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      1 /*
      2  * Copyright (C) 2015 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.systemui.classifier;
     18 
     19 /**
     20  * A classifier which looks at the ratio between the length of the stroke and its number of
     21  * points. The number of points is subtracted by 2 because the UP event comes in with some delay
     22  * and it should not influence the ratio and also strokes which are long and have a small number
     23  * of points are punished more (these kind of strokes are usually bad ones and they tend to score
     24  * well in other classifiers).
     25  */
     26 public class LengthCountClassifier extends StrokeClassifier {
     27     public LengthCountClassifier(ClassifierData classifierData) {
     28     }
     29 
     30     @Override
     31     public String getTag() {
     32         return "LEN_CNT";
     33     }
     34 
     35     @Override
     36     public float getFalseTouchEvaluation(int type, Stroke stroke) {
     37         return LengthCountEvaluator.evaluate(stroke.getTotalLength()
     38                 / Math.max(1.0f, stroke.getCount() - 2));
     39     }
     40 }