Xwindow Interface

The Xwindow interface on EusLisp becomes available when EusLisp is invoked by the name of 'eusx'. ³The "DISPLAY" environment variable should be properly set to your Xserver, since eusx tries to connect to Xserver referencing the "DISPLAY" environment variable when it starts up.

EusLisp defines three levels of xwindow interface: (1) Xlib functions, (2) Xlib classes, and (3) XToolKit classes. All the xwindow functions described in this section and the following XToolKit section are contained in the "X" package. The function names of the original Xlib are changed so that all constituent letters are converted to upcase and the first 'X' prefix is removed. For example, XdefaultGC is named X:DEFAULTGC, not X:XDEFAULTGC.

The Xlib functions are defined as foreign functions as the lowest level interface to Xwindow system. These Xlib functions should be used carefully, since parameter type check or parameter number check is not performed. For an instance, all the Xlib call requests x:*display* argument to identify the connection to Xserver, and if you forget it, Xlib reports an error and the process dies. The second level interface, Xlib classes are provided to avoid this inconvenience and to make the interface object-oriented. This section focuses on this second level interface. Even higher level xwindow library called XToolKit is explained in the next section.

Classes described in this section have the following inheritance hierarchy.

propertied-object
   viewsurface
      x:xobject
         x:gcontext
         x:xdrawable
             x:xpixmap
             x:xwindow
   colormap