EZwgl (10.4 Write Your Own Display Items)

## 10.4 Write Your Own Display Items

EZwgl also provides a way for you to write your own display items and make it available to `EZ_CreateItemXrm`. To do so, you need to

- {provide the following 8 procedures

        setup(EZ_Item *item);
        computeSize(EZ_Item *item, int *w, int *h);
        draw(EZ_Widget *widget, Drawable  drawable, int x0, int y0,
             EZ_Item   *item, int Rx, int Ry, int Rw, int Rh);
        update(EZ_Widget *widget, Drawable  drawable,
               EZ_Item   *item, int Rx, int Ry, int Rw, int Rh);
        highlight(EZ_Widget  *widget, Drawable drawable,
                  EZ_Item  *item, unsigned long fg, unsigned long bg,
                  int Rx, int Ry, int Rw, int Rh, int flag);
        freePrivateData(EZ_Item *item);
        int pick(EZ_Item *item, int x, int y);
        postscript (EZ_Item *item, FILE *fp, void *psinfo);

  }

- {call `EZ_RegisterItem` to register your item. This function returns an integer type identifier which can be passed to `EZ_CreateItem` to instantiate the registered item.}

- {write interface routines as needed.}

---details to come---

HTML Documentation Maintainance:`Arturo Espinosa <arturo@nuclecu.unam.mx>`