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 {
LengthCountClassifier(ClassifierData classifierData)27     public LengthCountClassifier(ClassifierData classifierData) {
28     }
29 
30     @Override
getTag()31     public String getTag() {
32         return "LEN_CNT";
33     }
34 
35     @Override
getFalseTouchEvaluation(int type, Stroke stroke)36     public float getFalseTouchEvaluation(int type, Stroke stroke) {
37         return LengthCountEvaluator.evaluate(stroke.getTotalLength()
38                 / Math.max(1.0f, stroke.getCount() - 2));
39     }
40 }