This small project adds colored borders to all user windows on macOS Sonoma and later. This tool can be used to better identify the currently focused window. It does not use the accessibility API and should thus be faster than comparable tools.

Current status: Early development.

Compile the source code to a binary using make in the cloned repository or install the binary via brew:

brew tap FelixKratz/formulae
brew update
brew install borders

The binary can be started via borders and takes either no arguments or the arguments (TODO: make this configurable during runtime):

borders active_color=<color_hex> inactive_color=<color_hex> width=<float>

which determine the color of the currently focused window, the inactive window and the width of the border respectively. The color hex shall be given in the format: 0xAARRGGBB, where A is the alpha channel, R the red channel, G the green channel and B the blue channel.

For example, if you are using yabai, you could add:

borders active_color=0xffe1e3e4 inactive_color=0xff494d64 width=5.0 2>/dev/null 1>&2 &

to the very end of your yabairc.

If you want to run this as a separate service, you could also use:

brew services start borders