+/** @param align_standard Standard with which to interpret this subtitle's position.
+ * @param align alignment.
+ * @param position position (between 0 and 1)
+ * @param target_height Height of the target screen (in pixels).
+ * @param baseline_to_bottom Distance from text baseline to the bottom of the bounding box (in pixels).
+ * @param layout_height Height of the subtitle bounding box (in pixels).
+ * @return y position of the top of the subtitle bounding box (in pixels) from the top of the screen.
+ */