The R Project SVN R

    /********************************************************				 

     * Event handling entries

     ********************************************************/

    /* These determine whether getGraphicsEvent will try to set an event handler */

    Rboolean canGenMouseDown; /* can the device generate mousedown events */

    Rboolean canGenMouseMove; /* can the device generate mousemove events */

    Rboolean canGenMouseUp;   /* can the device generate mouseup events */

    Rboolean canGenKeybd;     /* can the device generate keyboard events */

    Rboolean gettingEvent;    /* This is set while getGraphicsEvent is actively looking for events */

    SEXP eventRho;	      /* This is the environment of getGraphicsEvent in which to evaluate the handlers */

    SEXP eventResult;	      /* The result of the last event handler is stored here, unprotected */

    /* These are the event handlers */

    SEXP mouseDownHandler;

    SEXP mouseMoveHandler;

    SEXP mouseUpHandler;

    SEXP keybdHandler;

    /*

     * device_getEvent is called by do_getGraphicsEvent to get a modal

     * graphics event.  It should call R_ProcessEvents() until one

     * of the event handlers sets eventResult to a non-null value,

     * and then return it

     * An example is ...

     *

     * static SEXP GA_getEvent(char *prompt);

     */

    SEXP (*getEvent)();