_STABLE = getDeviceDensity();
155
156    /**
157     * The absolute width of the available display size in pixels.
158     */
159    public int widthPixels;
160    /**
161     * The absolute height of the available display size in pixels.
162     */
163    public int heightPixels;
164    /**
165     * The logical density of the display.  This is a scaling factor for the
166     * Density Independent Pixel unit, where one DIP is one pixel on an
167     * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen),
168     * providing the baseline of the system's display. Thus on a 160dpi screen
169     * this density value will be 1; on a 120 dpi screen it would be .75; etc.
170     *
171     * <p>This value does not exactly follow the real screen size (as given by
172     * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of
173     * the overall UI in steps based on gross changes in the display dpi.  For
174     * example, a 240x320 screen will have a density of 1 even if its width is
175     * 1.8", 1.3", etc. However, if the screen resolution is increased to
176     * 320x480 but the screen size remained 1.5"x2" then the density would be
177     * increased (probably to 1.5).
178     *
179     * @see #DENSITY_DEFAULT
180     */
181    public float density;
182    /**
183     * The screen density expressed as dots-per-inch.  May be either
184     * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}.
185     */
186    public int densityDpi;
187    /**
188     * A scaling factor for fonts displayed on the display.  This is the same
189     * as {@link #density}, except that it may be adjusted in smaller
190     * increments at runtime based on a user preference for the font size.
191     */
192    public float scaledDensity;
193    /**
194     * The exact physical pixels per inch of the screen in the X dimension.
195     */
196    public float xdpi;
197    /**
198     * The exact physical pixels per inch of the screen in the Y dimension.
199     */
200    public float ydpi;
201
202    /**
203     * The reported display width prior to any compatibility mode scaling
204     * being applied.
205     * @hide
206     */
207    public int noncompatWidthPixels;
208    /**
209     * The reported display height prior to any compatibility mode scaling
210     * being applied.
211     * @hide
212     */
213    public int noncompatHeightPixels;
214    /**
215     * The reported display density prior to any compatibility mode scaling
216     * being applied.
217     * @hide
218     */
219    public float noncompatDensity;
220    /**
221     * The reported display density prior to any compatibility mode scaling
222     * being applied.
223     * @hide
224     */
225    public int noncompatDensityDpi;
226    /**
227     * The reported scaled density prior to any compatibility mode scaling
228     * being applied.
229     * @hide
230     */
231    public float noncompatScaledDensity;
232    /**
233     * The reported display xdpi prior to any compatibility mode scaling
234     * being applied.
235     * @hide
236     */
237    public float noncompatXdpi;
238    /**
239     * The reported display ydpi prior to any compatibility mode scaling
240     * being applied.
241     * @hide
242     */
243    public float noncompatYdpi;
244
245    public DisplayMetrics() {
246    }
247
248    public void setTo(DisplayMetrics o) {
249        widthPixels = o.widthPixels;
250        heightPixels = o.heightPixels;
251        density = o.density;
252        densityDpi = o.densityDpi;
253        scaledDensity = o.scaledDensity;
254        xdpi = o.xdpi;
255        ydpi = o.ydpi;
256        noncompatWidthPixels = o.noncompatWidthPixels;
257        noncompatHeightPixels = o.noncompatHeightPixels;
258        noncompatDensity = o.noncompatDensity;
259        noncompatDensityDpi = o.noncompatDensityDpi;
260        noncompatScaledDensity = o.noncompatScaledDensity;
261        noncompatXdpi = o.noncompatXdpi;
262        noncompatYdpi = o.noncompatYdpi;
263    }
264
265    public void setToDefaults() {
266        widthPixels = 0;
267        heightPixels = 0;
268        density =  DENSITY_DEVICE / (float) DENSITY_DEFAULT;
269        densityDpi =  DENSITY_DEVICE;
270        scaledDensity = density;
271        xdpi = DENSITY_DEVICE;
272        ydpi = DENSITY_DEVICE;
273        noncompatWidthPixels = widthPixels;
274        noncompatHeightPixels = heightPixels;
275        noncompatDensity = density;
276        noncompatDensityDpi = densityDpi;
277        noncompatScaledDensity = scaledDensity;
278        noncompatXdpi = xdpi;
279        noncompatYdpi = ydpi;
280    }
281
282    @Override
283    public boolean equals(Object o) {
284        return o instanceof DisplayMetrics && equals((DisplayMetrics)o);
285    }
286
287    /**
288     * Returns true if these display metrics equal the other display metrics.
289     *
290     * @param other The display metrics with which to compare.
291     * @return True if the display metrics are equal.
292     */
293    public boolean equals(DisplayMetrics other) {
294        return equalsPhysical(other)
295                && scaledDensity == other.scaledDensity
296                && noncompatScaledDensity == other.noncompatScaledDensity;
297    }
298
299    /**
300     * Returns true if the physical aspects of the two display metrics
301     * are equal.  This ignores the scaled density, which is a logical
302     * attribute based on the current desired font size.
303     *
304     * @param other The display metrics with which to compare.
305     * @return True if the display metrics are equal.
306     * @hide
307     */
308    public boolean equalsPhysical(DisplayMetrics other) {
309        return other != null
310                && widthPixels == other.widthPixels
311                && heightPixels == other.heightPixels
312                && density == other.density
313                && densityDpi == other.densityDpi
314                && xdpi == other.xdpi
315                && ydpi == other.ydpi
316                && noncompatWidthPixels == other.noncompatWidthPixels
317                && noncompatHeightPixels == other.noncompatHeightPixels
318                && noncompatDensity == other.noncompatDensity
319                && noncompatDensityDpi == other.noncompatDensityDpi
320                && noncompatXdpi == other.noncompatXdpi
321                && noncompatYdpi == other.noncompatYdpi;
322    }
323
324    @Override
325    public int hashCode() {
326        return widthPixels * heightPixels * densityDpi;
327    }
328
329    @Override
330    public String toString() {
331        return "DisplayMetrics{density=" + density + ", width=" + widthPixels +
332            ", height=" + heightPixels + ", scaledDensity=" + scaledDensity +
333            ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}";
334    }
335
336    private static int getDeviceDensity() {
337        // qemu.sf.lcd_density can be used to override ro.sf.lcd_density
338        // when running in the emulator, allowing for dynamic configurations.
339        // The reason for this is that ro.sf.lcd_density is write-once and is
340        // set by the init process when it parses build.prop before anything else.
341        return SystemProperties.getInt("qemu.sf.lcd_density",
342                SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT));
343    }
344}
345