/*
* Copyright 2020 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 androidx.camera.view.preview.transform;
import android.view.Display;
import android.view.View;
import androidx.annotation.NonNull;
final class RotationTransform {
// Queries rotation value from view automatically.
static final int ROTATION_AUTOMATIC = -1;
private RotationTransform() {
}
/**
* Computes the rotation in degrees from its natural orientation.
*
* <p>When a application is running in remote display, the correct rotation degrees should
* be obtained from the device rotation. The rotation from the {@link View} may cause incorrect
* transform calculation results.
*
* @param view The {@link View} used to show the preview.
* @param deviceRotation The device rotation value provided by the developers.
* @return The rotation in degrees from its natural orientation.
*/
static float getRotationDegrees(@NonNull final View view, final int deviceRotation) {
if (deviceRotation != ROTATION_AUTOMATIC) {
return SurfaceRotation.rotationDegreesFromSurfaceRotation(deviceRotation);
} else {
return getRotationDegrees(view);
}
}
/** Computes the rotation of a {@link View} in degrees from its natural orientation. */
static float getRotationDegrees(@NonNull final View view) {
final Display display = view.getDisplay();
if (display == null) {
return 0;
}
final int rotation = display.getRotation();
return SurfaceRotation.rotationDegreesFromSurfaceRotation(rotation);
}
}