decode_box.dart

Array decodeBox(
      List<double> rawBoxes, int i, List<Anchor> anchors, OptionsFace options) {
    Array boxData = Array(List<double>.generate(options.numCoords, (i) => 0.0));
    int boxOffset = i * options.numCoords + options.boxCoordOffset;
    double yCenter = rawBoxes[boxOffset];
    double xCenter = rawBoxes[boxOffset + 1];
    double h = rawBoxes[boxOffset + 2];
    double w = rawBoxes[boxOffset + 3];
    if (options.reverseOutputOrder) {
      xCenter = rawBoxes[boxOffset];
      yCenter = rawBoxes[boxOffset + 1];
      w = rawBoxes[boxOffset + 2];
      h = rawBoxes[boxOffset + 3];
    }

    xCenter = xCenter / options.xScale * anchors[i].w + anchors[i].xCenter;
    yCenter = yCenter / options.yScale * anchors[i].h + anchors[i].yCenter;

    if (options.applyExponentialOnBoxSize) {
      h = exp(h / options.hScale) * anchors[i].h;
      w = exp(w / options.wScale) * anchors[i].w;
    } else {
      h = h / options.hScale * anchors[i].h;
      w = w / options.wScale * anchors[i].w;
    }

    double yMin = yCenter - h / 2.0;
    double xMin = xCenter - w / 2.0;
    double yMax = yCenter + h / 2.0;
    double xMax = xCenter + w / 2.0;

    boxData[0] = yMin;
    boxData[1] = xMin;
    boxData[2] = yMax;
    boxData[3] = xMax;

    if (options.numKeypoints > 0) {
      for (int k = 0; k < options.numKeypoints; k++) {
        int offset = i * options.numCoords +
            options.keypointCoordOffset +
            k * options.numValuesPerKeypoint;
        double keyPointY = rawBoxes[offset];
        double keyPointX = rawBoxes[offset + 1];

        if (options.reverseOutputOrder) {
          keyPointX = rawBoxes[offset];
          keyPointY = rawBoxes[offset + 1];
        }
        boxData[4 + k * options.numValuesPerKeypoint] =
            keyPointX / options.xScale * anchors[i].w + anchors[i].xCenter;

        boxData[4 + k * options.numValuesPerKeypoint + 1] =
            keyPointY / options.yScale * anchors[i].h + anchors[i].yCenter;
      }
    }
    return boxData;
  }