Ubuntu – How to make PDFs appear life-size when displayed at 100%


When I open a letter size PDF and then zoom to 100%, the page physically displayed on my monitor is smaller than a real letter size sheet of paper.

How can I make "100%" on the computer screen correspond with "100%" in real life?


This message suggests that I should be investigating the system-wide DPI settings for my monitor. xdpyinfo reports:

dimensions:    1024x768 pixels (271x203 millimeters)
resolution:    96x96 dots per inch

My monitor has a native display resolution of 1024×768 pixels and a diagonal display size of 12.07 inches. PX CALC returns the following information:

DPI: 106.05
Dot Pitch: 0.2395mm
Size: 9.66" × 7.24" (24.53cm × 18.39cm)

What I've tried so far

Running xrandr --dpi 106.05 successfully caused my PDF to appear actual size at 100%, but this effect was lost after rebooting.

To make the setting persistent I tried creating the following /etc/X11/xorg.conf:

Section "Monitor"
    Identifier   "ThinkPad X60 LCD"
    DisplaySize  245 183

Section "Screen"
    Identifier "Screen0"
    Monitor    "ThinkPad X60 LCD"

After re-logging in, /var/log/Xorg.0.log contained

[  1167.824] (**) intel(0): Display dimensions: (245, 183) mm
[  1167.824] (**) intel(0): DPI set to (106, 106)

but xdpyinfo still reported

dimensions:    1024x768 pixels (271x203 millimeters)
resolution:    96x96 dots per inch

and "100%" still appeared too small.

Best Answer

  • xorg.conf doesn't even exist on new installs nowadays because of xrandr. Most drivers work fine with just xrandr and no xorg.conf (I think Nvidia is the exception). What you need is to have xrandr run at startup all the time. I documented on the Ubuntu Wiki how to make xrandr commands run as soon as the GUI starts. Just use the same xrandr command you already figured out.

    For Unity users reading along, equivalent directions for lightdm are here: https://askubuntu.com/a/69501/1158