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
17package com.android.camera.ui;
18
19import com.android.camera.R;
20
21import android.content.Context;
22import android.os.Handler;
23import android.util.AttributeSet;
24import android.view.View;
25import android.widget.ImageView;
26import 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 */
32public 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