Files
app_Settings/src/com/android/settings/wifi/qrcode/QrCamera.java
Johnson Lu a558c01696 Integrate QrCode Camera with WifiDppQrCodeScannerFragment
Bug: 118797380
Test: RunSettingsRoboTests
Change-Id: I328bebbbcf44136df2c18ca1929a5da377a0cf6b
2018-12-01 09:03:39 +08:00

354 lines
13 KiB
Java

/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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.android.settings.wifi.qrcode;
import android.content.Context;
import android.graphics.Rect;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PreviewCallback;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.util.ArrayMap;
import android.util.Log;
import android.util.Size;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.WindowManager;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import androidx.annotation.VisibleForTesting;
/**
* Manage the camera for the QR scanner and help the decoder to get the image inside the scanning
* frame. Caller prepares a {@link SurfaceHolder} then call {@link #start(SurfaceHolder)} to
* start QR Code scanning. The scanning result will return by ScannerCallback interface. Caller
* can also call {@link #stop()} to halt QR Code scanning before the result returned.
*/
public class QrCamera extends Handler {
private static final String TAG = "QrCamera";
private static final int MSG_AUTO_FOCUS = 1;
private static double MIN_RATIO_DIFF_PERCENT = 0.1;
private static long AUTOFOCUS_INTERVAL_MS = 1500L;
private static Map<DecodeHintType, List<BarcodeFormat>> HINTS = new ArrayMap<>();
private static List<BarcodeFormat> FORMATS = new ArrayList<>();
static {
FORMATS.add(BarcodeFormat.QR_CODE);
HINTS.put(DecodeHintType.POSSIBLE_FORMATS, FORMATS);
}
private Camera mCamera;
private Size mPreviewSize;
private WeakReference<Context> mContext;
private ScannerCallback mScannerCallback;
private MultiFormatReader mReader;
private DecodingTask mDecodeTask;
private int mCameraOrientation;
private Camera.Parameters mParameters;
public QrCamera(Context context, ScannerCallback callback) {
mContext = new WeakReference<Context>(context);
mScannerCallback = callback;
mReader = new MultiFormatReader();
mReader.setHints(HINTS);
}
/**
* The function start camera preview and capture pictures to decode QR code continuously in a
* background task.
*
* @param surfaceHolder the Surface to be used for live preview, must already contain a surface
* when this method is called.
*/
public void start(SurfaceHolder surfaceHolder) {
if (mDecodeTask == null) {
mDecodeTask = new DecodingTask(surfaceHolder);
// Execute in the separate thread pool to prevent block other AsyncTask.
mDecodeTask.executeOnExecutor(Executors.newSingleThreadExecutor());
}
}
/**
* The function stop camera preview and background decode task. Caller call this function when
* the surface is being destroyed.
*/
public void stop() {
removeMessages(MSG_AUTO_FOCUS);
if (mDecodeTask != null) {
mDecodeTask.cancel(true);
mDecodeTask = null;
}
if (mCamera != null) {
mCamera.stopPreview();
}
}
/** The scanner which includes this QrCamera class should implement this */
public interface ScannerCallback {
/**
* The function used to handle the decoding result of the QR code.
*
* @param result the result QR code after decoding.
*/
void handleSuccessfulResult(String result);
/** Request the QR code scanner to handle the failure happened. */
void handleCameraFailure();
/**
* The function used to get the background View size.
*
* @return Includes the background view size.
*/
Size getViewSize();
/**
* The function used to get the frame position inside the view
*
* @param previewSize Is the preview size set by camera
* @param cameraOrientation Is the orientation of current Camera
* @return The rectangle would like to crop from the camera preview shot.
*/
Rect getFramePosition(Size previewSize, int cameraOrientation);
}
private void setCameraParameter() {
mParameters = mCamera.getParameters();
mPreviewSize = getBestPreviewSize(mParameters);
mParameters.setPreviewSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
mParameters.setPictureSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
if (mParameters.getSupportedFlashModes().contains(Parameters.FLASH_MODE_OFF)) {
mParameters.setFlashMode(Parameters.FLASH_MODE_OFF);
}
final List<String> supportedFocusModes = mParameters.getSupportedFocusModes();
if (supportedFocusModes.contains(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
mParameters.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
} else if (supportedFocusModes.contains(Parameters.FOCUS_MODE_AUTO)) {
mParameters.setFocusMode(Parameters.FOCUS_MODE_AUTO);
}
mCamera.setParameters(mParameters);
}
private boolean startPreview() {
if (mContext.get() == null) {
return false;
}
final WindowManager winManager =
(WindowManager) mContext.get().getSystemService(Context.WINDOW_SERVICE);
final int rotation = winManager.getDefaultDisplay().getRotation();
int degrees = 0;
switch (rotation) {
case Surface.ROTATION_0:
degrees = 0;
break;
case Surface.ROTATION_90:
degrees = 90;
break;
case Surface.ROTATION_180:
degrees = 180;
break;
case Surface.ROTATION_270:
degrees = 270;
break;
}
final int rotateDegrees = (mCameraOrientation - degrees + 360) % 360;
mCamera.setDisplayOrientation(rotateDegrees);
mCamera.startPreview();
if (mParameters.getFocusMode() == Parameters.FOCUS_MODE_AUTO) {
mCamera.autoFocus(/* Camera.AutoFocusCallback */ null);
sendMessageDelayed(obtainMessage(MSG_AUTO_FOCUS), AUTOFOCUS_INTERVAL_MS);
}
return true;
}
private class DecodingTask extends AsyncTask<Void, Void, String> {
private QrYuvLuminanceSource mImage;
private SurfaceHolder mSurfaceHolder;
private DecodingTask(SurfaceHolder surfaceHolder) {
mSurfaceHolder = surfaceHolder;
}
@Override
protected String doInBackground(Void... tmp) {
if (!initCamera(mSurfaceHolder)) {
return null;
}
final Semaphore imageGot = new Semaphore(0);
while (true) {
// This loop will try to capture preview image continuously until a valid QR Code
// decoded. The caller can also call {@link #stop()} to inturrupts scanning loop.
mCamera.setOneShotPreviewCallback(
(imageData, camera) -> {
mImage = getFrameImage(imageData);
imageGot.release();
});
try {
// Semaphore.acquire() blocking until permit is available, or the thread is
// interrupted.
imageGot.acquire();
Result qrCode = null;
try {
qrCode =
mReader.decodeWithState(
new BinaryBitmap(new HybridBinarizer(mImage)));
} catch (ReaderException e) {
// No logging since every time the reader cannot decode the
// image, this ReaderException will be thrown.
} finally {
mReader.reset();
}
if (qrCode != null) {
return qrCode.getText();
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
return null;
}
}
}
@Override
protected void onPostExecute(String qrCode) {
if (qrCode != null) {
mScannerCallback.handleSuccessfulResult(qrCode);
}
}
private boolean initCamera(SurfaceHolder surfaceHolder) {
final int numberOfCameras = Camera.getNumberOfCameras();
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
try {
for (int i = 0; i < numberOfCameras; ++i) {
Camera.getCameraInfo(i, cameraInfo);
if (cameraInfo.facing == CameraInfo.CAMERA_FACING_BACK) {
mCamera = Camera.open(i);
mCamera.setPreviewDisplay(surfaceHolder);
mCameraOrientation = cameraInfo.orientation;
break;
}
}
if (mCamera == null) {
Log.e(TAG, "Cannot find available back camera.");
mScannerCallback.handleCameraFailure();
return false;
}
setCameraParameter();
if (!startPreview()) {
Log.e(TAG, "Error to init Camera");
mCamera = null;
mScannerCallback.handleCameraFailure();
return false;
}
return true;
} catch (IOException e) {
Log.e(TAG, "Error to init Camera");
mCamera = null;
mScannerCallback.handleCameraFailure();
return false;
}
}
}
private QrYuvLuminanceSource getFrameImage(byte[] imageData) {
final Rect frame = mScannerCallback.getFramePosition(mPreviewSize, mCameraOrientation);
final Camera.Size size = mParameters.getPictureSize();
QrYuvLuminanceSource image = new QrYuvLuminanceSource(imageData, size.width, size.height);
return (QrYuvLuminanceSource)
image.crop(frame.left, frame.top, frame.width(), frame.height());
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_AUTO_FOCUS:
// Calling autoFocus(null) will only trigger the camera to focus once. In order
// to make the camera continuously auto focus during scanning, need to periodly
// trigger it.
mCamera.autoFocus(/* Camera.AutoFocusCallback */ null);
sendMessageDelayed(obtainMessage(MSG_AUTO_FOCUS), AUTOFOCUS_INTERVAL_MS);
break;
default:
Log.d(TAG, "Unexpected Message: " + msg.what);
}
}
/** Get best preview size from the list of camera supported preview sizes. Compares the
* preview size and aspect ratio to choose the best one. */
private Size getBestPreviewSize(Camera.Parameters parameters) {
final double minRatioDiffPercent = 0.1;
final Size windowSize = mScannerCallback.getViewSize();
final double winRatio = getRatio(windowSize.getWidth(), windowSize.getHeight());
double bestChoiceRatio = 0;
Size bestChoice = new Size(0, 0);
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
double ratio = getRatio(size.width, size.height);
if (size.height * size.width > bestChoice.getWidth() * bestChoice.getHeight()
&& (Math.abs(bestChoiceRatio - winRatio) / winRatio > minRatioDiffPercent
|| Math.abs(ratio - winRatio) / winRatio <= minRatioDiffPercent)) {
bestChoice = new Size(size.width, size.height);
bestChoiceRatio = getRatio(size.width, size.height);
}
}
return bestChoice;
}
private double getRatio(double x, double y) {
return (x < y) ? x / y : y / x;
}
@VisibleForTesting
protected void decodeImage(BinaryBitmap image) {
Result qrCode = null;
try {
qrCode = mReader.decodeWithState(image);
} catch (ReaderException e) {
} finally {
mReader.reset();
}
if (qrCode != null) {
mScannerCallback.handleSuccessfulResult(qrCode.getText());
}
}
}