1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.camera.one.v2.autofocus; 18 19 import android.hardware.camera2.CaptureRequest; 20 import android.hardware.camera2.CaptureResult; 21 22 import com.android.camera.async.Updatable; 23 import com.android.camera.one.v2.camera2proxy.CaptureResultProxy; 24 import com.google.common.base.Objects; 25 import com.google.common.collect.ImmutableSet; 26 import com.google.common.util.concurrent.SettableFuture; 27 28 import java.util.Set; 29 import java.util.concurrent.ExecutionException; 30 import java.util.concurrent.TimeUnit; 31 import java.util.concurrent.TimeoutException; 32 33 import javax.annotation.ParametersAreNonnullByDefault; 34 35 /** 36 * Listens for image metadata and returns the result of an AE scan caused by an 37 * AE_TRIGGER_START. The result of indicates whether flash is required. 38 * <p> 39 * Maintains the current state of auto-exposure scans resulting from explicit 40 * precapture trigger requests. This maintains the subset of the finite state 41 * machine of {@link CaptureResult#CONTROL_AE_STATE} which relates to 42 * CONTROL_AE_PRECAPTURE_TRIGGER 43 * <p> 44 * That is, it invokes the given callback when a scan is complete, according to 45 * the following sequence: 46 * 47 * <pre> 48 * .* CONTROL_AE_PRECAPTURE_TRIGGER_START .* 49 * (STATE_INACTIVE|STATE_FLASH_REQUIRED|STATE_CONVERGED|STATE_LOCKED) 50 * </pre> 51 * <p> 52 * See the android documentation for {@link CaptureResult#CONTROL_AE_STATE} for 53 * further documentation on the state machine this class implements. 54 */ 55 @ParametersAreNonnullByDefault 56 public final class AETriggerResult implements Updatable<CaptureResultProxy> { 57 private static final Set<Integer> TRIGGER_DONE_STATES = ImmutableSet.of( 58 CaptureResult.CONTROL_AE_STATE_INACTIVE, 59 CaptureResult.CONTROL_AE_STATE_FLASH_REQUIRED, 60 CaptureResult.CONTROL_AE_STATE_CONVERGED, 61 CaptureResult.CONTROL_AE_STATE_LOCKED); 62 63 private final TriggerStateMachine mStateMachine; 64 private final SettableFuture<Boolean> mFutureResult; 65 AETriggerResult()66 public AETriggerResult() { 67 mStateMachine = new TriggerStateMachine( 68 CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START, 69 TRIGGER_DONE_STATES); 70 mFutureResult = SettableFuture.create(); 71 } 72 73 @Override update(CaptureResultProxy result)74 public void update(CaptureResultProxy result) { 75 Integer state = result.get(CaptureResult.CONTROL_AE_STATE); 76 boolean done = mStateMachine.update( 77 result.getFrameNumber(), 78 result.getRequest().get(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER), 79 state); 80 if (done) { 81 boolean flashRequired = Objects.equal(state, CaptureResult 82 .CONTROL_AE_STATE_FLASH_REQUIRED); 83 mFutureResult.set(flashRequired); 84 } 85 } 86 87 /** 88 * Blocks until the AE scan is complete. 89 * 90 * @return Whether the scene requires flash to be properly exposed. 91 * @throws InterruptedException 92 */ get()93 public boolean get() throws InterruptedException { 94 try { 95 return mFutureResult.get(); 96 } catch (ExecutionException impossible) { 97 throw new RuntimeException(impossible); 98 } 99 } 100 101 /** 102 * Blocks until the AE scan is complete. 103 * 104 * @return Whether the scene requires flash to be properly exposed. 105 * @throws InterruptedException 106 */ get(long timeout, TimeUnit timeUnit)107 public boolean get(long timeout, TimeUnit timeUnit) throws InterruptedException, 108 TimeoutException { 109 try { 110 return mFutureResult.get(timeout, timeUnit); 111 } catch (ExecutionException impossible) { 112 throw new RuntimeException(impossible); 113 } 114 } 115 } 116