getPixelFromCoordinateInternal(coordinate) {
    const frameState = this.frameState_;
    if (!frameState) {
      return null;
    }
    return applyTransform(
      frameState.coordinateToPixelTransform,
      coordinate.slice(0, 2),
    );
  }
Get the pixel for a coordinate.  This takes a coordinate in the map view
projection and returns the corresponding pixel.
@param {import("./coordinate.js").Coordinate} coordinate A map coordinate.
@return {import("./pixel.js").Pixel} A pixel position in the map viewport.