In my app, I take pictures from an overhead perspective, where the phone tends to be essentially flat, like you would for documents and stuff. For several days now, I have been freaking out, trying to understand why the Android app tends to zoom in when taking the picture, but mostly only when the device was moved to landscape orientation before really lining up the shot. Finally, I think I have found the reason. In the CameraBase.kt, there is this orientation handler:
private val orientationEventListener = object : OrientationEventListener(context) {
override fun onOrientationChanged(orientation: Int) {
if (rotation == CameraOrientation.UNKNOWN) {
val newOrientation = when (orientation) {
in 45 until 135 -> 270
in 135 until 225 -> 180
in 225 until 315 -> 90
else -> 0
}
if (newOrientation != currentOrientation) {
currentOrientation = newOrientation
orientationUpdated()
}
}
}
}
After setting up an OrientationEventListener in another part of my app so I can see what is going on, I found that in landscape mode the value tended to be like
but as the phone approaches flatness, the value changes to
JS: OOOOOOORIENT -1
So what effectively happens in my app is, the phone is in landscape and the camera plus is ready to go with a 16:9 ratio and an image size of 3840x2160. The orientation handler is returning 90 at this point. But then the phone moves flat and the orientation handler starts emitting 0 because of the -1 orientation value, which changes the imageCapture?.targetRotation even though it really should not have changed.
If this line
if (rotation == CameraOrientation.UNKNOWN) {
was changed to
if (orientation > -1) {
then everything would be perfect. I think that fits logically with what should be happening (and maybe it is the original intent of that if statement?), i.e. if the orientation is unknown (-1), then don't update the targetRotation for the image capture.
sublime392
commented
1 year ago
In my app, I take pictures from an overhead perspective, where the phone tends to be essentially flat, like you would for documents and stuff. For several days now, I have been freaking out, trying to understand why the Android app tends to zoom in when taking the picture, but mostly only when the device was moved to landscape orientation before really lining up the shot. Finally, I think I have found the reason. In the CameraBase.kt, there is this orientation handler:
After setting up an OrientationEventListener in another part of my app so I can see what is going on, I found that in landscape mode the value tended to be like
but as the phone approaches flatness, the value changes to
So what effectively happens in my app is, the phone is in landscape and the camera plus is ready to go with a 16:9 ratio and an image size of 3840x2160. The orientation handler is returning 90 at this point. But then the phone moves flat and the orientation handler starts emitting 0 because of the -1 orientation value, which changes the
imageCapture?.targetRotationeven though it really should not have changed.If this line
was changed to
then everything would be perfect. I think that fits logically with what should be happening (and maybe it is the original intent of that if statement?), i.e. if the orientation is unknown (-1), then don't update the targetRotation for the image capture.