George Mount | d6107a3 | 2014-03-10 16:51:16 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2014 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 | package android.transition; |
| 17 | |
| 18 | import android.graphics.Rect; |
George Mount | d6107a3 | 2014-03-10 16:51:16 -0700 | [diff] [blame] | 19 | import android.view.View; |
| 20 | import android.view.ViewGroup; |
| 21 | |
| 22 | /** |
| 23 | * A propagation that varies with the distance to the epicenter of the Transition |
| 24 | * or center of the scene if no epicenter exists. When a View is visible in the |
| 25 | * start of the transition, Views farther from the epicenter will transition |
| 26 | * sooner than Views closer to the epicenter. When a View is not in the start |
| 27 | * of the transition or is not visible at the start of the transition, it will |
| 28 | * transition sooner when closer to the epicenter and later when farther from |
| 29 | * the epicenter. This is the default TransitionPropagation used with |
| 30 | * {@link android.transition.Explode}. |
| 31 | */ |
| 32 | public class CircularPropagation extends VisibilityPropagation { |
| 33 | private static final String TAG = "CircularPropagation"; |
| 34 | |
George Mount | 265f209 | 2014-04-30 16:24:53 -0700 | [diff] [blame] | 35 | private float mPropagationSpeed = 3.0f; |
George Mount | d6107a3 | 2014-03-10 16:51:16 -0700 | [diff] [blame] | 36 | |
| 37 | /** |
| 38 | * Sets the speed at which transition propagation happens, relative to the duration of the |
| 39 | * Transition. A <code>propagationSpeed</code> of 1 means that a View centered farthest from |
| 40 | * the epicenter and View centered at the epicenter will have a difference |
| 41 | * in start delay of approximately the duration of the Transition. A speed of 2 means the |
| 42 | * start delay difference will be approximately half of the duration of the transition. A |
| 43 | * value of 0 is illegal, but negative values will invert the propagation. |
| 44 | * |
| 45 | * @param propagationSpeed The speed at which propagation occurs, relative to the duration |
| 46 | * of the transition. A speed of 4 means it works 4 times as fast |
| 47 | * as the duration of the transition. May not be 0. |
| 48 | */ |
| 49 | public void setPropagationSpeed(float propagationSpeed) { |
| 50 | if (propagationSpeed == 0) { |
| 51 | throw new IllegalArgumentException("propagationSpeed may not be 0"); |
| 52 | } |
| 53 | mPropagationSpeed = propagationSpeed; |
| 54 | } |
| 55 | |
| 56 | @Override |
| 57 | public long getStartDelay(ViewGroup sceneRoot, Transition transition, |
| 58 | TransitionValues startValues, TransitionValues endValues) { |
| 59 | if (startValues == null && endValues == null) { |
| 60 | return 0; |
| 61 | } |
| 62 | int directionMultiplier = 1; |
| 63 | TransitionValues positionValues; |
| 64 | if (endValues == null || getViewVisibility(startValues) == View.VISIBLE) { |
| 65 | positionValues = startValues; |
| 66 | directionMultiplier = -1; |
| 67 | } else { |
| 68 | positionValues = endValues; |
| 69 | } |
| 70 | |
| 71 | int viewCenterX = getViewX(positionValues); |
| 72 | int viewCenterY = getViewY(positionValues); |
| 73 | |
| 74 | Rect epicenter = transition.getEpicenter(); |
| 75 | int epicenterX; |
| 76 | int epicenterY; |
| 77 | if (epicenter != null) { |
| 78 | epicenterX = epicenter.centerX(); |
| 79 | epicenterY = epicenter.centerY(); |
| 80 | } else { |
| 81 | int[] loc = new int[2]; |
| 82 | sceneRoot.getLocationOnScreen(loc); |
| 83 | epicenterX = Math.round(loc[0] + (sceneRoot.getWidth() / 2) |
| 84 | + sceneRoot.getTranslationX()); |
| 85 | epicenterY = Math.round(loc[1] + (sceneRoot.getHeight() / 2) |
| 86 | + sceneRoot.getTranslationY()); |
| 87 | } |
Neil Fuller | e573aa9 | 2015-02-11 15:49:47 +0000 | [diff] [blame] | 88 | double distance = distance(viewCenterX, viewCenterY, epicenterX, epicenterY); |
| 89 | double maxDistance = distance(0, 0, sceneRoot.getWidth(), sceneRoot.getHeight()); |
| 90 | double distanceFraction = distance/maxDistance; |
George Mount | d6107a3 | 2014-03-10 16:51:16 -0700 | [diff] [blame] | 91 | |
George Mount | 265f209 | 2014-04-30 16:24:53 -0700 | [diff] [blame] | 92 | long duration = transition.getDuration(); |
| 93 | if (duration < 0) { |
| 94 | duration = 300; |
| 95 | } |
| 96 | |
| 97 | return Math.round(duration * directionMultiplier / mPropagationSpeed * distanceFraction); |
George Mount | d6107a3 | 2014-03-10 16:51:16 -0700 | [diff] [blame] | 98 | } |
| 99 | |
Neil Fuller | e573aa9 | 2015-02-11 15:49:47 +0000 | [diff] [blame] | 100 | private static double distance(float x1, float y1, float x2, float y2) { |
| 101 | double x = x2 - x1; |
| 102 | double y = y2 - y1; |
| 103 | return Math.hypot(x, y); |
George Mount | d6107a3 | 2014-03-10 16:51:16 -0700 | [diff] [blame] | 104 | } |
| 105 | } |