Issues when switching GraphicsV drivers

When switching the current GraphicsV driver via OS_ScreenMode 11 a few things get messed up:

1. The current pointer palette isn’t passed across
2. The pointer state isn’t passed over
3. The desktop mode changes
4. Fonts change (eg Edit Command window font)

Switching away from the stock Pi driver and then back to it for example will result in a low res 256 colour desktop, with no pointer and a partially redrawn screen. Pressing F12 then ENTER will however restore the desktop.

There are ways to fix some of these issues, such as:

1. OS_Byte 106 1 before and after switching driver
2. “Wimp_ForceRedraw” -1, 0, 0, 65536, 65536 after switching drivers
3. OS_ScreenMode 0 before switching and OS_ScreenMode 1 after

I’m not sure how to programmatically fix the fonts though, but ideally all this should be done by OS_ScreenMode 11.

Admittedly this isn’t something that’s likely to be an issue for anyone, as the driver is in the ROM. It may however become an issue if legacy mode support is added in the future, if it’s done via a separate GraphicsV driver.

Should you want to repro some of this issues, load ADFFS 2.70 and then quit it from the Filer, or RMKill ADFFS from a task window.