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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.common.media;
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import android.annotation.TargetApi;
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import android.hardware.Camera;
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import android.os.Build;
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import android.os.Environment;
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import android.util.Log;
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import java.io.File;
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import java.text.SimpleDateFormat;
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import java.util.Date;
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import java.util.List;
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/**
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* Camera related utilities.
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*/
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public class CameraHelper {
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public static final int MEDIA_TYPE_IMAGE = 1;
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public static final int MEDIA_TYPE_VIDEO = 2;
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/**
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* Iterate over supported camera preview sizes to see which one best fits the
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* dimensions of the given view while maintaining the aspect ratio. If none can,
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* be lenient with the aspect ratio.
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*
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* @param sizes Supported camera preview sizes.
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* @param w The width of the view.
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* @param h The height of the view.
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* @return Best match camera preview size to fit in the view.
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*/
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public static Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
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// Use a very small tolerance because we want an exact match.
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final double ASPECT_TOLERANCE = 0.1;
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double targetRatio = (double) w / h;
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if (sizes == null)
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return null;
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Camera.Size optimalSize = null;
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// Start with max value and refine as we iterate over available preview sizes. This is the
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// minimum difference between view and camera height.
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double minDiff = Double.MAX_VALUE;
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// Target view height
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int targetHeight = h;
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// Try to find a preview size that matches aspect ratio and the target view size.
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// Iterate over all available sizes and pick the largest size that can fit in the view and
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// still maintain the aspect ratio.
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for (Camera.Size size : sizes) {
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double ratio = (double) size.width / size.height;
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if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
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continue;
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if (Math.abs(size.height - targetHeight) < minDiff) {
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optimalSize = size;
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minDiff = Math.abs(size.height - targetHeight);
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}
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}
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// Cannot find preview size that matches the aspect ratio, ignore the requirement
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if (optimalSize == null) {
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minDiff = Double.MAX_VALUE;
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for (Camera.Size size : sizes) {
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if (Math.abs(size.height - targetHeight) < minDiff) {
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optimalSize = size;
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minDiff = Math.abs(size.height - targetHeight);
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}
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}
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}
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return optimalSize;
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}
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/**
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* @return the default camera on the device. Return null if there is no camera on the device.
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*/
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public static Camera getDefaultCameraInstance() {
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return Camera.open();
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}
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/**
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* @return the default rear/back facing camera on the device. Returns null if camera is not
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* available.
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*/
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public static Camera getDefaultBackFacingCameraInstance() {
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return getDefaultCamera(Camera.CameraInfo.CAMERA_FACING_BACK);
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}
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/**
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* @return the default front facing camera on the device. Returns null if camera is not
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* available.
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*/
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public static Camera getDefaultFrontFacingCameraInstance() {
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return getDefaultCamera(Camera.CameraInfo.CAMERA_FACING_FRONT);
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}
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/**
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*
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* @param position Physical position of the camera i.e Camera.CameraInfo.CAMERA_FACING_FRONT
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* or Camera.CameraInfo.CAMERA_FACING_BACK.
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* @return the default camera on the device. Returns null if camera is not available.
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*/
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@TargetApi(Build.VERSION_CODES.GINGERBREAD)
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private static Camera getDefaultCamera(int position) {
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// Find the total number of cameras available
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int mNumberOfCameras = Camera.getNumberOfCameras();
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// Find the ID of the back-facing ("default") camera
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Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
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for (int i = 0; i < mNumberOfCameras; i++) {
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Camera.getCameraInfo(i, cameraInfo);
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if (cameraInfo.facing == position) {
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return Camera.open(i);
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}
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}
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return null;
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}
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/**
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* Creates a media file in the {@code Environment.DIRECTORY_PICTURES} directory. The directory
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* is persistent and available to other applications like gallery.
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*
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* @param type Media type. Can be video or image.
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* @return A file object pointing to the newly created file.
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*/
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public static File getOutputMediaFile(int type){
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// To be safe, you should check that the SDCard is mounted
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// using Environment.getExternalStorageState() before doing this.
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if (!Environment.getExternalStorageState().equalsIgnoreCase(Environment.MEDIA_MOUNTED)) {
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return null;
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}
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File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
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Environment.DIRECTORY_PICTURES), "CameraSample");
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// This location works best if you want the created images to be shared
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// between applications and persist after your app has been uninstalled.
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// Create the storage directory if it does not exist
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if (! mediaStorageDir.exists()){
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if (! mediaStorageDir.mkdirs()) {
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Log.d("CameraSample", "failed to create directory");
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return null;
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}
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}
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// Create a media file name
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String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
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File mediaFile;
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if (type == MEDIA_TYPE_IMAGE){
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mediaFile = new File(mediaStorageDir.getPath() + File.separator +
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"IMG_"+ timeStamp + ".jpg");
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} else if(type == MEDIA_TYPE_VIDEO) {
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mediaFile = new File(mediaStorageDir.getPath() + File.separator +
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"VID_"+ timeStamp + ".mp4");
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} else {
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return null;
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}
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return mediaFile;
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}
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}