Hi I am basically using cortex m3 series of processors for our application. I am looking for some GUI library that can be used for HMI. Is there any GUI libraries available? I recently heard about Qt. Is it a library written in C? Can I be able to port it to keil or IAR or Eclipse or any IDE? Or can you guys provide some other GUI library suggestions? Thanks!
Using Qt in a microcontroller project is infeasible. It requires megabytes of RAM and ROM and a full-fledged OS. There is support for embedded systems but it is limited to Nokia phone OSes, embedded Linux and Windows CE. See storage requirements for embedded Linux for example (note that these aren't RAM requirements). Qt has been used successfully on ARM9, ARM11 and Cortex-A systems such as FriendlyARM boards, BeagleBoard etc. (note that many of these have OpenGL ES hardware acceleration, too). Extra convenient support for Raspberry Pi is upcoming. If you actually need Qt, consider an ARM CPU-based (as opposed to a MCU-based) system running Linux.
If you do need to run a GUI on a microcontroller, see the answer linked to by embedded.kyle for realistic alternatives.
Open-source Embedded GUI Library https://littlevgl.com
LittlevGL is a free and open-source graphics library providing everything you need to create embedded GUI with easy-to-use graphical elements, beautiful visual effects and low memory footprint.
Powerful building blocks buttons, charts, lists, sliders, images etc
Advanced graphics with animations, anti-aliasing, opacity, smooth scrolling
Various input devices touch pad, mouse, keyboard, encoder etc
Multi language support with UTF-8 encoding
Fully customizable graphical elements
Hardware independent to use with any microcontroller or display
Scalable to operate with little memory (80 kB Flash, 10 kB RAM)
OS, External memory and GPU supported but not required
Single frame buffer operation even with advanced graphical effects
Written in C for maximal compatibility (C++ compatible)
Simulator to start embedded GUI design on PC without embedded hardware
Tutorials, examples, themes for rapid GUI design
Documentation online and offline
Free and open-source under MIT licence
I would stick with Qt. It's actually a C++ library. Keep in mind you need an embedded OS (Linux/Windows CE). There are plug-ins available for Eclipse and Visual Studio. Possibly others.
There are also some non-free alternatives mentioned in a similar SO question:
Just take a look at http://www.microcontrollercentral.com/author.asp?section_id=1741&doc_id=253618.
Rich Quinnell mentions probably what you are looking for.