pambackground

Create a mask of the background in a PAM image

$ pambackground [path/to/image.pam] > [path/to/output.pam]

pambackground [options] imagefile
pambackground -c color -p position -d imagefile

-c
    Sets the background color for areas not covered by the image. Color can be specified as '#RRGGBB' hexadecimal format.

-p
    Specifies how the image should be positioned on the screen. Common values include 'center', 'tile', 'stretch', or precise pixel offsets like 'NNxNN', or percentage offsets like 'NN%xNN%'.

-d
    Disables dithering when rendering the image, potentially improving image quality by using more precise colors.


    The path to the image file to be used as a background. This file must be in a Netpbm (PPM, PGM, or PBM) format.

pambackground is a utility designed to set a background image on the Linux console using the framebuffer device (typically /dev/fb0). It's commonly employed during the boot process or by display managers (like GDM, SDDM) to provide a visual backdrop before the full graphical environment loads, or for text-mode login screens. The command takes an image file in the Netpbm format (PPM, PGM, or PBM) as input. It can position the image (center, tile, stretch), set a background color for areas not covered by the image, and disable dithering for better image quality. Its primary purpose is to enhance the visual experience on the text console, making transitions smoother or providing branding. It does not affect graphical desktop environments once loaded.

pambackground requires a Linux console with framebuffer support enabled and active, typically accessible via /dev/fb0.
It needs appropriate permissions (often root privileges) to write to the framebuffer device.
The input image file must be in one of the Netpbm formats (PPM, PGM, or PBM). Other image formats are not supported directly.
This command operates on the text console and has no effect on graphical desktop environments once they are fully loaded.

Only Netpbm image formats (PPM, PGM, PBM) are supported. Converting other common formats (like JPEG, PNG) to Netpbm is necessary before use.

Running pambackground typically requires root privileges or membership in a group with write access to /dev/fb0 to modify the framebuffer device.

This command is often invoked by display managers (e.g., GDM, SDDM) or by PAM modules during the system's boot process or user login, to set a temporary background on the console before a graphical session starts.

pambackground is part of the pam_misc package, which provides miscellaneous PAM-related utilities. Its development is closely tied to the need for visual enhancements during the authentication and boot processes on Linux systems utilizing framebuffer consoles. It emerged as a simple, effective way to customize the console appearance before or during the start of a graphical session, or for purely text-based systems. It serves as a visual bridge, providing a consistent look and feel even before the desktop environment is fully initialized.

pam(8), ppm(5), fbset(8), fbi(1)