core/java/android/view/Display.java

/*
 * 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.view;

import android.content.res.CompatibilityInfo;
import android.graphics.Point;
import android.graphics.Rect;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.util.DisplayMetrics;
import android.util.Slog;

/**
 * Provides information about the display size and density.
 */
public class Display {
    static final String TAG = "Display";
    static final boolean DEBUG_DISPLAY_SIZE = false;

    /**
     * The default Display id.
     */
    public static final int DEFAULT_DISPLAY = 0;

    /**
     * Use {@link android.view.WindowManager#getDefaultDisplay()
     * WindowManager.getDefaultDisplay()} to create a Display object.
     * Display gives you access to some information about a particular display
     * connected to the device.
     */
    Display(int display, CompatibilityInfoHolder compatInfo) {
        // initalize the statics when this class is first instansiated. This is
        // done here instead of in the static block because Zygote
        synchronized (sStaticInit) {
            if (!sInitialized) {
                nativeClassInit();
                sInitialized = true;
            }
        }
        mCompatibilityInfo = compatInfo != null ? compatInfo : new CompatibilityInfoHolder();
        mDisplay = display;
        init(display);
    }

    /**
     * Returns the index of this display.  This is currently undefined; do
     * not use.
     */
    public int getDisplayId() {
        return mDisplay;
    }

    /**
     * Returns the number of displays connected to the device.  This is
     * currently undefined; do not use.
     */
    native static int getDisplayCount();
    
    /**
     * Gets the size of the display, in pixels.
     * <p>
     * Note that this value should <em>not</em> be used for computing layouts,
     * since a device will typically have screen decoration (such as a status bar)
     * along the edges of the display that reduce the amount of application
     * space available from the size returned here.  Layouts should instead use
     * the window size.
     * </p><p>
     * The size is adjusted based on the current rotation of the display.
     * </p><p>
     * The size returned by this method does not necessarily represent the
     * actual raw size (native resolution) of the display.  The returned size may
     * be adjusted to exclude certain system decor elements that are always visible.
     * It may also be scaled to provide compatibility with older applications that
     * were originally designed for smaller displays.
     * </p>
     *
     * @param outSize A {@link Point} object to receive the size information.
     */
    public void getSize(Point outSize) {
        getSizeInternal(outSize, true);
    }

    private void getSizeInternal(Point outSize, boolean doCompat) {
        try {
            IWindowManager wm = getWindowManager();
            if (wm != null) {
                wm.getDisplaySize(outSize);
                CompatibilityInfo ci;
                if (doCompat && (ci=mCompatibilityInfo.getIfNeeded()) != null) {
                    synchronized (mTmpMetrics) {
                        mTmpMetrics.noncompatWidthPixels = outSize.x;
                        mTmpMetrics.noncompatHeightPixels = outSize.y;
                        mTmpMetrics.density = mDensity;
                        ci.applyToDisplayMetrics(mTmpMetrics);
                        outSize.x = mTmpMetrics.widthPixels;
                        outSize.y = mTmpMetrics.heightPixels;
                    }
                }
            } else {
                // This is just for boot-strapping, initializing the
                // system process before the window manager is up.
                outSize.x = getRawWidth();
                outSize.y = getRawHeight();
            }
            if (false) {
                RuntimeException here = new RuntimeException("here");
                here.fillInStackTrace();
                Slog.v(TAG, "Returning display size: " + outSize, here);
            }
            if (DEBUG_DISPLAY_SIZE && doCompat) Slog.v(
                    TAG, "Returning display size: " + outSize);
        } catch (RemoteException e) {
            Slog.w("Display", "Unable to get display size", e);
        }
    }
    
    /**
     * Gets the size of the display as a rectangle, in pixels.
     *
     * @param outSize A {@link Rect} object to receive the size information.
     * @see #getSize(Point)
     */
    public void getRectSize(Rect outSize) {
        synchronized (mTmpPoint) {
            getSizeInternal(mTmpPoint, true);
            outSize.set(0, 0, mTmpPoint.x, mTmpPoint.y);
        }
    }

    /**
     * Return the maximum screen size dimension that will happen.  This is
     * mostly for wallpapers.
     * @hide
     */
    public int getMaximumSizeDimension() {
        try {
            IWindowManager wm = getWindowManager();
            return wm.getMaximumSizeDimension();
        } catch (RemoteException e) {
            Slog.w("Display", "Unable to get display maximum size dimension", e);
            return 0;
        }
    }

    /**
     * @deprecated Use {@link #getSize(Point)} instead.
     */
    @Deprecated
    public int getWidth() {
        synchronized (mTmpPoint) {
            long now = SystemClock.uptimeMillis();
            if (now > (mLastGetTime+20)) {
                getSizeInternal(mTmpPoint, true);
                mLastGetTime = now;
            }
            return mTmpPoint.x;
        }
    }

    /**
     * @deprecated Use {@link #getSize(Point)} instead.
     */
    @Deprecated
    public int getHeight() {
        synchronized (mTmpPoint) {
            long now = SystemClock.uptimeMillis();
            if (now > (mLastGetTime+20)) {
                getSizeInternal(mTmpPoint, true);
                mLastGetTime = now;
            }
            return mTmpPoint.y;
        }
    }

    /**
     * Gets the real size of the display without subtracting any window decor or
     * applying any compatibility scale factors.
     * <p>
     * The real size may be smaller than the raw size when the window manager
     * is emulating a smaller display (using adb shell am display-size).
     * </p><p>
     * The size is adjusted based on the current rotation of the display.
     * </p>
     * @hide
     */
    public void getRealSize(Point outSize) {
        try {
            IWindowManager wm = getWindowManager();
            if (wm != null) {
                wm.getRealDisplaySize(outSize);
            } else {
                // This is just for boot-strapping, initializing the
                // system process before the window manager is up.
                outSize.x = getRawWidth();
                outSize.y = getRawHeight();
            }
            if (DEBUG_DISPLAY_SIZE) Slog.v(
                    TAG, "Returning real display size: " + outSize);
        } catch (RemoteException e) {
            Slog.w("Display", "Unable to get real display size", e);
        }
    }

    /**
     * Gets the raw width of the display, in pixels.
     * <p>
     * The size is adjusted based on the current rotation of the display.
     * </p>
     * @hide
     */
    public int getRawWidth() {
        int w = getRawWidthNative();
        if (DEBUG_DISPLAY_SIZE) Slog.v(
                TAG, "Returning raw display width: " + w);
        return w;
    }
    private native int getRawWidthNative();

    /**
     * Gets the raw height of the display, in pixels.
     * <p>
     * The size is adjusted based on the current rotation of the display.
     * </p>
     * @hide
     */
    public int getRawHeight() {
        int h = getRawHeightNative();
        if (DEBUG_DISPLAY_SIZE) Slog.v(
                TAG, "Returning raw display height: " + h);
        return h;
    }
    private native int getRawHeightNative();
    
    /**
     * Returns the rotation of the screen from its "natural" orientation.
     * The returned value may be {@link Surface#ROTATION_0 Surface.ROTATION_0}
     * (no rotation), {@link Surface#ROTATION_90 Surface.ROTATION_90},
     * {@link Surface#ROTATION_180 Surface.ROTATION_180}, or
     * {@link Surface#ROTATION_270 Surface.ROTATION_270}.  For
     * example, if a device has a naturally tall screen, and the user has
     * turned it on its side to go into a landscape orientation, the value
     * returned here may be either {@link Surface#ROTATION_90 Surface.ROTATION_90}
     * or {@link Surface#ROTATION_270 Surface.ROTATION_270} depending on
     * the direction it was turned.  The angle is the rotation of the drawn
     * graphics on the screen, which is the opposite direction of the physical
     * rotation of the device.  For example, if the device is rotated 90
     * degrees counter-clockwise, to compensate rendering will be rotated by
     * 90 degrees clockwise and thus the returned value here will be
     * {@link Surface#ROTATION_90 Surface.ROTATION_90}.
     */
    public int getRotation() {
        return getOrientation();
    }
    
    /**
     * @deprecated use {@link #getRotation}
     * @return orientation of this display.
     */
    @Deprecated native public int getOrientation();

    /**
     * Return the native pixel format of the display.  The returned value
     * may be one of the constants int {@link android.graphics.PixelFormat}.
     */
    public int getPixelFormat() {
        return mPixelFormat;
    }
    
    /**
     * Return the refresh rate of this display in frames per second.
     */
    public float getRefreshRate() {
        return mRefreshRate;
    }
    
    /**
     * Gets display metrics that describe the size and density of this display.
     * <p>
     * The size is adjusted based on the current rotation of the display.
     * </p><p>
     * The size returned by this method does not necessarily represent the
     * actual raw size (native resolution) of the display.  The returned size may
     * be adjusted to exclude certain system decor elements that are always visible.
     * It may also be scaled to provide compatibility with older applications that
     * were originally designed for smaller displays.
     * </p>
     *
     * @param outMetrics A {@link DisplayMetrics} object to receive the metrics.
     */
    public void getMetrics(DisplayMetrics outMetrics) {
        synchronized (mTmpPoint) {
            getSizeInternal(mTmpPoint, false);
            getMetricsWithSize(outMetrics, mTmpPoint.x, mTmpPoint.y);
        }

        CompatibilityInfo ci = mCompatibilityInfo.getIfNeeded();
        if (ci != null) {
            ci.applyToDisplayMetrics(outMetrics);
        }

        if (DEBUG_DISPLAY_SIZE) Slog.v(TAG, "Returning DisplayMetrics: "
                + outMetrics.widthPixels + "x" + outMetrics.heightPixels
                + " " + outMetrics.density);
    }

    /**
     * Gets display metrics based on the real size of this display.
     * @hide
     */
    public void getRealMetrics(DisplayMetrics outMetrics) {
        synchronized (mTmpPoint) {
            getRealSize(mTmpPoint);
            getMetricsWithSize(outMetrics, mTmpPoint.x, mTmpPoint.y);
        }
    }

    /**
     * If the display is mirrored to an external HDMI display, returns the
     * width of that display.
     * @hide
     */
    public int getRawExternalWidth() {
        return 1280;
    }

    /**
     * If the display is mirrored to an external HDMI display, returns the
     * height of that display.
     * @hide
     */
    public int getRawExternalHeight() {
        return 720;
    }

    /**
     * Gets display metrics based on an explicit assumed display size.
     * @hide
     */
    public void getMetricsWithSize(DisplayMetrics outMetrics,
            int width, int height) {
        outMetrics.densityDpi   = (int)((mDensity*DisplayMetrics.DENSITY_DEFAULT)+.5f);

        outMetrics.noncompatWidthPixels  = outMetrics.widthPixels = width;
        outMetrics.noncompatHeightPixels = outMetrics.heightPixels = height;

        outMetrics.density = outMetrics.noncompatDensity = mDensity;
        outMetrics.scaledDensity = outMetrics.noncompatScaledDensity = outMetrics.density;
        outMetrics.xdpi = outMetrics.noncompatXdpi = mDpiX;
        outMetrics.ydpi = outMetrics.noncompatYdpi = mDpiY;
    }

    static IWindowManager getWindowManager() {
        synchronized (sStaticInit) {
            if (sWindowManager == null) {
                sWindowManager = IWindowManager.Stub.asInterface(
                        ServiceManager.getService("window"));
            }
            return sWindowManager;
        }
    }

    /*
     * We use a class initializer to allow the native code to cache some
     * field offsets.
     */
    native private static void nativeClassInit();
    
    private native void init(int display);

    private final CompatibilityInfoHolder mCompatibilityInfo;
    private final int   mDisplay;
    // Following fields are initialized from native code
    private int         mPixelFormat;
    private float       mRefreshRate;
    /*package*/ float   mDensity;
    /*package*/ float   mDpiX;
    /*package*/ float   mDpiY;
    
    private final Point mTmpPoint = new Point();
    private final DisplayMetrics mTmpMetrics = new DisplayMetrics();
    private float mLastGetTime;

    private static final Object sStaticInit = new Object();
    private static boolean sInitialized = false;
    private static IWindowManager sWindowManager;

    /**
     * Returns a display object which uses the metric's width/height instead.
     * @hide
     */
    public static Display createCompatibleDisplay(int displayId, CompatibilityInfoHolder compat) {
        return new Display(displayId, compat);
    }
}