I use the coordinate system conversion functions i.e. to convert OSD viewport coordinates to image pixel coords. Indeed it needed some thinking to get through the different system (especially when handling conversion from viewport-pixels to image-pixels) but after I got that it was well understandable :) OSD is initialized on a div which hast an offset due to preceeding divs with content. Now I try to get the mousevent coorinates and try to translate it into image pixel coordinates. Is it possible that https://openseadragon.github.io/docs/OpenSeadragon.Viewport.html#windowToImageCoordinates
is not aware of that offset? Maybe I'm on the wrong way for this, but at the moment I do some offset calculation taking the document-offset of the topleft image point in relation to the OSD div... (geee... the more I try to explain the more I lose the understanding of what I'm doing :) ).