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Increase DPI

Posted: 22. Feb 2021, 17:10
by balcerman
Hello,

How can I increase my screen resolution?
I know how to increase the screen itself with guest additions, but I also need something else - I specifically mean increasing the DPI, so everything is smaller and there are more pixels on the screen.

My current configuration:

Code: Select all

Windows version: 7 (host)

Linux version (guest):
$ cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)

Kernel version:
$ uname --kernel-release
3.10.0-1127.19.1.el7.x86_64


$ plasma-desktop --version
Qt: 4.8.5
KDE Development Platform: 4.14.8
Plasma Desktop Shell: 4.11.19

$ gnome-shell --version
GNOME Shell 3.14.4

Xserver version:
$ rpm -qa |grep xorg-x11-server-Xorg
xorg-x11-server-Xorg-1.17.2-10.el7.x86_64

Oracle VM VirtualBox version:
6.1.18 r142142 (Qt5.6.2)

Guest Additions version:
$ ls /opt | grep GuestAdditions
VBoxGuestAdditions-6.1.18
$ lsmod | grep -io vboxguest | xargs modinfo | grep -iw version
version:        6.1.18 r142142

Re: Increase DPI

Posted: 22. Feb 2021, 17:44
by scottgus1
Virtualbox doesn't have anything to make the VM render dpi smaller or bigger. That is covered by the OS installed in the VM. Web-search your VM OS's controls for changing DPI, font size, etc.

The actual number of pixels will not change, that's dependent on the physical and virtual monitor(s).

Re: Increase DPI

Posted: 23. Feb 2021, 09:40
by balcerman
Hello scottgus1,

Isn't it that graphics controller combo has impact on the maximum resolution?

EDIT: it seems to me that the VirtualBox has some influence on the resolution settings - I can easily change the resolution on CentOS but all I get is the increase or decrease of the VirtualBox screen instead of VM screen matching my monitor size. When I set the resolution to big enough numbers, I don't get the "smaller objects on the screen" effect but the VM screen exceeds the monitor size, making part of it not visible. I'd like to keep VM screen size matching my monitor, no matter what resolution I choose.

Re: Increase DPI

Posted: 23. Feb 2021, 11:48
by mpack
balcerman wrote: Isn't it that graphics controller combo has impact on the maximum resolution?
No. Your physical monitor determines resolution.

Re: Increase DPI

Posted: 23. Feb 2021, 17:56
by scottgus1
balcerman wrote:I'd like to keep VM screen size matching my monitor, no matter what resolution I choose.
The only setup that I know of that does this is Scaled. On an XP VM I first set the VM to Full-screen so it could register 16:9 resolutions from my monitor. Then I set the VM to Scaled Mode and maximized the VM window to lock the window to my monitor size. After that, I could set screen sizes larger than the monitor size and the VM scaled appropriately. Note that scaling a VM whose resolution is larger than the host's physical monitor resolution will be fuzzy. The VM window's title bar is also always displayed.