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      1 /*
      2  * Copyright (C) 2011 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.camera.ui;
     18 
     19 import com.android.camera.R;
     20 
     21 import android.content.Context;
     22 import android.os.Handler;
     23 import android.util.AttributeSet;
     24 import android.view.View;
     25 import android.widget.ImageView;
     26 import android.widget.RelativeLayout;
     27 
     28 /**
     29  * A view that contains camera zoom control which could adjust the zoom in/out
     30  * if the camera supports zooming.
     31  */
     32 public abstract class ZoomControl extends RelativeLayout implements Rotatable {
     33     // The states of zoom button.
     34     public static final int ZOOM_IN = 0;
     35     public static final int ZOOM_OUT = 1;
     36     public static final int ZOOM_STOP = 2;
     37 
     38     private static final String TAG = "ZoomControl";
     39     private static final int ZOOMING_INTERVAL = 1000; // milliseconds
     40 
     41     protected ImageView mZoomIn;
     42     protected ImageView mZoomOut;
     43     protected ImageView mZoomSlider;
     44     protected int mOrientation;
     45     private Handler mHandler;
     46 
     47     public interface OnZoomChangedListener {
     48         void onZoomValueChanged(int index);  // only for immediate zoom
     49         void onZoomStateChanged(int state);  // only for smooth zoom
     50     }
     51 
     52     // The interface OnZoomIndexChangedListener is used to inform the
     53     // ZoomIndexBar about the zoom index change. The index position is between
     54     // 0 (the index is zero) and 1.0 (the index is mZoomMax).
     55     public interface OnZoomIndexChangedListener {
     56         void onZoomIndexChanged(double indexPosition);
     57     }
     58 
     59     protected int mZoomMax, mZoomIndex;
     60     private boolean mSmoothZoomSupported;
     61     private OnZoomChangedListener mListener;
     62     private OnZoomIndexChangedListener mIndexListener;
     63 
     64     protected OnIndicatorEventListener mOnIndicatorEventListener;
     65     private int mState;
     66     private int mStep;
     67 
     68     protected final Runnable mRunnable = new Runnable() {
     69         public void run() {
     70             performZoom(mState, false);
     71         }
     72     };
     73 
     74     public ZoomControl(Context context, AttributeSet attrs) {
     75         super(context, attrs);
     76         mZoomIn = addImageView(context, R.drawable.ic_zoom_in);
     77         mZoomSlider = addImageView(context, R.drawable.ic_zoom_slider);
     78         mZoomOut = addImageView(context, R.drawable.ic_zoom_out);
     79         mHandler = new Handler();
     80     }
     81 
     82     public void startZoomControl() {
     83         mZoomSlider.setPressed(true);
     84         setZoomIndex(mZoomIndex); // Update the zoom index bar.
     85     }
     86 
     87     protected ImageView addImageView(Context context, int iconResourceId) {
     88         ImageView image = new RotateImageView(context);
     89         image.setImageResource(iconResourceId);
     90         if (iconResourceId == R.drawable.ic_zoom_slider) {
     91             image.setContentDescription(getResources().getString(
     92                     R.string.accessibility_zoom_control));
     93         } else {
     94             image.setContentDescription(getResources().getString(
     95                     R.string.empty));
     96         }
     97         addView(image);
     98         return image;
     99     }
    100 
    101     public void closeZoomControl() {
    102         mZoomSlider.setPressed(false);
    103         stopZooming();
    104         if (!mSmoothZoomSupported) mHandler.removeCallbacks(mRunnable);
    105         if (mOnIndicatorEventListener != null) {
    106             mOnIndicatorEventListener.onIndicatorEvent(
    107                     OnIndicatorEventListener.EVENT_LEAVE_ZOOM_CONTROL);
    108         }
    109     }
    110 
    111     public void setZoomMax(int zoomMax) {
    112         mZoomMax = zoomMax;
    113 
    114         // Layout should be requested as the maximum zoom level is the key to
    115         // show the correct zoom slider position.
    116         requestLayout();
    117     }
    118 
    119     public void setOnZoomChangeListener(OnZoomChangedListener listener) {
    120         mListener = listener;
    121     }
    122 
    123     public void setOnIndicatorEventListener(OnIndicatorEventListener listener) {
    124         mOnIndicatorEventListener = listener;
    125     }
    126 
    127     public void setZoomIndex(int index) {
    128         if (index < 0 || index > mZoomMax) {
    129             throw new IllegalArgumentException("Invalid zoom value:" + index);
    130         }
    131         mZoomIndex = index;
    132         invalidate();
    133     }
    134 
    135     public void setSmoothZoomSupported(boolean smoothZoomSupported) {
    136         mSmoothZoomSupported = smoothZoomSupported;
    137     }
    138 
    139     private boolean zoomIn() {
    140         return (mZoomIndex == mZoomMax) ? false : changeZoomIndex(mZoomIndex + mStep);
    141     }
    142 
    143     private boolean zoomOut() {
    144         return (mZoomIndex == 0) ? false : changeZoomIndex(mZoomIndex - mStep);
    145     }
    146 
    147     protected void setZoomStep(int step) {
    148         mStep = step;
    149     }
    150 
    151     private void stopZooming() {
    152         if (mSmoothZoomSupported) {
    153             if (mListener != null) mListener.onZoomStateChanged(ZOOM_STOP);
    154         }
    155     }
    156 
    157     // Called from ZoomControlWheel to change the zoom level.
    158     // TODO: merge the zoom control for both platforms.
    159     protected void performZoom(int state) {
    160         performZoom(state, true);
    161     }
    162 
    163     private void performZoom(int state, boolean fromUser) {
    164         if ((mState == state) && fromUser) return;
    165         if (fromUser) mHandler.removeCallbacks(mRunnable);
    166         mState = state;
    167         switch (state) {
    168             case ZOOM_IN:
    169                 zoomIn();
    170                 break;
    171             case ZOOM_OUT:
    172                 zoomOut();
    173                 break;
    174             case ZOOM_STOP:
    175                 stopZooming();
    176                 break;
    177         }
    178         if (!mSmoothZoomSupported) {
    179             // Repeat the zoom action on tablet as the user is still holding
    180             // the zoom slider.
    181             mHandler.postDelayed(mRunnable, ZOOMING_INTERVAL / mZoomMax);
    182         }
    183     }
    184 
    185     // Called from ZoomControlBar to change the zoom level.
    186     protected void performZoom(double zoomPercentage) {
    187         int index = (int) (mZoomMax * zoomPercentage);
    188         if (mZoomIndex == index) return;
    189         changeZoomIndex(index);
    190    }
    191 
    192     private boolean changeZoomIndex(int index) {
    193         if (mListener != null) {
    194             if (mSmoothZoomSupported) {
    195                 int zoomType = (index < mZoomIndex) ? ZOOM_OUT : ZOOM_IN;
    196                 if (((zoomType == ZOOM_IN) && (mZoomIndex != mZoomMax)) ||
    197                         ((zoomType == ZOOM_OUT) && (mZoomIndex != 0))) {
    198                     mListener.onZoomStateChanged(zoomType);
    199                 }
    200             } else {
    201                 if (index > mZoomMax) index = mZoomMax;
    202                 if (index < 0) index = 0;
    203                 mListener.onZoomValueChanged(index);
    204                 mZoomIndex = index;
    205             }
    206         }
    207         return true;
    208     }
    209 
    210     public void setOrientation(int orientation) {
    211         mOrientation = orientation;
    212         int count = getChildCount();
    213         for (int i = 0 ; i < count ; ++i) {
    214             View view = getChildAt(i);
    215             if (view instanceof RotateImageView) {
    216                 ((RotateImageView) view).setOrientation(orientation);
    217             }
    218         }
    219     }
    220 
    221     @Override
    222     public void setActivated(boolean activated) {
    223         super.setActivated(activated);
    224         mZoomIn.setActivated(activated);
    225         mZoomOut.setActivated(activated);
    226     }
    227 }
    228