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      1 /*
      2  * Copyright (C) 2015 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 
     17 package com.android.settingslib.display;
     18 
     19 import com.android.settingslib.R;
     20 
     21 import android.content.Context;
     22 import android.content.res.Resources;
     23 import android.hardware.display.DisplayManager;
     24 import android.os.AsyncTask;
     25 import android.os.RemoteException;
     26 import android.os.UserHandle;
     27 import android.util.DisplayMetrics;
     28 import android.util.Log;
     29 import android.util.MathUtils;
     30 import android.view.Display;
     31 import android.view.IWindowManager;
     32 import android.view.WindowManagerGlobal;
     33 
     34 import java.util.Arrays;
     35 
     36 /**
     37  * Utility methods for working with display density.
     38  */
     39 public class DisplayDensityUtils {
     40     private static final String LOG_TAG = "DisplayDensityUtils";
     41 
     42     /** Minimum increment between density scales. */
     43     private static final float MIN_SCALE_INTERVAL = 0.09f;
     44 
     45     /** Minimum density scale. This is available on all devices. */
     46     private static final float MIN_SCALE = 0.85f;
     47 
     48     /** Maximum density scale. The actual scale used depends on the device. */
     49     private static final float MAX_SCALE = 1.50f;
     50 
     51     /** Summary used for "default" scale. */
     52     public static final int SUMMARY_DEFAULT = R.string.screen_zoom_summary_default;
     53 
     54     /** Summary used for "custom" scale. */
     55     private static final int SUMMARY_CUSTOM = R.string.screen_zoom_summary_custom;
     56 
     57     /**
     58      * Summaries for scales smaller than "default" in order of smallest to
     59      * largest.
     60      */
     61     private static final int[] SUMMARIES_SMALLER = new int[] {
     62             R.string.screen_zoom_summary_small
     63     };
     64 
     65     /**
     66      * Summaries for scales larger than "default" in order of smallest to
     67      * largest.
     68      */
     69     private static final int[] SUMMARIES_LARGER = new int[] {
     70             R.string.screen_zoom_summary_large,
     71             R.string.screen_zoom_summary_very_large,
     72             R.string.screen_zoom_summary_extremely_large,
     73     };
     74 
     75     /**
     76      * Minimum allowed screen dimension, corresponds to resource qualifiers
     77      * "small" or "sw320dp". This value must be at least the minimum screen
     78      * size required by the CDD so that we meet developer expectations.
     79      */
     80     private static final int MIN_DIMENSION_DP = 320;
     81 
     82     private final String[] mEntries;
     83     private final int[] mValues;
     84 
     85     private final int mDefaultDensity;
     86     private final int mCurrentIndex;
     87 
     88     public DisplayDensityUtils(Context context) {
     89         final int defaultDensity = DisplayDensityUtils.getDefaultDisplayDensity(
     90                 Display.DEFAULT_DISPLAY);
     91         if (defaultDensity <= 0) {
     92             mEntries = null;
     93             mValues = null;
     94             mDefaultDensity = 0;
     95             mCurrentIndex = -1;
     96             return;
     97         }
     98 
     99         final Resources res = context.getResources();
    100         final DisplayMetrics metrics = new DisplayMetrics();
    101         context.getDisplay().getRealMetrics(metrics);
    102 
    103         final int currentDensity = metrics.densityDpi;
    104         int currentDensityIndex = -1;
    105 
    106         // Compute number of "larger" and "smaller" scales for this display.
    107         final int minDimensionPx = Math.min(metrics.widthPixels, metrics.heightPixels);
    108         final int maxDensity = DisplayMetrics.DENSITY_MEDIUM * minDimensionPx / MIN_DIMENSION_DP;
    109         final float maxScale = Math.min(MAX_SCALE, maxDensity / (float) defaultDensity);
    110         final float minScale = MIN_SCALE;
    111         final int numLarger = (int) MathUtils.constrain((maxScale - 1) / MIN_SCALE_INTERVAL,
    112                 0, SUMMARIES_LARGER.length);
    113         final int numSmaller = (int) MathUtils.constrain((1 - minScale) / MIN_SCALE_INTERVAL,
    114                 0, SUMMARIES_SMALLER.length);
    115 
    116         String[] entries = new String[1 + numSmaller + numLarger];
    117         int[] values = new int[entries.length];
    118         int curIndex = 0;
    119 
    120         if (numSmaller > 0) {
    121             final float interval = (1 - minScale) / numSmaller;
    122             for (int i = numSmaller - 1; i >= 0; i--) {
    123                 // Round down to a multiple of 2 by truncating the low bit.
    124                 final int density = ((int) (defaultDensity * (1 - (i + 1) * interval))) & ~1;
    125                 if (currentDensity == density) {
    126                     currentDensityIndex = curIndex;
    127                 }
    128                 entries[curIndex] = res.getString(SUMMARIES_SMALLER[i]);
    129                 values[curIndex] = density;
    130                 curIndex++;
    131             }
    132         }
    133 
    134         if (currentDensity == defaultDensity) {
    135             currentDensityIndex = curIndex;
    136         }
    137         values[curIndex] = defaultDensity;
    138         entries[curIndex] = res.getString(SUMMARY_DEFAULT);
    139         curIndex++;
    140 
    141         if (numLarger > 0) {
    142             final float interval = (maxScale - 1) / numLarger;
    143             for (int i = 0; i < numLarger; i++) {
    144                 // Round down to a multiple of 2 by truncating the low bit.
    145                 final int density = ((int) (defaultDensity * (1 + (i + 1) * interval))) & ~1;
    146                 if (currentDensity == density) {
    147                     currentDensityIndex = curIndex;
    148                 }
    149                 values[curIndex] = density;
    150                 entries[curIndex] = res.getString(SUMMARIES_LARGER[i]);
    151                 curIndex++;
    152             }
    153         }
    154 
    155         final int displayIndex;
    156         if (currentDensityIndex >= 0) {
    157             displayIndex = currentDensityIndex;
    158         } else {
    159             // We don't understand the current density. Must have been set by
    160             // someone else. Make room for another entry...
    161             int newLength = values.length + 1;
    162             values = Arrays.copyOf(values, newLength);
    163             values[curIndex] = currentDensity;
    164 
    165             entries = Arrays.copyOf(entries, newLength);
    166             entries[curIndex] = res.getString(SUMMARY_CUSTOM, currentDensity);
    167 
    168             displayIndex = curIndex;
    169         }
    170 
    171         mDefaultDensity = defaultDensity;
    172         mCurrentIndex = displayIndex;
    173         mEntries = entries;
    174         mValues = values;
    175     }
    176 
    177     public String[] getEntries() {
    178         return mEntries;
    179     }
    180 
    181     public int[] getValues() {
    182         return mValues;
    183     }
    184 
    185     public int getCurrentIndex() {
    186         return mCurrentIndex;
    187     }
    188 
    189     public int getDefaultDensity() {
    190         return mDefaultDensity;
    191     }
    192 
    193     /**
    194      * Returns the default density for the specified display.
    195      *
    196      * @param displayId the identifier of the display
    197      * @return the default density of the specified display, or {@code -1} if
    198      *         the display does not exist or the density could not be obtained
    199      */
    200     private static int getDefaultDisplayDensity(int displayId) {
    201        try {
    202            final IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
    203            return wm.getInitialDisplayDensity(displayId);
    204        } catch (RemoteException exc) {
    205            return -1;
    206        }
    207     }
    208 
    209     /**
    210      * Asynchronously applies display density changes to the specified display.
    211      * <p>
    212      * The change will be applied to the user specified by the value of
    213      * {@link UserHandle#myUserId()} at the time the method is called.
    214      *
    215      * @param displayId the identifier of the display to modify
    216      */
    217     public static void clearForcedDisplayDensity(final int displayId) {
    218         final int userId = UserHandle.myUserId();
    219         AsyncTask.execute(() -> {
    220             try {
    221                 final IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
    222                 wm.clearForcedDisplayDensityForUser(displayId, userId);
    223             } catch (RemoteException exc) {
    224                 Log.w(LOG_TAG, "Unable to clear forced display density setting");
    225             }
    226         });
    227     }
    228 
    229     /**
    230      * Asynchronously applies display density changes to the specified display.
    231      * <p>
    232      * The change will be applied to the user specified by the value of
    233      * {@link UserHandle#myUserId()} at the time the method is called.
    234      *
    235      * @param displayId the identifier of the display to modify
    236      * @param density the density to force for the specified display
    237      */
    238     public static void setForcedDisplayDensity(final int displayId, final int density) {
    239         final int userId = UserHandle.myUserId();
    240         AsyncTask.execute(() -> {
    241             try {
    242                 final IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
    243                 wm.setForcedDisplayDensityForUser(displayId, density, userId);
    244             } catch (RemoteException exc) {
    245                 Log.w(LOG_TAG, "Unable to save forced display density setting");
    246             }
    247         });
    248     }
    249 }
    250