Software for GUI implementation using LPC2478?
Is there any software that helps me to implement GUI in LPC2478 microcontroller?
Is embOS compatible with LPC2478?
However embOS is an RTOS not a GUI and while that may be helpful in presenting a GUI on a real-time application, it does not in itself provide a GUI. Segger do however have a GUI product - emWin - which can be used with or without an RTOS, and independent of embOS. The issue there perhaps is whether your particular display device is supported, although it is possible to develop your own or use the microcontroller to control the LCD directly.
Either way embOS and emWin are commercial products with good documentation and excellent vendor support - you would do just as well to ask your questions at firstname.lastname@example.org.
Note that if you use Keil MDK-ARM Professional, then Segger emWin is included royalty-free.