package com.zxing.camera;
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import android.annotation.SuppressLint;
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import android.content.Context;
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import android.hardware.Camera;
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import android.os.AsyncTask;
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import android.util.Log;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.concurrent.RejectedExecutionException;
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public class AutoFocusManager implements Camera.AutoFocusCallback {
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private static final String TAG = AutoFocusManager.class.getSimpleName();
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private static final long AUTO_FOCUS_INTERVAL_MS = 1800L;
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private static final Collection<String> FOCUS_MODES_CALLING_AF;
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static {
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FOCUS_MODES_CALLING_AF = new ArrayList<String>(2);
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FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_AUTO);
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FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_MACRO);
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}
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private final boolean useAutoFocus;
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private final Camera camera;
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private boolean stopped;
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private boolean focusing;
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private AsyncTask<?, ?, ?> outstandingTask;
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public AutoFocusManager(Context context, Camera camera) {
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this.camera = camera;
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String currentFocusMode = camera.getParameters().getFocusMode();
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useAutoFocus = FOCUS_MODES_CALLING_AF.contains(currentFocusMode);
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Log.i(TAG, "Current focus mode '" + currentFocusMode + "'; use auto focus? " + useAutoFocus);
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start();
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}
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@Override
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public synchronized void onAutoFocus(boolean success, Camera theCamera) {
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focusing = false;
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autoFocusAgainLater();
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}
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@SuppressLint("NewApi")
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private synchronized void autoFocusAgainLater() {
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if (!stopped && outstandingTask == null) {
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AutoFocusTask newTask = new AutoFocusTask();
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try {
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newTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
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outstandingTask = newTask;
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} catch (RejectedExecutionException ree) {
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Log.w(TAG, "Could not request auto focus", ree);
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}
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}
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}
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public synchronized void start() {
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if (useAutoFocus) {
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outstandingTask = null;
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if (!stopped && !focusing) {
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try {
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camera.autoFocus(this);
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focusing = true;
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} catch (RuntimeException re) {
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// Have heard RuntimeException reported in Android 4.0.x+;
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// continue?
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Log.w(TAG, "Unexpected exception while focusing", re);
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// Try again later to keep cycle going
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autoFocusAgainLater();
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}
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}
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}
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}
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private synchronized void cancelOutstandingTask() {
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if (outstandingTask != null) {
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if (outstandingTask.getStatus() != AsyncTask.Status.FINISHED) {
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outstandingTask.cancel(true);
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}
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outstandingTask = null;
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}
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}
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public synchronized void stop() {
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stopped = true;
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if (useAutoFocus) {
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cancelOutstandingTask();
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// Doesn't hurt to call this even if not focusing
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try {
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camera.cancelAutoFocus();
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} catch (RuntimeException re) {
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// Have heard RuntimeException reported in Android 4.0.x+;
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// continue?
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Log.w(TAG, "Unexpected exception while cancelling focusing", re);
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}
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}
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}
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private final class AutoFocusTask extends AsyncTask<Object, Object, Object> {
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@Override
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protected Object doInBackground(Object... voids) {
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try {
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Thread.sleep(AUTO_FOCUS_INTERVAL_MS);
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} catch (InterruptedException e) {
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// continue
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}
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start();
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return null;
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}
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}
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}
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