bool VideoFrameTransform::transformPlane()

in Transform360/Library/VideoFrameTransform.cpp [742:833]
80 lines of code
15 McCabe index (conditional complexity)

bool VideoFrameTransform::transformPlane(
  const Mat& inputMat,
  Mat& outputMat,
  int outputWidth,
  int outputHeight,
  int transformMatPlaneIndex,
  int imagePlaneIndex) {
  // For Barrel layout we want to have some black spots on the video frame,
  // so we need to change border mode to transparent, to avoid overwriting them.
  int borderMode =
      (ctx_.output_layout == LAYOUT_BARREL ||
       ctx_.output_layout == LAYOUT_BARREL_SPLIT) ?
      BORDER_TRANSPARENT :
      BORDER_WRAP;
  try {
    switch (ctx_.interpolation_alg) {
      case NEAREST:
      case LINEAR:
      case CUBIC:
      case LANCZOS4:
        {
          Mat tempMat;
          if (ctx_.enable_low_pass_filter) {
            // Filter frame plane with filters
            tempMat = filterPlane(
              inputMat,
              transformMatPlaneIndex,
              imagePlaneIndex);
          } else {
            tempMat = inputMat;
          }

          bool needResize =
            (outputHeight != warpMats_[transformMatPlaneIndex].rows ||
            outputWidth != warpMats_[transformMatPlaneIndex].cols);

          if (!needResize) {
            // We want to set default YUV values to 0.
            // UV (plane index > 0) planes are scaled from [-1, 1],
            // so we set it to 128.
            if (transformMatPlaneIndex &&
              (ctx_.output_layout == LAYOUT_BARREL ||
              ctx_.output_layout == LAYOUT_BARREL_SPLIT)) {
              outputMat.setTo(Scalar(128));
            }
            remap(
              tempMat,
              outputMat,
              warpMats_[transformMatPlaneIndex],
              cv::Mat(),
              ctx_.interpolation_alg,
              borderMode);
          } else {
            // We want to set default YUV values to 0.
            // UV (plane index > 0) planes are scaled from [-1, 1],
            // so we set it to 128.
            Mat scaledWarpedImage(
              warpMats_[transformMatPlaneIndex].size(),
              tempMat.type(),
              Scalar(transformMatPlaneIndex ? 128 : 0));
            remap(
              tempMat,
              scaledWarpedImage,
              warpMats_[transformMatPlaneIndex],
              cv::Mat(),
              ctx_.interpolation_alg,
              borderMode);
            resize(
              scaledWarpedImage,
              outputMat,
              Size(outputWidth, outputHeight),
              0,
              0,
              INTER_AREA);
          }
          break;
        }
      default:
        printf(
          "Could not find interpolation algorithm for plane %d",
          imagePlaneIndex);
    }
  } catch (const exception& ex) {
    printf(
      "Could not transform the plane %d. Error: %s\n",
      imagePlaneIndex,
      ex.what());
      return false;
  }

  return true;
}