@mutantMecha The parallax offset is based on the distance between the origin (top-left) of the map and the center of the view. The origin was chosen because it never changes, whereas when using for example the center of the map it would change when resizing the map (and this would be especially weird for “infinite” maps). The center of the view was chosen because it was the most “viewport size” agnostic option.
However, I understand that this may not be ideal. We could introduce a “parallax origin” property, so that you don’t need to offset each layer. There is also a plan to add viewports, which can also come with additional options for parallax, like using a different reference point than the center.
In any case, if you’d like to go into more detail about what you need, please open an issue about it on GitHub or open a new topic here.