PtInitDrag

Arguments

Returns

nil on success.

Example

This example, ex_PtInitDrag.g, is included in the product distribution.

#!/usr/cogent/bin/phgamma

/*
This example puts a small window on the screen with a text label that
can be dragged.
*/

require_lisp("PhotonWidgets");

PtInit(nil);

win = new(PtWindow);
win.SetDim(200,200);
PtRealizeWidget(win);

lab = new(PtLabel);
lab.text_string = "Drag Me";
PtRealizeWidget(lab);

DraggedWidget := nil;

method PtWidget.StartDrag ()
{
   DraggedWidget = self;
   PtInitDrag (self, nil, Ph_TRACK_DRAG | Ph_DRAG_TRACK);
}

function handle_drag ()
{
   local   event = cbinfo.event, rect;

   if (event.type == Ph_EV_DRAG)
   {
      if (event.subtype == Ph_EV_DRAG_COMPLETE ||
            event.subtype == Ph_EV_DRAG_MOVE)
      {
         if (DraggedWidget)
         {
            rect = TranslateRect (event_data.drag_event.rect,
              event.translation);
            DraggedWidget.SetPos (rect.ul.x, rect.ul.y);
         }
         if (event.subtype == Ph_EV_DRAG_COMPLETE)
            DraggedWidget = nil;
      }
   }
}

PtAttachCallback(win,Pt_CB_RAW,#handle_drag(),Ph_EV_DRAG);
PtAttachCallback(lab,Pt_CB_RAW,#widget.StartDrag(),Ph_EV_BUT_PRESS);

PtMainLoop();

See Also

In Photon documentation: PhInitDrag.