Operation.java
/*
* Copyright 2022 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.processing;
import androidx.annotation.NonNull;
import androidx.annotation.WorkerThread;
import androidx.camera.core.ImageCaptureException;
import androidx.camera.core.impl.utils.executor.CameraXExecutors;
/**
* Operation that turns a single input image frame {@link I} to a output {@link O}.
*
* <p>Both the input {@link I} and the output {@link O} contain one or many camera frames and their
* metadata such as dimension, format and Exif.
*
* <p>This is a syntax sugar for the {@link Node} class. The purpose is for building a pipeline
* intuitively without using {@link Node}'s publisher/subscriber model.
*
* @param <I> input image frame
* @param <O> output image frame.
*/
public interface Operation<I, O> {
/**
* Processes an input frame and produces an output frame.
*
* <p>The implementation of method performs the image processing operations that usually
* blocks the current thread. It must be invoked on a non-blocking thread. e.g.
* {@link CameraXExecutors#ioExecutor()}.
*/
@NonNull
@WorkerThread
O apply(@NonNull I i) throws ImageCaptureException;
}