/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.util;
import android.content.res.CompatibilityInfo;
import android.content.res.Configuration;
import android.os.*;
/**
* A structure describing general information about a display, such as its
* size, density, and font scaling.
* <p>To access the DisplayMetrics members, initialize an object like this:</p>
* <pre> DisplayMetrics metrics = new DisplayMetrics();
* getWindowManager().getDefaultDisplay().getMetrics(metrics);</pre>
*/
public class DisplayMetrics {
/**
* Standard quantized DPI for low-density screens.
*/
public static final int DENSITY_LOW = 120;
/**
* Standard quantized DPI for medium-density screens.
*/
public static final int DENSITY_MEDIUM = 160;
/**
* Standard quantized DPI for high-density screens.
*/
public static final int DENSITY_HIGH = 240;
/**
* The reference density used throughout the system.
*/
public static final int DENSITY_DEFAULT = DENSITY_MEDIUM;
/**
* The device's density.
* @hide becase eventually this should be able to change while
* running, so shouldn't be a constant.
*/
public static final int DENSITY_DEVICE = getDeviceDensity();
/**
* The absolute width of the display in pixels.
*/
public int widthPixels;
/**
* The absolute height of the display in pixels.
*/
public int heightPixels;
/**
* The logical density of the display. This is a scaling factor for the
* Density Independent Pixel unit, where one DIP is one pixel on an
* approximately 160 dpi screen (for example a 240x320, 1.5"x2" screen),
* providing the baseline of the system's display. Thus on a 160dpi screen
* this density value will be 1; on a 120 dpi screen it would be .75; etc.
*
* <p>This value does not exactly follow the real screen size (as given by
* {@link #xdpi} and {@link #ydpi}, but rather is used to scale the size of
* the overall UI in steps based on gross changes in the display dpi. For
* example, a 240x320 screen will have a density of 1 even if its width is
* 1.8", 1.3", etc. However, if the screen resolution is increased to
* 320x480 but the screen size remained 1.5"x2" then the density would be
* increased (probably to 1.5).
*
* @see #DENSITY_DEFAULT
*/
public float density;
/**
* The screen density expressed as dots-per-inch. May be either
* {@link #DENSITY_LOW}, {@link #DENSITY_MEDIUM}, or {@link #DENSITY_HIGH}.
*/
public int densityDpi;
/**
* A scaling factor for fonts displayed on the display. This is the same
* as {@link #density}, except that it may be adjusted in smaller
* increments at runtime based on a user preference for the font size.
*/
public float scaledDensity;
/**
* The exact physical pixels per inch of the screen in the X dimension.
*/
public float xdpi;
/**
* The exact physical pixels per inch of the screen in the Y dimension.
*/
public float ydpi;
public DisplayMetrics() {
}
public void setTo(DisplayMetrics o) {
widthPixels = o.widthPixels;
heightPixels = o.heightPixels;
density = o.density;
densityDpi = o.densityDpi;
scaledDensity = o.scaledDensity;
xdpi = o.xdpi;
ydpi = o.ydpi;
}
public void setToDefaults() {
widthPixels = 0;
heightPixels = 0;
density = DENSITY_DEVICE / (float) DENSITY_DEFAULT;
densityDpi = DENSITY_DEVICE;
scaledDensity = density;
xdpi = DENSITY_DEVICE;
ydpi = DENSITY_DEVICE;
}
/**
* Update the display metrics based on the compatibility info and orientation
* NOTE: DO NOT EXPOSE THIS API! It is introducing a circular dependency
* with the higher-level android.res package.
* {@hide}
*/
public void updateMetrics(CompatibilityInfo compatibilityInfo, int orientation,
int screenLayout) {
boolean expandable = compatibilityInfo.isConfiguredExpandable();
boolean largeScreens = compatibilityInfo.isConfiguredLargeScreens();
// Note: this assume that configuration is updated before calling
// updateMetrics method.
if (!expandable) {
if ((screenLayout&Configuration.SCREENLAYOUT_COMPAT_NEEDED) == 0) {
expandable = true;
// the current screen size is compatible with non-resizing apps.
compatibilityInfo.setExpandable(true);
} else {
compatibilityInfo.setExpandable(false);
}
}
if (!largeScreens) {
if ((screenLayout&Configuration.SCREENLAYOUT_SIZE_MASK)
!= Configuration.SCREENLAYOUT_SIZE_LARGE) {
largeScreens = true;
// the current screen size is not large.
compatibilityInfo.setLargeScreens(true);
} else {
compatibilityInfo.setLargeScreens(false);
}
}
if (!expandable || !largeScreens) {
// This is a larger screen device and the app is not
// compatible with large screens, so diddle it.
// Figure out the compatibility width and height of the screen.
int defaultWidth;
int defaultHeight;
switch (orientation) {
case Configuration.ORIENTATION_LANDSCAPE: {
defaultWidth = (int)(CompatibilityInfo.DEFAULT_PORTRAIT_HEIGHT * density +
0.5f);
defaultHeight = (int)(CompatibilityInfo.DEFAULT_PORTRAIT_WIDTH * density +
0.5f);
break;
}
case Configuration.ORIENTATION_PORTRAIT:
case Configuration.ORIENTATION_SQUARE:
default: {
defaultWidth = (int)(CompatibilityInfo.DEFAULT_PORTRAIT_WIDTH * density +
0.5f);
defaultHeight = (int)(CompatibilityInfo.DEFAULT_PORTRAIT_HEIGHT * density +
0.5f);
break;
}
case Configuration.ORIENTATION_UNDEFINED: {
// don't change
return;
}
}
if (defaultWidth < widthPixels) {
// content/window's x offset in original pixels
widthPixels = defaultWidth;
}
if (defaultHeight < heightPixels) {
heightPixels = defaultHeight;
}
}
if (compatibilityInfo.isScalingRequired()) {
float invertedRatio = compatibilityInfo.applicationInvertedScale;
density *= invertedRatio;
densityDpi = (int)((density*DisplayMetrics.DENSITY_DEFAULT)+.5f);
scaledDensity *= invertedRatio;
xdpi *= invertedRatio;
ydpi *= invertedRatio;
widthPixels = (int) (widthPixels * invertedRatio + 0.5f);
heightPixels = (int) (heightPixels * invertedRatio + 0.5f);
}
}
@Override
public String toString() {
return "DisplayMetrics{density=" + density + ", width=" + widthPixels +
", height=" + heightPixels + ", scaledDensity=" + scaledDensity +
", xdpi=" + xdpi + ", ydpi=" + ydpi + "}";
}
private static int getDeviceDensity() {
// qemu.sf.lcd_density can be used to override ro.sf.lcd_density
// when running in the emulator, allowing for dynamic configurations.
// The reason for this is that ro.sf.lcd_density is write-once and is
// set by the init process when it parses build.prop before anything else.
return SystemProperties.getInt("qemu.sf.lcd_density",
SystemProperties.getInt("ro.sf.lcd_density", DENSITY_DEFAULT));
}
}