java/com/android/incallui/answer/impl/classifier/LengthCountClassifier.java


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/*
 * Copyright (C) 2015 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 com.android.incallui.answer.impl.classifier;

/**
 * A classifier which looks at the ratio between the length of the stroke and its number of points.
 * The number of points is subtracted by 2 because the UP event comes in with some delay and it
 * should not influence the ratio and also strokes which are long and have a small number of points
 * are punished more (these kind of strokes are usually bad ones and they tend to score well in
 * other classifiers).
 */
class LengthCountClassifier extends StrokeClassifier {
  public LengthCountClassifier(ClassifierData classifierData) {}

  @Override
  public String getTag() {
    return "LEN_CNT";
  }

  @Override
  public float getFalseTouchEvaluation(Stroke stroke) {
    return LengthCountEvaluator.evaluate(
        stroke.getTotalLength() / Math.max(1.0f, stroke.getCount() - 2));
  }
}