我使用相机api,拍摄的照片总是旋转90度,我想旋转它。
所以首先我想知道图片的方向,这一点我卡住了。
我总是在两个方面都不确定方向。
代码如下:
@Override
public void onPictureTaken(byte[] data, Camera camera) {
//Bitmap Options for lowering quality the bitmap to save memory
Options options = new BitmapFactory.Options();
options.inSampleSize = 4;
options.inPreferredConfig = Bitmap.Config.RGB_565;
//Make the bitmap
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, options);
//Making the path, the root will be fine for tests
String path = Environment.getExternalStorageDirectory().toString();
//output stream
OutputStream outputStream = null;
//Making the file as a jpg
File file = new File(path, "tmp_pic" + ".jpg"); // the File to save to
try {
//Writing the file
outputStream = new FileOutputStream(file);
outputStream.flush();
outputStream.close(); // do not forget to close the stream
//Getting the orientation in both possible ways
int ori = getOrientationFromExif(file.getPath());
int ori2 = getOrientationFromUri(Uri.fromFile(file));
}
catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
if (bitmap == null) {
Toast.makeText(getApplicationContext(), "Error: Cant make photo.", Toast.LENGTH_SHORT).show();
}
else {
PhotoTapView.photoViews.get(index).setPhotoImage(bitmap);
finish();
}
cameraObject.release();
}
定向功能:
//Getting orientation from file URI
private int getOrientationFromUri(Uri imageUri) {
String[] orientationColumn = { MediaStore.Images.Media.ORIENTATION };
Cursor cur = getContentResolver().query(imageUri, orientationColumn, null, null, null);
int orientation = -1;
if (cur != null && cur.moveToFirst()) {
orientation = cur.getInt(cur.getColumnIndex(orientationColumn[0]));
}
Log.i("Orientation from Uri", orientation + "");
return orientation;
}
//Getting orientation from ExifInterface
private static int getOrientationFromExif(String imagePath) {
int orientation = -1;
try {
ExifInterface exif = new ExifInterface(imagePath);
int exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
Log.i("Orientation from Exif: ", exifOrientation + "");
switch (exifOrientation) {
case ExifInterface.ORIENTATION_ROTATE_270:
orientation = 270;
Log.i("Orientation from Exif", "270");
break;
case ExifInterface.ORIENTATION_ROTATE_180:
orientation = 180;
Log.i("Orientation from Exif", "180");
break;
case ExifInterface.ORIENTATION_ROTATE_90:
Log.i("Orientation from Exif", "90");
orientation = 90;
break;
case ExifInterface.ORIENTATION_NORMAL:
orientation = 0;
Log.i("Orientation from Exif", "0 - Normal");
break;
case ExifInterface.ORIENTATION_UNDEFINED:
orientation = -1;
Log.e("Orientation from Exif", "UNDEFINED");
}
}
catch (IOException e) {}
return orientation;
}
日志输出:
01-14 19:46:09.468: E/Orientation from Exif(12411): UNDEFINED
01-14 19:46:09.468: I/Orientation from Uri(12411): -1
有什么问题吗?
最佳答案
我从2011年初就开始解码/观察android jpeg图像,因为我发布了一个图像查看应用程序。在“早期”的日子里,图像是按照传感器的本机方向编码的,设备的实际方向被写入exif元数据中。从2年前开始,我注意到方向不再写入exif数据,取而代之的是,camera应用程序在编码jpeg文件之前旋转图像像素。我的猜测是,这是因为一些照片查看器(*courk*windows*courk*)在显示jpeg文件时忽略exif方向,而不是等待微软修复它并指责android做错了什么,他们决定利用更快的CPU/内存,只需旋转图像。
结果是,在不知道exif方向的情况下,只能确定照片是以横向还是纵向拍摄的。这一点信息只是一个假设,因为大多数相机传感器的宽度比他们的高。