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/*
* Copyright (C) 2013 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.example.android.common.media;
import android.annotation.TargetApi;
import android.hardware.Camera;
import android.os.Build;
import android.os.Environment;
import android.util.Log;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
/**
* Camera related utilities.
*/
public class CameraHelper {
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
/**
* Iterate over supported camera preview sizes to see which one best fits the
* dimensions of the given view while maintaining the aspect ratio. If none can,
* be lenient with the aspect ratio.
*
* @param sizes Supported camera preview sizes.
* @param w The width of the view.
* @param h The height of the view.
* @return Best match camera preview size to fit in the view.
*/
public static Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
// Use a very small tolerance because we want an exact match.
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null)
return null;
Camera.Size optimalSize = null;
// Start with max value and refine as we iterate over available preview sizes. This is the
// minimum difference between view and camera height.
double minDiff = Double.MAX_VALUE;
// Target view height
int targetHeight = h;
// Try to find a preview size that matches aspect ratio and the target view size.
// Iterate over all available sizes and pick the largest size that can fit in the view and
// still maintain the aspect ratio.
for (Camera.Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
// Cannot find preview size that matches the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Camera.Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
/**
* @return the default camera on the device. Return null if there is no camera on the device.
*/
public static Camera getDefaultCameraInstance() {
return Camera.open();
}
/**
* @return the default rear/back facing camera on the device. Returns null if camera is not
* available.
*/
public static Camera getDefaultBackFacingCameraInstance() {
return getDefaultCamera(Camera.CameraInfo.CAMERA_FACING_BACK);
}
/**
* @return the default front facing camera on the device. Returns null if camera is not
* available.
*/
public static Camera getDefaultFrontFacingCameraInstance() {
return getDefaultCamera(Camera.CameraInfo.CAMERA_FACING_FRONT);
}
/**
*
* @param position Physical position of the camera i.e Camera.CameraInfo.CAMERA_FACING_FRONT
* or Camera.CameraInfo.CAMERA_FACING_BACK.
* @return the default camera on the device. Returns null if camera is not available.
*/
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
private static Camera getDefaultCamera(int position) {
// Find the total number of cameras available
int mNumberOfCameras = Camera.getNumberOfCameras();
// Find the ID of the back-facing ("default") camera
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
for (int i = 0; i < mNumberOfCameras; i++) {
Camera.getCameraInfo(i, cameraInfo);
if (cameraInfo.facing == position) {
return Camera.open(i);
}
}
return null;
}
/**
* Creates a media file in the {@code Environment.DIRECTORY_PICTURES} directory. The directory
* is persistent and available to other applications like gallery.
*
* @param type Media type. Can be video or image.
* @return A file object pointing to the newly created file.
*/
public static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
if (!Environment.getExternalStorageState().equalsIgnoreCase(Environment.MEDIA_MOUNTED)) {
return null;
}
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "CameraSample");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()) {
Log.d("CameraSample", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else if(type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_"+ timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
}
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