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_400 = 400;
83
84    /**
85     * Standard quantized DPI for extra-extra-high-density screens.
86     */
87    public static final int DENSITY_XXHIGH = 480;
88
89    /**
90     * Intermediate density for screens that sit somewhere between
91     * {@link #DENSITY_XXHIGH} (480 dpi) and {@link #DENSITY_XXXHIGH} (640 dpi).
92     * This is not a density that applications should target, instead relying
93     * on the system to scale their {@link #DENSITY_XXXHIGH} assets for them.
94     */
95    public static final int DENSITY_560 = 560;
96
97    /**
98     * Standard quantized DPI for extra-extra-extra-high-density screens.  Applications
99     * should not generally worry about this density; relying on XHIGH graphics
100     * being scaled up to it should be sufficient for almost all cases.  A typical
101     * use of this density would be 4K television screens -- 3840x2160, which
102     * is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH.
103     */
104    public static final int DENSITY_XXXHIGH = 640;
105
106    /**
107     * The reference density used throughout the system.
108     */
109    public static final int DENSITY_DEFAULT = DENSITY_MEDIUM;
110
111    /**
112     * Scaling factor to convert a density in DPI units to the density scale.
113     * @hide
114     */
115    public static final float DENSITY_DEFAULT_SCALE = 1.0f / DENSITY_DEFAULT;
116
117    /**
118     * The device's density.
119     * @hide because eventually this should be able to change while
120     * running, so shouldn't be a constant.
121     * @deprecated There is no longer a static density; you can find the
122     * density for a display in {@link #densityDpi}.
123     */
124    @Deprecated
125    public static int DENSITY_DEVICE = getDeviceDensity();
126
127    /**
128     * The absolute width of the display in pixels.
129     */
130    public int widthPixels;
131    /**
132     * The absolute height of the display in pixels.
133     */
134    public int heightPixels;
135    /**
136     * The logical density of the display.  This is a scaling factor for the
137     * Density Independent Pixel unit, where one DIP is one pixel on an
138     * approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen),
139     * providing the baseline of the system's display. Thus on a 160dpi screen
140     * this density value will be 1; on a 120 dpi screen it would be .75; etc.
141     *
142     * <p>This value does not exactly follow the real screen size (as given by
143     * {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of
144     * the overall UI in steps based on gross changes in the display dpi.  For
145     * example, a 240x320 screen will have a density of 1 even if its width is
146     * 1.8", 1.3", etc. However, if the screen resolution is increased to
147     * 320x480 but the screen size remained 1.5"x2" then the density would be
148     * increased (probably to 1.5).
149     *
150     * @see #DENSITY_DEFAULT
151     */
152    public float density;
153    /**
154     * The screen density expressed as dots-per-inch.  May be either
155     * {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}.
156     */
157    public int densityDpi;
158    /**
159     * A scaling factor for fonts displayed on the display.  This is the same
160     * as {@link #density}, except that it may be adjusted in smaller
161     * increments at runtime based on a user preference for the font size.
162     */
163    public float scaledDensity;
164    /**
165     * The exact physical pixels per inch of the screen in the X dimension.
166     */
167    public float xdpi;
168    /**
169     * The exact physical pixels per inch of the screen in the Y dimension.
170     */
171    public float ydpi;
172
173    /**
174     * The reported display width prior to any compatibility mode scaling
175     * being applied.
176     * @hide
177     */
178    public int noncompatWidthPixels;
179    /**
180     * The reported display height prior to any compatibility mode scaling
181     * being applied.
182     * @hide
183     */
184    public int noncompatHeightPixels;
185    /**
186     * The reported display density prior to any compatibility mode scaling
187     * being applied.
188     * @hide
189     */
190    public float noncompatDensity;
191    /**
192     * The reported display density prior to any compatibility mode scaling
193     * being applied.
194     * @hide
195     */
196    public int noncompatDensityDpi;
197    /**
198     * The reported scaled density prior to any compatibility mode scaling
199     * being applied.
200     * @hide
201     */
202    public float noncompatScaledDensity;
203    /**
204     * The reported display xdpi prior to any compatibility mode scaling
205     * being applied.
206     * @hide
207     */
208    public float noncompatXdpi;
209    /**
210     * The reported display ydpi prior to any compatibility mode scaling
211     * being applied.
212     * @hide
213     */
214    public float noncompatYdpi;
215
216    public DisplayMetrics() {
217    }
218
219    public void setTo(DisplayMetrics o) {
220        widthPixels = o.widthPixels;
221        heightPixels = o.heightPixels;
222        density = o.density;
223        densityDpi = o.densityDpi;
224        scaledDensity = o.scaledDensity;
225        xdpi = o.xdpi;
226        ydpi = o.ydpi;
227        noncompatWidthPixels = o.noncompatWidthPixels;
228        noncompatHeightPixels = o.noncompatHeightPixels;
229        noncompatDensity = o.noncompatDensity;
230        noncompatDensityDpi = o.noncompatDensityDpi;
231        noncompatScaledDensity = o.noncompatScaledDensity;
232        noncompatXdpi = o.noncompatXdpi;
233        noncompatYdpi = o.noncompatYdpi;
234    }
235
236    public void setToDefaults() {
237        widthPixels = 0;
238        heightPixels = 0;
239        density =  DENSITY_DEVICE / (float) DENSITY_DEFAULT;
240        densityDpi =  DENSITY_DEVICE;
241        scaledDensity = density;
242        xdpi = DENSITY_DEVICE;
243        ydpi = DENSITY_DEVICE;
244        noncompatWidthPixels = widthPixels;
245        noncompatHeightPixels = heightPixels;
246        noncompatDensity = density;
247        noncompatDensityDpi = densityDpi;
248        noncompatScaledDensity = scaledDensity;
249        noncompatXdpi = xdpi;
250        noncompatYdpi = ydpi;
251    }
252
253    @Override
254    public boolean equals(Object o) {
255        return o instanceof DisplayMetrics && equals((DisplayMetrics)o);
256    }
257
258    /**
259     * Returns true if these display metrics equal the other display metrics.
260     *
261     * @param other The display metrics with which to compare.
262     * @return True if the display metrics are equal.
263     */
264    public boolean equals(DisplayMetrics other) {
265        return equalsPhysical(other)
266                && scaledDensity == other.scaledDensity
267                && noncompatScaledDensity == other.noncompatScaledDensity;
268    }
269
270    /**
271     * Returns true if the physical aspects of the two display metrics
272     * are equal.  This ignores the scaled density, which is a logical
273     * attribute based on the current desired font size.
274     *
275     * @param other The display metrics with which to compare.
276     * @return True if the display metrics are equal.
277     * @hide
278     */
279    public boolean equalsPhysical(DisplayMetrics other) {
280        return other != null
281                && widthPixels == other.widthPixels
282                && heightPixels == other.heightPixels
283                && density == other.density
284                && densityDpi == other.densityDpi
285                && xdpi == other.xdpi
286                && ydpi == other.ydpi
287                && noncompatWidthPixels == other.noncompatWidthPixels
288                && noncompatHeightPixels == other.noncompatHeightPixels
289                && noncompatDensity == other.noncompatDensity
290                && noncompatDensityDpi == other.noncompatDensityDpi
291                && noncompatXdpi == other.noncompatXdpi
292                && noncompatYdpi == other.noncompatYdpi;
293    }
294
295    @Override
296    public int hashCode() {
297        return widthPixels * heightPixels * densityDpi;
298    }
299
300    @Override
301    public String toString() {
302        return "DisplayMetrics{density=" + density + ", width=" + widthPixels +
303            ", height=" + heightPixels + ", scaledDensity=" + scaledDensity +
304            ", xdpi=" + xdpi + ", ydpi=" + ydpi + "}";
305    }
306
307    private static int getDeviceDensity() {
308        // qemu.sf.lcd_density can be used to override ro.sf.lcd_density
309        // when running in the emulator, allowing for dynamic configurations.
310        // The reason for this is that ro.sf.lcd_density is write-once and is
311        // set by the init process when it parses build.prop before anything else.
312        return SystemProperties.getInt("qemu.sf.lcd_density",
313                SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT));
314    }
315}
316