Programmatically set very high VirtualBox guest resolution - virtualbox

Question

I would like my VM to have a ton of screen space. I'm fine with having to scroll to see the entire desktop, but I want a desktop in the VM much larger than the size of my current monitor. For example, if I have 1920x1080 monitor, I want to have a 2560x1600 desktop.
I know it's technically possible, because sometimes from strange resizing and what-not, I end up getting a VirtualBox window that is smaller than the guest OS's resolution, and scroll bars appear.

Answer 1

Having a similar need, I've searched and found the following: http://flink.formula9.net/?p=229
I've successfully performed the following using a OS X 10.10.3 host and Windows 8.1 guest (adapted to example by Andersson):
close the VirtualBox Manager
in the shell, run:
VBoxManage setextradata global GUI/MaxGuestResolution any
start the guest
in the shell, run:
VBoxManage controlvm "Windows 8 VM" setvideomodehint 3200 1800 32

Answer 2

Using Windows as host and VM target I have managed to achieve this the following way:
Close VirtualBox if open.
Open a command prompt and cd to the virtualbox installation dir
Run: VBoxManage.exe setextradata "NAME OF VM" CustomVideoMode1 WxHxD
Where "NAME OF VM" is the name of the virtual machine, W is width, H is height, D is depth.
e.g. To make 2560x1600 available for my VM with the name "Windows 8 VM" i would:
..VirtualBox> VBoxManage.exe setextradata "Windows 8 VM" CustomVideoMode1 2560x1600x32
The next time I boot up the "Windows 8 VM" I'm able to see the new custom resolution in the list together with the default resolutions (i.e. right click on desktop->Screen resolution).
Not sure if this method works on other hosts/targets than Windows.

Answer 3

Just use "Scale Factor", VirtualBox"6.1.32" Max “Scale Factor” could up to "300%".
You know,
"Guest Resolution" * "Scale Factor" == "Host Display size".
Or
"Max Guest Screen size" * "Scale Factor" >= "Host Display size".
e.g:
"1024*640" * "250%" == "2560*1600";
"1280*800" * "200%" == "2560*1600";
"2560*1600" * "100%" == "2560*1600";
Just use your default "1920×1080 monitor" for an example:
"1920×1080" * "100%" == "1920×1080" < "2560*1600`";
"1920×1080" * "200%" == "3840×2160" > "2560*1600";
"1920×1080" * "250%" == "4800×2700" > "2560*1600";
"1920×1080" * "300%" == "5760×3240" > "2560*1600";
Now, change your VM "Scale Factor", VM "Max Guest Screen Size",
Guest-General Display "Scale Factor" and Guest-Settings Display
"Resolution".
Notices:
Guest-Settings Display "Resolution" should be the same as VM "Max Guest Screen Size".
VM "Scale Factor" should be the same as Guest-General Display "Scale Factor".
Just use Virtual box for an example:
e.g: "1280*800" * "200%" == "2560*1600";
1.VM scale factor and max screen size:
click VirtualBox APP, then you see "Oracle Vm VirtualBox Manager",
move your mouse to top menu, found out VirtualBoxlogo, select
"Preference", then enter "VirtualBox – General", click Display,
Choose "Maximum screen size" to "Hint" with Width "1280" and
Height "800", and adjust "Scale Factor" to "200%", then click
"OK".
Guest scale factor:
When you enter VirtualBox APP, then you see "Oracle Vm VirtualBox Manager",
found out your guest machine name button, as mine is "linux_debian_11",
you will see "Power Off" under the name of your guest machine.
Please found out your guest machine "Menu Box Button", that is at the right
of your guest machine name, right-click your "Menu Box" or single click your
"Guest Machine Box", choose "Settings", then you will enter your guest
machine's "General", mine is "linux_debian_11 – General", then click
"Display", and adjust "Scale Factor" to "200%"(the same as Scale Factor
On virtual machine's "General").
Guest Resolution:
My guest machine is "Debian". So, just use "Debian" for an example here.
Click my guest machine "Debian"'s “Settings”, then found out "Display",
and, also, choose "Resolution" to "1280*800(16:10)".
No matter your Debian version is "8", or even "11", the upstairs settings
Is OK.
Are you ok? Said, Lei Jun.
Reboot Host Machine:
Now, it's your time to show!
Please restart my Mac/Windows.