Question

I am capturing mouse events inside of a shell with Composites by adding a Filter.

For now the events are positioned relative to the Composites, where they occure.
How can I retrieve MouseEvents absolute position?
(Absolute position is the position with 0,0 in the left uper corner of the display).

parentShell.getDisplay().addFilter(SWT.MouseDown, new Listener() {
        @Override
        public void handleEvent(Event event) {
            //do not know the absolute position here
        }
    });

Answer 1

You can use Control#toDisplay(int, int) to convert any relative coordinates to display relative absolute values.

public void handleEvent(Event event) {
    if (event.widget instanceof Control) {
        Point absolutePos = ((Control) event.widget).toDisplay(event.x, event.y);
        ...
    }
}

The above will work if the event you received is a mouse event, which it is in your example. You can also use Display#getCursorLocation() at any point to get absolute mouse location if you do not have a mouse event at hand.