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/*
* Copyright (C) 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.client.android;
import com.google.zxing.ResultPoint;
import android.content.Context;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Display;
import android.view.SurfaceHolder;
import android.view.WindowManager;
import java.io.IOException;
/**
* This object wraps the Camera service object and expects to be the only one talking to it. The
* implementation encapsulates the steps needed to take preview-sized images, which are used for
* both preview and decoding.
*/
final class CameraManager {
private static final String TAG = "CameraManager";
private static CameraManager mCameraManager;
private Camera mCamera;
private final Context mContext;
private Point mScreenResolution;
private Rect mFramingRect;
private Handler mPreviewHandler;
private int mPreviewMessage;
private Handler mAutoFocusHandler;
private int mAutoFocusMessage;
private boolean mInitialized;
private boolean mPreviewing;
public static void init(Context context) {
if (mCameraManager == null) {
mCameraManager = new CameraManager(context);
}
}
public static CameraManager get() {
return mCameraManager;
}
private CameraManager(Context context) {
mContext = context;
mCamera = null;
mInitialized = false;
mPreviewing = false;
}
public void openDriver(SurfaceHolder holder) throws IOException {
if (mCamera == null) {
mCamera = Camera.open();
mCamera.setPreviewDisplay(holder);
if (!mInitialized) {
mInitialized = true;
getScreenResolution();
}
setCameraParameters();
}
}
public void closeDriver() {
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
public void startPreview() {
if (mCamera != null && !mPreviewing) {
mCamera.startPreview();
mPreviewing = true;
}
}
public void stopPreview() {
if (mCamera != null && mPreviewing) {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();
mPreviewHandler = null;
mAutoFocusHandler = null;
mPreviewing = false;
}
}
/**
* A single preview frame will be returned to the handler supplied. The data will arrive as byte[]
* in the message.obj field, with width and height encoded as message.arg1 and message.arg2,
* respectively.
*
* @param handler The handler to send the message to.
* @param message The what field of the message to be sent.
*/
public void requestPreviewFrame(Handler handler, int message) {
if (mCamera != null && mPreviewing) {
mPreviewHandler = handler;
mPreviewMessage = message;
mCamera.setOneShotPreviewCallback(previewCallback);
}
}
public void requestAutoFocus(Handler handler, int message) {
if (mCamera != null && mPreviewing) {
mAutoFocusHandler = handler;
mAutoFocusMessage = message;
mCamera.autoFocus(autoFocusCallback);
}
}
/**
* Calculates the framing rect which the UI should draw to show the user where to place the
* barcode. The actual captured image should be a bit larger than indicated because they might
* frame the shot too tightly. This target helps with alignment as well as forces the user to hold
* the device far enough away to ensure the image will be in focus.
*
* @return The rectangle to draw on screen in window coordinates.
*/
public Rect getFramingRect() {
if (mFramingRect == null) {
int size = (mScreenResolution.x < mScreenResolution.y ? mScreenResolution.x :
mScreenResolution.y) * 3 / 4;
int leftOffset = (mScreenResolution.x - size) / 2;
int topOffset = (mScreenResolution.y - size) / 2;
mFramingRect = new Rect(leftOffset, topOffset, leftOffset + size, topOffset + size);
Log.v(TAG, "Calculated framing rect: " + mFramingRect);
}
return mFramingRect;
}
/**
* Converts the result points from still resolution coordinates to screen coordinates.
*
* @param points The points returned by the Reader subclass through Result.getResultPoints().
* @return An array of Points scaled to the size of the framing rect and offset appropriately
* so they can be drawn in screen coordinates.
*/
public Point[] convertResultPoints(ResultPoint[] points) {
Rect frame = getFramingRect();
int count = points.length;
Point[] output = new Point[count];
for (int x = 0; x < count; x++) {
output[x] = new Point();
output[x].x = frame.left + (int) (points[x].getX() + 0.5f);
output[x].y = frame.top + (int) (points[x].getY() + 0.5f);
}
return output;
}
/**
* Preview frames are delivered here, which we pass on to the registered handler. Make sure to
* clear the handler so it will only receive one message.
*/
private final Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera camera) {
if (mPreviewHandler != null) {
Message message = mPreviewHandler.obtainMessage(mPreviewMessage, mScreenResolution.x,
mScreenResolution.y, data);
message.sendToTarget();
mPreviewHandler = null;
}
}
};
private final Camera.AutoFocusCallback autoFocusCallback = new Camera.AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {
if (mAutoFocusHandler != null) {
Message message = mAutoFocusHandler.obtainMessage(mAutoFocusMessage, success);
// Simulate continuous autofocus by sending a focus request every 1.5 seconds.
mAutoFocusHandler.sendMessageDelayed(message, 1500L);
mAutoFocusHandler = null;
}
}
};
/**
* Sets the camera up to take preview images which are used for both preview and decoding. We're
* counting on the default YUV420 semi-planar data. If that changes in the future, we'll need to
* specify it explicitly with setPreviewFormat().
*/
private void setCameraParameters() {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mScreenResolution.x, mScreenResolution.y);
// FIXME: This is a hack to turn the flash off on the Samsung Galaxy. In the future there
// will hopefully be a standard setting like "off" that all devices will honor.
parameters.set("flash-mode", "2");
mCamera.setParameters(parameters);
Log.v(TAG, "Setting params for preview: width " + mScreenResolution.x + " height " +
mScreenResolution.y);
}
private Point getScreenResolution() {
if (mScreenResolution == null) {
WindowManager manager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
Display display = manager.getDefaultDisplay();
mScreenResolution = new Point(display.getWidth(), display.getHeight());
}
return mScreenResolution;
}
}
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