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;
29 import java.io.IOException;
32 * This object wraps the Camera service object and expects to be the only one talking to it. The
33 * implementation encapsulates the steps needed to take preview-sized images, which are used for
34 * both preview and decoding.
36 final class CameraManager {
38 private static final String TAG = "CameraManager";
40 private static CameraManager mCameraManager;
41 private Camera mCamera;
42 private final Context mContext;
43 private Point mScreenResolution;
44 private Rect mFramingRect;
45 private Handler mPreviewHandler;
46 private int mPreviewMessage;
47 private Handler mAutoFocusHandler;
48 private int mAutoFocusMessage;
49 private boolean mPreviewing;
51 public static synchronized void init(Context context) {
52 if (mCameraManager == null) {
53 mCameraManager = new CameraManager(context);
54 mCameraManager.getScreenResolution();
58 public static CameraManager get() {
59 return mCameraManager;
62 private CameraManager(Context context) {
68 public void openDriver(SurfaceHolder holder) throws IOException {
69 // "throws IOException added to accommodate Android 1.5
70 if (mCamera == null) {
71 mCamera = Camera.open();
72 mCamera.setPreviewDisplay(holder);
73 setCameraParameters();
77 public void closeDriver() {
78 if (mCamera != null) {
84 public void startPreview() {
85 if (mCamera != null && !mPreviewing) {
86 mCamera.startPreview();
91 public void stopPreview() {
92 if (mCamera != null && mPreviewing) {
93 mCamera.setPreviewCallback(null);
94 mCamera.stopPreview();
95 mPreviewHandler = null;
96 mAutoFocusHandler = null;
102 * A single preview frame will be returned to the handler supplied. The data will arrive as
103 * byte[] in the message.obj field, with width and height encoded as message.arg1 and
104 * message.arg2, respectively.
106 * @param handler The handler to send the message to.
107 * @param message The what field of the message to be sent.
109 public void requestPreviewFrame(Handler handler, int message) {
110 if (mCamera != null && mPreviewing) {
111 mPreviewHandler = handler;
112 mPreviewMessage = message;
113 mCamera.setOneShotPreviewCallback(previewCallback);
117 public void requestAutoFocus(Handler handler, int message) {
118 if (mCamera != null && mPreviewing) {
119 mAutoFocusHandler = handler;
120 mAutoFocusMessage = message;
121 mCamera.autoFocus(autoFocusCallback);
126 * Calculates the framing rect which the UI should draw to show the user where to place the
127 * barcode. The actual captured image should be a bit larger than indicated because they might
128 * frame the shot too tightly. This target helps with alignment as well as forces the user to
129 * hold the device far enough away to ensure the image will be in focus.
131 * @return The rectangle to draw on screen in window coordinates.
133 public Rect getFramingRect() {
134 if (mFramingRect == null) {
135 int width = mScreenResolution.x;
136 int height = mScreenResolution.y * 3 / 4;
137 int leftOffset = (mScreenResolution.x - width) / 2;
138 int topOffset = (mScreenResolution.y - height) / 2;
139 mFramingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
145 * Preview frames are delivered here, which we pass on to the registered handler. Make sure to
146 * clear the handler so it will only receive one message.
148 private final Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
149 public void onPreviewFrame(byte[] data, Camera camera) {
150 if (mPreviewHandler != null) {
151 Message message = mPreviewHandler.obtainMessage(mPreviewMessage,
152 mScreenResolution.x, mScreenResolution.y, data);
153 message.sendToTarget();
154 mPreviewHandler = null;
159 private final Camera.AutoFocusCallback autoFocusCallback = new Camera.AutoFocusCallback() {
160 public void onAutoFocus(boolean success, Camera camera) {
161 if (mAutoFocusHandler != null) {
162 Message message = mAutoFocusHandler.obtainMessage(mAutoFocusMessage, success);
163 // The Barcodes app needs to insert a delay here because it does continuous focus,
164 // but this test app does not, so send the message immediately.
165 message.sendToTarget();
166 mAutoFocusHandler = null;
172 * Sets the camera up to take preview images which are used for both preview and decoding. We're
173 * counting on the default YUV420 semi-planar data. If that changes in the future, we'll need to
174 * specify it explicitly with setPreviewFormat().
176 private void setCameraParameters() {
177 Camera.Parameters parameters = mCamera.getParameters();
178 parameters.setPreviewSize(mScreenResolution.x, mScreenResolution.y);
179 mCamera.setParameters(parameters);
182 private Point getScreenResolution() {
183 if (mScreenResolution == null) {
184 WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
185 Display display = wm.getDefaultDisplay();
186 mScreenResolution = new Point(display.getWidth(), display.getHeight());
188 return mScreenResolution;