Implement drivers for microwindows

[Acfboy]

Hello the community! Here is the work I have done in the early stage of GSoC.

Work Completed So Far

The GDI‑level Microwindows core, drivers, and mwdemo are functional on QEMU x86‑64 and the simulator.

Build System Integration

• Based on the initial proof-of-concept branch by @ppisa , the Microwindows core (engine, drivers, precompiled bitmap fonts) has been successfully compiled into the NuttX apps library.
• Resolved a build conflict: the ERROR macro in wingdi.h clashes with NuttX’s enum { ERROR = -1 }. The fix was to compile with -DNOGDI, a solution accepted by ghaerr and implemented upstream.
• Image resources used by mwdemo.c are compiled into binary using the convbmp tool during the build.

NuttX Hardware Drivers

Framebuffer driver (scr_nuttx.c), Keyboard driver (kbd_nuttx.c), Mouse driver (mou_nuttx.c), have been implemented to connect Microwindows to NuttX’s input/output subsystems.

Demo Application

Ported mwdemo.c (a complex Windows‑like demo) into a standalone NuttX example application. The demo runs successfully on both qemu‑intel64:mw and the NuttX simulator (sim:mw).

I have also tested the demo with #define CONTROL 1 enabled in mwdemo.c, which represents a more complex use case.

Upstream Bug Fixes

Several issues were discovered, analysed, and fixed – most of them already merged upstream:

Issue	Root Cause	Fix
Animation freezing in mwdemo	MwSelect() blocked forever when a timer had already expired, because the code assumed no timer existed when GdGetNextTimeout returned false.	Patch by ppisa (committed by ghaerr in PR #191): correctly handle the case where timeout == 0 and return immediately.
Cursor leaving a blue ghost image	#if defined(ELKS) in mwtypes.h forced MWPIXELVALHW to unsigned char even when ELKS=0 (intended to disable it). This truncated 32‑bit pixel values read from the framebuffer.	Changed to #if ELKS in ghaerr/microwindows@7a2ff57.
System freeze when dragging a window caption	During drag, MwSelect switches to polling (select(…, timeout=0)). The USB input thread had a lower priority (50) than the application (100), so it never got CPU time to generate events.	Short‑term: adjust thread priorities or add a minimal poll timeout. A permanent solution (refactoring the drag event loop) is under discussion. A NUTTX-specific patch will be prepared.

Remaining Issues

However, despite resolving several issues, two discovered problems are still under investigation. Due to a brief interruption while preparing for final exams, I have not yet fully diagnosed them. I will resume work soon and address the following:

1. When #define CONTROL 1 is enabled in mwdemo and input is tested in an edit box, backspace handling does not work correctly under QEMU.
2. In the simulator (sim), after dragging a window, the mouse cursor jumps outside the screen and drags the window off-screen as well.

Both issues appear to be related to the input drivers of the respective platforms. For instance, adding sample.point[0].x = x; sample.point[0].y = y; before the code at sim_touchscreen.c#L198-L220 resolves the mouse drift problem. It seems that sample.point[0] was previously uninitialized; however, the code branch in question never sets TOUCH_POS_VALID, so that value should not have been read in the first place. The root cause may lie elsewhere.

How to Reproduce (QEMU / Simulator)

qemu-intel64:mw

1. Download defconfig
2. Build nuttx

make distclean 
./tools/configure.sh qemu-intel64:mw
make -j$(nproc)

3. Creating a bootable disk following the instructions in the documentation
4. Run QEMU

qemu-system-x86_64 -cpu host -enable-kvm -m 2G \
        -cdrom boot_mw.iso \
         -serial stdio -monitor none -no-reboot -device qemu-xhci -device usb-kbd -device usb-mouse

sim:mw

1. Download defconfig
2. Build nuttx and run

make distclean 
./tools/configure.sh sim:mw
make -j$(nproc)
./nuttx

Notice

You can set #define CONTROL 1 manually in mwdemo.c to test more complex case.

Plan for the Second Half of GSoC

• Extend testing – verify on real hardware if possible; currently the work has been limited to QEMU and sim.
• Nano‑X (X11 API) port – enable Unix domain socket communication between the Nano‑X server and clients. The goal is to run multi‑client demos (e.g., src/demos/nanox/ applications).
• Driver submission to Microwindows mainline – after review by ghaerr, the NuttX screen/mouse/keyboard drivers should be integrated into the official Microwindows repository.
• Pull request to NuttX apps – submit a polished draft PR with all the work done so far, incorporating mentor feedback.
• Try to port FLTK gui framework and real-world applications.

[ppisa]

Thanks to @Acfboy for the work and this draft request for discussion and @ghaerr for consultations and support on Microwidows side.

I am leaving for four days now, but there are some my thoughts, the NuttX Microwidows screen, mouse and keyboard drivers should be submitted with appropriate build enable options to the mainline Microwindows https://github.com/ghaerr/microwindows before the final nuttx-apps pull request.

[acassis]

@Acfboy hello -> microwindows

[acassis]

@Acfboy please fix the issues on mwdemo: