content: /*
   * Copyright (C) 2019 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 androidx.motionlayout.cycleEditor;
  
  /**
   * This performs a simple linear interpolation in multiple dimensions
   */
  public class LinearInterpolator extends Interpolator {
  
      private static final String TAG = "LinearInterpolator";
      private double[] mT;
      private double[][] mY;
  
      public LinearInterpolator(double[] time, double[][] y) {
          final int N = time.length;
          final int dim = y[0].length;
          mT = time;
          mY = y;
      }
  
      public void getPos(double t, double[] v) {
          final int n = mT.length;
          final int dim = mY[0].length;
          if (t <= mT[0]) {
              for (int j = 0; j < dim; j++) {
                  v[j] = mY[0][j];
              }
              return;
          }
          if (t >= mT[n - 1]) {
              for (int j = 0; j < dim; j++) {
                  v[j] = mY[n - 1][j];
              }
              return;
          }
  
          for (int i = 0; i < n - 1; i++) {
              if (t == mT[i]) {
                  for (int j = 0; j < dim; j++) {
                      v[j] = mY[i][j];
                  }
              }
              if (t < mT[i + 1]) {
                  double h = mT[i + 1] - mT[i];
                  double x = (t - mT[i]) / h;
                  for (int j = 0; j < dim; j++) {
                      double y1 = mY[i][j];
                      double y2 = mY[i + 1][j];
  
                      v[j] = y1 * (1 - x) + y2 * x;
                  }
                  return;
              }
          }
      }
  
      public void getPos(double t, float[] v) {
          final int n = mT.length;
          final int dim = mY[0].length;
          if (t <= mT[0]) {
              for (int j = 0; j < dim; j++) {
                  v[j] = (float) mY[0][j];
              }
              return;
          }
          if (t >= mT[n - 1]) {
              for (int j = 0; j < dim; j++) {
                  v[j] = (float) mY[n - 1][j];
              }
              return;
          }
  
          for (int i = 0; i < n - 1; i++) {
              if (t == mT[i]) {
                  for (int j = 0; j < dim; j++) {
                      v[j] = (float) mY[i][j];
                  }
              }
              if (t < mT[i + 1]) {
                  double h = mT[i + 1] - mT[i];
                  double x = (t - mT[i]) / h;
                  for (int j = 0; j < dim; j++) {
                      double y1 = mY[i][j];
                      double y2 = mY[i + 1][j];
  
                      v[j] = (float) (y1 * (1 - x) + y2 * x);
                  }
                  return;
              }
          }
      }
  
      public double getPos(double t, int j) {
          final int n = mT.length;
          if (t <= mT[0]) {
              return mY[0][j];
          }
          if (t >= mT[n - 1]) {
              return mY[n - 1][j];
          }
  
          for (int i = 0; i < n - 1; i++) {
              if (t == mT[i]) {
                  return mY[i][j];
              }
              if (t < mT[i + 1]) {
                  double h = mT[i + 1] - mT[i];
                  double x = (t - mT[i]) / h;
                  double y1 = mY[i][j];
                  double y2 = mY[i + 1][j];
                  return (y1 * (1 - x) + y2 * x);
  
              }
          }
          return 0; // should never reach here
      }
  
      public void getSlope(double t, double[] v) {
          final int n = mT.length;
          int dim = mY[0].length;
          if (t <= mT[0]) {
              t = mT[0];
          } else if (t >= mT[n - 1]) {
              t = mT[n - 1];
          }
  
          for (int i = 0; i < n - 1; i++) {
              if (t <= mT[i + 1]) {
                  double h = mT[i + 1] - mT[i];
                  double x = (t - mT[i]) / h;
                  for (int j = 0; j < dim; j++) {
                      double y1 = mY[i][j];
                      double y2 = mY[i + 1][j];
  
                      v[j] = (y2 - y1) / h;
                  }
                  break;
              }
          }
          return;
      }
  
      public double getSlope(double t, int j) {
          final int n = mT.length;
  
          if (t < mT[0]) {
              t = mT[0];
          } else if (t >= mT[n - 1]) {
              t = mT[n - 1];
          }
          for (int i = 0; i < n - 1; i++) {
              if (t <= mT[i + 1]) {
                  double h = mT[i + 1] - mT[i];
                  double x = (t - mT[i]) / h;
                  double y1 = mY[i][j];
                  double y2 = mY[i + 1][j];
                  return (y2 - y1) / h;
              }
          }
          return 0; // should never reach here
      }
  
      @Override
      double[] getTimePoints() {
          return mT;
      }
  
  }
  