discuss.visual-prolog.com

Posted: **5 Mar 2014 14:04**

Hi,

I am very new to visual prolog and want to find out how I can get the X,Y coordinates of
a point from the contextMenuInput.

I am using this in the OnContextMenu event. onContextMenu(_Source, _INP) = window::defaultContextMenuHandling

contextMenuInput =
mouse(vpiDomains::pnt CursorPosition);
keyboard.

I see the point and its X,Y coordinates in the debugger, but I don't know how to extract these from the _INP variable.

Posted: **6 Mar 2014 13:09**

You extract/project the sub-values by matching a term containing variables against the value.

Code: Select all

window::mouse(vpiDomains::pnt(X, Y)) = Inp

Here in context:

Code: Select all

predicates
    onContextMenu : contextMenuResponder.
clauses
    onContextMenu(_Source, Inp) = window::defaultContextMenuHandling :-
        if window::mouse(vpiDomains::pnt(X, Y)) = Inp then
            stdio::writef("Context menu mouse press at X = %, Y = %\n", X, Y)
        else
            stdio::writef("Context menu invoked by keyboard")
        end if.

Posted: **6 Mar 2014 13:40**

Thank you. That worked perfectly.

discuss.visual-prolog.com

Retrieve pnt from contextMenuInput

Retrieve pnt from contextMenuInput