Small Devices Backend

A backend used for smaller devices with limited functionality. I.e. small screen, no keyboard, low memory, low processor etc.

Possible Targets

WinCE -- small screen, no keyboard
PalmOS -- small screen, no keyboard, low resources, low memory
SymbianOS -- small screen, no keyboard, low resources, low memory
PSP -- no keyboard
PS2 -- no keyboard
DC (?)
GP32 -- small screen, no keyboard, low resources, low memory

Structure

All above devices will subclass this backend and possibliy override system-specific methods, i.e.:

 SDL --> SmallDevices --> WinCE
                      --> PalmOS
                      --> PSP
                      --> SymbianOS

Small Devices backend should be based on SDL backend, but should have most functions as virtual, so functionality could be overriden. An example is PSP which has hardware scalers, and PS2 where Lavos wants to implement 3D virtual keyboard.

It should add another level of abstraction and should let lowest level functions like input and screen blitting to be overriden. For example, PalmOS and GP32 backends do not use SDL. That shouldn't be really hard, as most functionality is in place and current SDL backend performs blitting only from 2 functions.

It should be written with extensive use of #ifdefs, so if I, say, don't need a virtual keyboard or downscalers for platform Foo, I don't bloat my code.

Common Subsystems

Virtual keyboard
Splash screen (most of ports have it, so it could be unified)
Downscalers, used for <320x200 screens
Zoning, like used in WinCE and SymbianOS. Zoning means away of switching around between the main area, actions area and inventory area for devices lacking mouse or touchscreen. The position within each zone is stored when switching between them.
Variable upscaler for weird resolutions (only used for small resolutions, say <=640x480, obviously cannot rely on fast FPU)
No scalers, but that should be under #ifdef as PSP and PS2 have enough power
Low-res sound
It should hide unneeded options from GUI like MT-32, MIDI device, i.e. those which either don't make sense or too fat for small devices