2 * Copyright (C) 2008 ZXing authors
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 package com.google.zxing.client.androidtest;
19 import android.content.Context;
20 import android.graphics.Point;
21 import android.graphics.Rect;
22 import android.hardware.Camera;
23 import android.os.Handler;
24 import android.os.Message;
25 import android.view.Display;
26 import android.view.SurfaceHolder;
27 import android.view.WindowManager;
30 * This object wraps the Camera service object and expects to be the only one talking to it. The
31 * implementation encapsulates the steps needed to take preview-sized images, which are used for
32 * both preview and decoding.
34 final class CameraManager {
36 private static final String TAG = "CameraManager";
38 private static CameraManager mCameraManager;
39 private Camera mCamera;
40 private final Context mContext;
41 private Point mScreenResolution;
42 private Rect mFramingRect;
43 private Handler mPreviewHandler;
44 private int mPreviewMessage;
45 private Handler mAutoFocusHandler;
46 private int mAutoFocusMessage;
47 private boolean mPreviewing;
49 public static void init(Context context) {
50 if (mCameraManager == null) {
51 mCameraManager = new CameraManager(context);
52 mCameraManager.getScreenResolution();
56 public static CameraManager get() {
57 return mCameraManager;
60 private CameraManager(Context context) {
66 public void openDriver(SurfaceHolder holder) {
67 if (mCamera == null) {
68 mCamera = Camera.open();
69 mCamera.setPreviewDisplay(holder);
71 setCameraParameters();
75 public void closeDriver() {
76 if (mCamera != null) {
82 public void startPreview() {
83 if (mCamera != null && !mPreviewing) {
84 mCamera.startPreview();
89 public void stopPreview() {
90 if (mCamera != null && mPreviewing) {
91 mCamera.setPreviewCallback(null);
92 mCamera.stopPreview();
93 mPreviewHandler = null;
94 mAutoFocusHandler = null;
100 * A single preview frame will be returned to the handler supplied. The data will arrive as
101 * byte[] in the message.obj field, with width and height encoded as message.arg1 and
102 * message.arg2, respectively.
104 * @param handler The handler to send the message to.
105 * @param message The what field of the message to be sent.
107 public void requestPreviewFrame(Handler handler, int message) {
108 if (mCamera != null && mPreviewing) {
109 mPreviewHandler = handler;
110 mPreviewMessage = message;
111 mCamera.setPreviewCallback(previewCallback);
115 public void requestAutoFocus(Handler handler, int message) {
116 if (mCamera != null && mPreviewing) {
117 mAutoFocusHandler = handler;
118 mAutoFocusMessage = message;
119 mCamera.autoFocus(autoFocusCallback);
124 * Calculates the framing rect which the UI should draw to show the user where to place the
125 * barcode. The actual captured image should be a bit larger than indicated because they might
126 * frame the shot too tightly. This target helps with alignment as well as forces the user to
127 * hold the device far enough away to ensure the image will be in focus.
129 * @return The rectangle to draw on screen in window coordinates.
131 public Rect getFramingRect() {
132 if (mFramingRect == null) {
133 int size = ((mScreenResolution.x < mScreenResolution.y) ? mScreenResolution.x :
134 mScreenResolution.y) * 3 / 4;
135 int leftOffset = (mScreenResolution.x - size) / 2;
136 int topOffset = (mScreenResolution.y - size) / 2;
137 mFramingRect = new Rect(leftOffset, topOffset, leftOffset + size, topOffset + size);
143 * Preview frames are delivered here, which we pass on to the registered handler. Make sure to
144 * clear the handler so it will only receive one message.
146 private final Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
147 public void onPreviewFrame(byte[] data, Camera camera) {
148 camera.setPreviewCallback(null);
149 if (mPreviewHandler != null) {
150 Message message = mPreviewHandler.obtainMessage(mPreviewMessage,
151 mScreenResolution.x, mScreenResolution.y, data);
152 message.sendToTarget();
153 mPreviewHandler = null;
158 private final Camera.AutoFocusCallback autoFocusCallback = new Camera.AutoFocusCallback() {
159 public void onAutoFocus(boolean success, Camera camera) {
160 if (mAutoFocusHandler != null) {
161 Message message = mAutoFocusHandler.obtainMessage(mAutoFocusMessage, success);
162 // The Barcodes app needs to insert a delay here because it does continuous focus,
163 // but this test app does not, so send the message immediately.
164 message.sendToTarget();
165 mAutoFocusHandler = null;
171 * Sets the camera up to take preview images which are used for both preview and decoding. We're
172 * counting on the default YUV420 semi-planar data. If that changes in the future, we'll need to
173 * specify it explicitly with setPreviewFormat().
175 private void setCameraParameters() {
176 Camera.Parameters parameters = mCamera.getParameters();
177 parameters.setPreviewSize(mScreenResolution.x, mScreenResolution.y);
178 mCamera.setParameters(parameters);
181 private Point getScreenResolution() {
182 if (mScreenResolution == null) {
183 WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
184 Display display = wm.getDefaultDisplay();
185 mScreenResolution = new Point(display.getWidth(), display.getHeight());
187 return mScreenResolution;