| /* |
| * Copyright (C) 2010 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.animation; |
| |
| /** |
| * This evaluator can be used to perform type interpolation between integer |
| * values that represent ARGB colors. |
| */ |
| public class ArgbEvaluator implements TypeEvaluator { |
| |
| /** |
| * This function returns the calculated in-between value for a color |
| * given integers that represent the start and end values in the four |
| * bytes of the 32-bit int. Each channel is separately linearly interpolated |
| * and the resulting calculated values are recombined into the return value. |
| * |
| * @param fraction The fraction from the starting to the ending values |
| * @param startValue A 32-bit int value representing colors in the |
| * separate bytes of the parameter |
| * @param endValue A 32-bit int value representing colors in the |
| * separate bytes of the parameter |
| * @return A value that is calculated to be the linearly interpolated |
| * result, derived by separating the start and end values into separate |
| * color channels and interpolating each one separately, recombining the |
| * resulting values in the same way. |
| */ |
| public Object evaluate(float fraction, Object startValue, Object endValue) { |
| int startInt = (Integer) startValue; |
| int startA = (startInt >> 24); |
| int startR = (startInt >> 16) & 0xff; |
| int startG = (startInt >> 8) & 0xff; |
| int startB = startInt & 0xff; |
| |
| int endInt = (Integer) endValue; |
| int endA = (endInt >> 24); |
| int endR = (endInt >> 16) & 0xff; |
| int endG = (endInt >> 8) & 0xff; |
| int endB = endInt & 0xff; |
| |
| return (int)((startA + (int)(fraction * (endA - startA))) << 24) | |
| (int)((startR + (int)(fraction * (endR - startR))) << 16) | |
| (int)((startG + (int)(fraction * (endG - startG))) << 8) | |
| (int)((startB + (int)(fraction * (endB - startB)))); |
| } |
| } |