i'm on Ubuntu 18.04 with Virtualbox 5.2.32. I want to run an old windows game in a xp guest, the game needs to be run with a resolution of 640x480 and 16-bit hicolor. When i disable auto-resize guest display in "view" and then in view / virtual monitor 1 / 740x480 the xp guest is running only with the resolution i need and it isn't changed when i resize the vbox window. without disabled auto-resize the resolution is changed every time i resize the vbox window. using scale factor i can resize the window without changed the resolution. But there are 2 problems:
every time i start the vm i have to change the color depth to 16 bit. can i change this in virtualbox so that windows xp "thinks" it can only run with 16 bit?
i can only use the given scale factors. i want to use vbox in fullscreen and scale the display to the maximum that is possible. at the moment there is a lot of grey around the xp display and scale factor 200 is the maximum i can choose
Performance will be horrible, unless you also run the host with 16-bit hicolor, because your proposal would require every guest pixel to be up-converted in software before being painted on the host display - that's assuming that it works at all (I'm pretty sure it will not work with accelerated graphics).
Struggle on with this if you like, but my hopes are not high.
It works. The Problem is that i have to change the settings manually every time i Start the vm. The goal is that XP runs with this settings every time and i dont need to change anything.
VirtualBox presents a set of capabilities, but it is for the guest OS to request the graphics mode it wants to use. There's no way I know of in VirtualBox to hide capabilities: it's going to suggest whatever is optimal for the current host.
Normally whatever mode XP shuts down in, that's the mode it selects on startup next time. Are you actually shutting down XP, not suspending? In fact I'd try it both ways (shut down and suspend/restore).