CameraFilter.java
/*
* 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.core;
import androidx.annotation.NonNull;
import androidx.annotation.RestrictTo;
import androidx.camera.core.impl.CameraConfig;
import androidx.camera.core.impl.ExtendedCameraConfigProviderStore;
import com.google.auto.value.AutoValue;
import java.util.List;
/**
* An interface for filtering cameras.
*/
public interface CameraFilter {
/**
* Filters a list of {@link CameraInfo}s and returns those matching the requirements.
*
* <p>If the output list contains CameraInfos not in the input list, when used by a
* {@link androidx.camera.core.CameraSelector} then it will result in an
* IllegalArgumentException thrown when calling bindToLifecycle.
*
* <p>The CameraInfo that has lower index in the list has higher priority. When used by
* {@link androidx.camera.core.CameraSelector.Builder#addCameraFilter(CameraFilter)}, the
* available cameras will be filtered by all {@link CameraFilter}s by the order they were
* added. The first camera in the result will be selected if there are multiple cameras left.
*
* @param cameraInfos An unmodifiable list of {@link CameraInfo}s being filtered.
* @return The output list of {@link CameraInfo}s that match the requirements. Users are
* expected to create a new list to return with.
*/
@NonNull
List<CameraInfo> filter(@NonNull List<CameraInfo> cameraInfos);
/**
* Returns the id of this camera filter.
*
* @hide
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
@NonNull
default Id getId() {
return Id.DEFAULT;
}
/**
* An identifier for a {@link CameraFilter}.
*
* <p>A camera filter can be associated with a set of camera configuration options. This
* means a camera filter's {@link Id} can be mapped to a unique {@link CameraConfig}. An
* example of this is extension modes, where a camera filter can represent an extension mode,
* and each extension mode adds a set of camera configurations to the camera that supports it
* . {@link ExtendedCameraConfigProviderStore#getConfigProvider(Object)} allows retrieving the
* {@link CameraConfig} of an extension mode given the {@link CameraFilter.Id} of its camera
* filter.
*
* <p>The {@link Id} class allows anything to be wrapped as an {@link Id} instance. The
* caller should make the input value object unique when calling the {@link #create(Object)}
* function. So that the {@link Id} can be recognized and used for specific purposes.
*
* @hide
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
@AutoValue
abstract class Id {
public static final Id DEFAULT = create(new Object());
@NonNull
public static Id create(@NonNull Object value) {
return new AutoValue_CameraFilter_Id(value);
}
@NonNull
public abstract Object getValue();
}
}