| /* |
| * Copyright (C) 2017 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 android.support.transition; |
| |
| import android.graphics.Path; |
| import android.graphics.PathMeasure; |
| import android.graphics.PointF; |
| import android.util.Property; |
| |
| /** |
| * A special {@link Property} that can animate a pair of properties bi-dimensionally along the |
| * specified path. |
| * <p> |
| * This property should always be used with Animator that sets float fractions between |
| * {@code 0.f} and {@code 1.f}. For example, setting {@code 0.5f} to this property sets the |
| * values right in the middle of the specified path to the underlying properties. |
| * <p> |
| * Unlike many of the platform built-in properties, instances of this class cannot be reused |
| * for later animations. |
| */ |
| class PathProperty<T> extends Property<T, Float> { |
| |
| private final Property<T, PointF> mProperty; |
| private final PathMeasure mPathMeasure; |
| private final float mPathLength; |
| private final float[] mPosition = new float[2]; |
| private final PointF mPointF = new PointF(); |
| private float mCurrentFraction; |
| |
| PathProperty(Property<T, PointF> property, Path path) { |
| super(Float.class, property.getName()); |
| mProperty = property; |
| mPathMeasure = new PathMeasure(path, false); |
| mPathLength = mPathMeasure.getLength(); |
| } |
| |
| @Override |
| public Float get(T object) { |
| return mCurrentFraction; |
| } |
| |
| @Override |
| public void set(T target, Float fraction) { |
| mCurrentFraction = fraction; |
| mPathMeasure.getPosTan(mPathLength * fraction, mPosition, null); |
| mPointF.x = mPosition[0]; |
| mPointF.y = mPosition[1]; |
| mProperty.set(target, mPointF); |
| } |
| |
| } |