1. Problem
2. Approach
3. Solution

Problem

Although the XFCE desktop environment offers an easy way to enlarge its user interface via Settings -> Appearance -> Fonts -> Custom DPI setting, such changes do not apply to titlebar buttons (such as the minimize, maximize, and close buttons) whose size remains constant.

Approach

The only workaround is to modify the XFCE theme by enlarging the underlying images that form titlebar buttons. Thankfully, I found a way to automate this laborious process as follows.

Solution

1. Install ImageMagick:

   sudo apt-get install imagemagick
   

2. Start with a copy of an existing theme (“Numix” in this example):

   mkdir ~/.themes
   cp -rT /usr/share/themes/Numix ~/.themes/Numix-large
   

3. Enlarge images for titlebar buttons (to 48 pixels in this example):

   cd ~/.themes/Numix-large/xfwm4
   for image in {top,title,menu,stick,shade,hide,maximize,close}-*.*
   do mogrify -resize x48 "$image"
   done
   

4. Apply your newly created large theme by choosing it from the list:

   xfwm4-settings
   

That’s all, enjoy!