How to rotate and flip bitmap in onPictureTaken
android
Solution
I have put a lot of work into this and thought, I'd share my solution. It is tested on a Motorola Devy, Samsung Xcover 1 and Samsung XCover 2.
As I work with a custom camera preview, the solution basically has two parts. 1. Take care of the camera preview and set rotation of the preview according to device rotation. 2. Once a picture is taken, that is the 'onPictureTaken' callback is invoked rotate the picture by the correct angle, such that it shows what the preview just showed.
1
private void initPreview(int width, int height) {
if (camera != null && holder.getSurface() != null) {
try {
camera.setPreviewDisplay(holder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Toast.makeText(getContext(), t.getMessage(),
Toast.LENGTH_LONG).show();
}
try {
Camera.Parameters parameters=camera.getParameters();
Camera.Size size=getBestPreviewSize(width, height, parameters);
Camera.Size pictureSize=getSmallestPictureSize(parameters);
Display display = windowManager.getDefaultDisplay();
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.FROYO) { // for 2.1 and before
if (isPortrait(display)) {
parameters.set(CAMERA_PARAM_ORIENTATION, CAMERA_PARAM_PORTRAIT);
} else {
parameters.set(CAMERA_PARAM_ORIENTATION, CAMERA_PARAM_LANDSCAPE);
}
} else { // for 2.2 and later
switch (display.getRotation()) {
case Surface.ROTATION_0: // This is display orientation
if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
else parameters.setPreviewSize(size.width, size.height);
camera.setDisplayOrientation(90);
break;
case Surface.ROTATION_90:
if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
else parameters.setPreviewSize(size.width, size.height);
camera.setDisplayOrientation(0);
break;
case Surface.ROTATION_180:
if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
else parameters.setPreviewSize(size.width, size.height);
camera.setDisplayOrientation(270);
break;
case Surface.ROTATION_270:
if (size.height > size.width) parameters.setPreviewSize(size.height, size.width);
else parameters.setPreviewSize(size.width, size.height);
camera.setDisplayOrientation(180);
break;
}
}
parameters.setPictureSize(pictureSize.width, pictureSize.height);
//parameters.setPictureFormat(ImageFormat.JPEG);
camera.setParameters(parameters);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Your 'surfaceChanged' method, in your camera preview (SurfaceView), you should look like this:
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
stopPreview();
initPreview(w, h);
startPreview();
}
where
stopPreview:
private void stopPreview() {
if (camera != null) {
camera.stopPreview();
}
}
startPreview:
private void startPreview() {
if (camera != null) {
camera.startPreview();
}
}
2
In your 'onPictureTaken' callback rotate the picture, using the following code:
Display display = getWindowManager().getDefaultDisplay();
int rotation = 0;
switch (display.getRotation()) {
case Surface.ROTATION_0: // This is display orientation
rotation = 90;
break;
case Surface.ROTATION_90:
rotation = 0;
break;
case Surface.ROTATION_180:
rotation = 270;
break;
case Surface.ROTATION_270:
rotation = 180;
break;
}
Bitmap bitmap = BitmapTools.toBitmap(data);
bitmap = BitmapTools.rotate(bitmap, rotation);
BitmapTools.java
public class BitmapTools {
public static Bitmap toBitmap(byte[] data) {
return BitmapFactory.decodeByteArray(data , 0, data.length);
}
public static Bitmap rotate(Bitmap in, int angle) {
Matrix mat = new Matrix();
mat.postRotate(angle);
return Bitmap.createBitmap(in, 0, 0, in.getWidth(), in.getHeight(), mat, true);
}
}
Problem
I'm finding in `onPictureTaken` that the bitmap saved is mirrored about the y-axis and rotated 90 degrees clockwise even though the camera preview was not. This is on my Nexus S that's running 2.3.6. The same program running on my Nexus 4 with 4.2 has the resulting bitmap mirrored about the y-axis and rotated 180 degrees clockwise. This is the code I'm running in `onPictureTaken`: ``` @Override public void onPictureTaken(final byte[] data, Camera camera) { Bitmap picture = BitmapFactory.decodeByteArray(data, 0, data.length); String path = MediaStore.Images.Media.insertImage(getContentResolver(), picture, "name" , "description"); Log.e("tag", "path: " + path); // prints something like "path: content://media/external/images/media/819" try { ExifInterface exif = new ExifInterface(path); // prints this error: "04-25 21:28:21.063: E/JHEAD(12201): can't open 'content://media/external/images/media/819'" int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL); Log.e("tag", "exif orientation: " + orientation); // this is outputting orientation unknown } catch (IOException e) { e.printStackTrace(); } } ``` Can anyone show me how I rectify this given that I seem to be getting different results from different devices? How do I detect the orientation of the resulting bitmap so that I know to rotate it either 90 or 180 degrees counterclockwise? [EDIT] I added some more information using the ExifInterface stuff I've been reading about, but that information doesn't seem to pan out...