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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 {
     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 mSliderPosition = 0;
     45     protected int mDegree;
     46     private Handler mHandler;
     47 
     48     public interface OnZoomChangedListener {
     49         void onZoomValueChanged(int index);  // only for immediate zoom
     50         void onZoomStateChanged(int state);  // only for smooth zoom
     51     }
     52 
     53     // The interface OnZoomIndexChangedListener is used to inform the
     54     // ZoomIndexBar about the zoom index change. The index position is between
     55     // 0 (the index is zero) and 1.0 (the index is mZoomMax).
     56     public interface OnZoomIndexChangedListener {
     57         void onZoomIndexChanged(double indexPosition);
     58     }
     59 
     60     protected int mZoomMax, mZoomIndex;
     61     private boolean mSmoothZoomSupported;
     62     private OnZoomChangedListener mListener;
     63     private OnZoomIndexChangedListener mIndexListener;
     64 
     65     protected OnIndicatorEventListener mOnIndicatorEventListener;
     66     private int mState;
     67     private int mStep;
     68 
     69     protected final Runnable mRunnable = new Runnable() {
     70         public void run() {
     71             performZoom(mState, false);
     72         }
     73     };
     74 
     75     public ZoomControl(Context context, AttributeSet attrs) {
     76         super(context, attrs);
     77         mZoomIn = addImageView(context, R.drawable.ic_zoom_in);
     78         mZoomSlider = addImageView(context, R.drawable.ic_zoom_slider);
     79         mZoomOut = addImageView(context, R.drawable.ic_zoom_out);
     80         mHandler = new Handler();
     81     }
     82 
     83     public void startZoomControl() {
     84         mZoomSlider.setPressed(true);
     85         setZoomIndex(mZoomIndex); // Update the zoom index bar.
     86     }
     87 
     88     protected ImageView addImageView(Context context, int iconResourceId) {
     89         ImageView image = new RotateImageView(context);
     90         image.setImageResource(iconResourceId);
     91         if (iconResourceId == R.drawable.ic_zoom_slider) {
     92             image.setContentDescription(getResources().getString(
     93                     R.string.accessibility_zoom_control));
     94         } else {
     95             image.setContentDescription(getResources().getString(
     96                     R.string.empty));
     97         }
     98         addView(image);
     99         return image;
    100     }
    101 
    102     public void closeZoomControl() {
    103         mZoomSlider.setPressed(false);
    104         stopZooming();
    105         if (!mSmoothZoomSupported) mHandler.removeCallbacks(mRunnable);
    106         if (mOnIndicatorEventListener != null) {
    107             mOnIndicatorEventListener.onIndicatorEvent(
    108                     OnIndicatorEventListener.EVENT_LEAVE_ZOOM_CONTROL);
    109         }
    110     }
    111 
    112     public void setZoomMax(int zoomMax) {
    113         mZoomMax = zoomMax;
    114 
    115         // Layout should be requested as the maximum zoom level is the key to
    116         // show the correct zoom slider position.
    117         requestLayout();
    118     }
    119 
    120     public void setOnZoomChangeListener(OnZoomChangedListener listener) {
    121         mListener = listener;
    122     }
    123 
    124     public void setOnIndicatorEventListener(OnIndicatorEventListener listener) {
    125         mOnIndicatorEventListener = listener;
    126     }
    127 
    128     public void setZoomIndex(int index) {
    129         if (index < 0 || index > mZoomMax) {
    130             throw new IllegalArgumentException("Invalid zoom value:" + index);
    131         }
    132         mZoomIndex = index;
    133         invalidate();
    134     }
    135 
    136     public void setSmoothZoomSupported(boolean smoothZoomSupported) {
    137         mSmoothZoomSupported = smoothZoomSupported;
    138     }
    139 
    140     private boolean zoomIn() {
    141         return (mZoomIndex == mZoomMax) ? false : changeZoomIndex(mZoomIndex + mStep);
    142     }
    143 
    144     private boolean zoomOut() {
    145         return (mZoomIndex == 0) ? false : changeZoomIndex(mZoomIndex - mStep);
    146     }
    147 
    148     protected void setZoomStep(int step) {
    149         mStep = step;
    150     }
    151 
    152     private void stopZooming() {
    153         if (mSmoothZoomSupported) {
    154             if (mListener != null) mListener.onZoomStateChanged(ZOOM_STOP);
    155         }
    156     }
    157 
    158     // Called from ZoomControlWheel to change the zoom level.
    159     // TODO: merge the zoom control for both platforms.
    160     protected void performZoom(int state) {
    161         performZoom(state, true);
    162     }
    163 
    164     private void performZoom(int state, boolean fromUser) {
    165         if ((mState == state) && fromUser) return;
    166         if (fromUser) mHandler.removeCallbacks(mRunnable);
    167         mState = state;
    168         switch (state) {
    169             case ZOOM_IN:
    170                 zoomIn();
    171                 break;
    172             case ZOOM_OUT:
    173                 zoomOut();
    174                 break;
    175             case ZOOM_STOP:
    176                 stopZooming();
    177                 break;
    178         }
    179         if (!mSmoothZoomSupported) {
    180             // Repeat the zoom action on tablet as the user is still holding
    181             // the zoom slider.
    182             mHandler.postDelayed(mRunnable, ZOOMING_INTERVAL / mZoomMax);
    183         }
    184     }
    185 
    186     // Called from ZoomControlBar to change the zoom level.
    187     protected void performZoom(double zoomPercentage) {
    188         int index = (int) (mZoomMax * zoomPercentage);
    189         if (mZoomIndex == index) return;
    190         changeZoomIndex(index);
    191    }
    192 
    193     private boolean changeZoomIndex(int index) {
    194         if (mListener != null) {
    195             if (mSmoothZoomSupported) {
    196                 int zoomType = (index < mZoomIndex) ? ZOOM_OUT : ZOOM_IN;
    197                 if (((zoomType == ZOOM_IN) && (mZoomIndex != mZoomMax)) ||
    198                         ((zoomType == ZOOM_OUT) && (mZoomIndex != 0))) {
    199                     mListener.onZoomStateChanged(zoomType);
    200                 }
    201             } else {
    202                 if (index > mZoomMax) index = mZoomMax;
    203                 if (index < 0) index = 0;
    204                 mListener.onZoomValueChanged(index);
    205                 mZoomIndex = index;
    206             }
    207         }
    208         return true;
    209     }
    210 
    211     public void setDegree(int degree) {
    212         mDegree = degree;
    213         int count = getChildCount();
    214         for (int i = 0 ; i < count ; ++i) {
    215             View view = getChildAt(i);
    216             if (view instanceof RotateImageView) {
    217                 ((RotateImageView) view).setDegree(degree);
    218             }
    219         }
    220     }
    221 
    222     @Override
    223     public void setActivated(boolean activated) {
    224         super.setActivated(activated);
    225         mZoomIn.setActivated(activated);
    226         mZoomOut.setActivated(activated);
    227     }
    228 }
    229