| /* |
| * Copyright (C) 2008 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.gesture.recognizer; |
| |
| import android.graphics.PointF; |
| |
| import com.android.gesture.Gesture; |
| |
| /** |
| * An instance represents a sample if the label is available or a query if |
| * the label is null. |
| */ |
| public class Instance { |
| |
| private final static float[] targetOrientations = { |
| 0, 45, 90, 135, 180, -0, -45, -90, -135, -180 |
| }; |
| |
| // the feature vector |
| public final float[] vector; |
| // the label can be null |
| public final String label; |
| // the length of the vector |
| public final float length; |
| // the id of the instance |
| public final long id; |
| |
| Instance(long d, float[] v, String l) { |
| id = d; |
| vector = v; |
| label = l; |
| float sum = 0; |
| for (int i = 0; i < vector.length; i++) { |
| sum += vector[i] * vector[i]; |
| } |
| length = (float)Math.sqrt(sum); |
| } |
| |
| public static Instance createInstance(Gesture gesture, String label) { |
| float[] pts = RecognitionUtil.resample(gesture, 64); |
| PointF center = RecognitionUtil.computeCentroid(pts); |
| float inductiveOrientation = (float)Math.atan2(pts[1] - center.y, |
| pts[0] - center.x); |
| inductiveOrientation *= 180 / Math.PI; |
| |
| float minDeviation = Float.MAX_VALUE; |
| for (int i=0; i<targetOrientations.length; i++) { |
| float delta = targetOrientations[i] - inductiveOrientation; |
| if (Math.abs(delta) < Math.abs(minDeviation)) { |
| minDeviation = delta; |
| } |
| } |
| |
| android.graphics.Matrix m = new android.graphics.Matrix(); |
| m.setTranslate(-center.x, -center.y); |
| android.graphics.Matrix rotation = new android.graphics.Matrix(); |
| rotation.setRotate(minDeviation); |
| m.postConcat(rotation); |
| m.mapPoints(pts); |
| |
| return new Instance(gesture.getID(), pts, label); |
| } |
| } |