This problem was solved a long time ago but I encountered some difficulties to put all pieces together so here is my final solution, I hope this will help others :
public void startPreview() {
try {
Log.i(TAG, "starting preview: " + started);
// ....
Camera.CameraInfo camInfo = new Camera.CameraInfo();
Camera.getCameraInfo(cameraIndex, camInfo);
int cameraRotationOffset = camInfo.orientation;
// ...
Camera.Parameters parameters = camera.getParameters();
List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();
Camera.Size previewSize = null;
float closestRatio = Float.MAX_VALUE;
int targetPreviewWidth = isLandscape() ? getWidth() : getHeight();
int targetPreviewHeight = isLandscape() ? getHeight() : getWidth();
float targetRatio = targetPreviewWidth / (float) targetPreviewHeight;
Log.v(TAG, "target size: " + targetPreviewWidth + " / " + targetPreviewHeight + " ratio:" + targetRatio);
for (Camera.Size candidateSize : previewSizes) {
float whRatio = candidateSize.width / (float) candidateSize.height;
if (previewSize == null || Math.abs(targetRatio - whRatio) < Math.abs(targetRatio - closestRatio)) {
closestRatio = whRatio;
previewSize = candidateSize;
}
}
int rotation = getWindowManager().getDefaultDisplay().getRotation();
int degrees = 0;
switch (rotation) {
case Surface.ROTATION_0:
degrees = 0;
break; // Natural orientation
case Surface.ROTATION_90:
degrees = 90;
break; // Landscape left
case Surface.ROTATION_180:
degrees = 180;
break;// Upside down
case Surface.ROTATION_270:
degrees = 270;
break;// Landscape right
}
int displayRotation;
if (isFrontFacingCam) {
displayRotation = (cameraRotationOffset + degrees) % 360;
displayRotation = (360 - displayRotation) % 360; // compensate
// the
// mirror
} else { // back-facing
displayRotation = (cameraRotationOffset - degrees + 360) % 360;
}
Log.v(TAG, "rotation cam / phone = displayRotation: " + cameraRotationOffset + " / " + degrees + " = "
+ displayRotation);
this.camera.setDisplayOrientation(displayRotation);
int rotate;
if (isFrontFacingCam) {
rotate = (360 + cameraRotationOffset + degrees) % 360;
} else {
rotate = (360 + cameraRotationOffset - degrees) % 360;
}
Log.v(TAG, "screenshot rotation: " + cameraRotationOffset + " / " + degrees + " = " + rotate);
Log.v(TAG, "preview size: " + previewSize.width + " / " + previewSize.height);
parameters.setPreviewSize(previewSize.width, previewSize.height);
parameters.setRotation(rotate);
camera.setParameters(parameters);
camera.setPreviewDisplay(mHolder);
camera.startPreview();
Log.d(TAG, "preview started");
started = true;
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}