| /* |
| * Copyright (C) 2016 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.systemui.qs; |
| |
| import android.graphics.Path; |
| import android.view.animation.BaseInterpolator; |
| import android.view.animation.Interpolator; |
| |
| public class PathInterpolatorBuilder { |
| |
| // This governs how accurate the approximation of the Path is. |
| private static final float PRECISION = 0.002f; |
| |
| private float[] mX; // x coordinates in the line |
| private float[] mY; // y coordinates in the line |
| private float[] mDist; // Cumulative percentage length of the line |
| |
| public PathInterpolatorBuilder(Path path) { |
| initPath(path); |
| } |
| |
| public PathInterpolatorBuilder(float controlX, float controlY) { |
| initQuad(controlX, controlY); |
| } |
| |
| public PathInterpolatorBuilder(float controlX1, float controlY1, float controlX2, |
| float controlY2) { |
| initCubic(controlX1, controlY1, controlX2, controlY2); |
| } |
| |
| private void initQuad(float controlX, float controlY) { |
| Path path = new Path(); |
| path.moveTo(0, 0); |
| path.quadTo(controlX, controlY, 1f, 1f); |
| initPath(path); |
| } |
| |
| private void initCubic(float x1, float y1, float x2, float y2) { |
| Path path = new Path(); |
| path.moveTo(0, 0); |
| path.cubicTo(x1, y1, x2, y2, 1f, 1f); |
| initPath(path); |
| } |
| |
| private void initPath(Path path) { |
| float[] pointComponents = path.approximate(PRECISION); |
| |
| int numPoints = pointComponents.length / 3; |
| if (pointComponents[1] != 0 || pointComponents[2] != 0 |
| || pointComponents[pointComponents.length - 2] != 1 |
| || pointComponents[pointComponents.length - 1] != 1) { |
| throw new IllegalArgumentException("The Path must start at (0,0) and end at (1,1)"); |
| } |
| |
| mX = new float[numPoints]; |
| mY = new float[numPoints]; |
| mDist = new float[numPoints]; |
| float prevX = 0; |
| float prevFraction = 0; |
| int componentIndex = 0; |
| for (int i = 0; i < numPoints; i++) { |
| float fraction = pointComponents[componentIndex++]; |
| float x = pointComponents[componentIndex++]; |
| float y = pointComponents[componentIndex++]; |
| if (fraction == prevFraction && x != prevX) { |
| throw new IllegalArgumentException( |
| "The Path cannot have discontinuity in the X axis."); |
| } |
| if (x < prevX) { |
| throw new IllegalArgumentException("The Path cannot loop back on itself."); |
| } |
| mX[i] = x; |
| mY[i] = y; |
| if (i > 0) { |
| float dx = mX[i] - mX[i - 1]; |
| float dy = mY[i] - mY[i - 1]; |
| float dist = (float) Math.sqrt(dx * dx + dy * dy); |
| mDist[i] = mDist[i - 1] + dist; |
| } |
| prevX = x; |
| prevFraction = fraction; |
| } |
| // Scale down dist to 0-1. |
| float max = mDist[mDist.length - 1]; |
| for (int i = 0; i < numPoints; i++) { |
| mDist[i] /= max; |
| } |
| } |
| |
| public Interpolator getXInterpolator() { |
| return new PathInterpolator(mDist, mX); |
| } |
| |
| public Interpolator getYInterpolator() { |
| return new PathInterpolator(mDist, mY); |
| } |
| |
| private static class PathInterpolator extends BaseInterpolator { |
| private final float[] mX; // x coordinates in the line |
| private final float[] mY; // y coordinates in the line |
| |
| private PathInterpolator(float[] xs, float[] ys) { |
| mX = xs; |
| mY = ys; |
| } |
| |
| @Override |
| public float getInterpolation(float t) { |
| if (t <= 0) { |
| return 0; |
| } else if (t >= 1) { |
| return 1; |
| } |
| // Do a binary search for the correct x to interpolate between. |
| int startIndex = 0; |
| int endIndex = mX.length - 1; |
| |
| while (endIndex - startIndex > 1) { |
| int midIndex = (startIndex + endIndex) / 2; |
| if (t < mX[midIndex]) { |
| endIndex = midIndex; |
| } else { |
| startIndex = midIndex; |
| } |
| } |
| |
| float xRange = mX[endIndex] - mX[startIndex]; |
| if (xRange == 0) { |
| return mY[startIndex]; |
| } |
| |
| float tInRange = t - mX[startIndex]; |
| float fraction = tInRange / xRange; |
| |
| float startY = mY[startIndex]; |
| float endY = mY[endIndex]; |
| return startY + (fraction * (endY - startY)); |
| } |
| } |
| |
| } |