nickvasilescu/nicks-stack/desktop-wallpapers

Desktop Wallpapers

Use this skill when the user asks for a cool desktop background, VM wallpaper, lock-screen-style image, or wants a generated image applied as a desktop wallpaper.

Workflow

1. Determine the target surface and platform.

• If the user says "your computer", inspect the live environment before assuming a desktop environment.
• On Linux, check XDG_CURRENT_DESKTOP, DISPLAY, WAYLAND_DISPLAY, and available wallpaper tools.
• For XFCE, xfconf-query is the most direct way to set the background.

1. Prefer real image generation when available.

• Use the configured image generation tool for the requested style and aspect ratio.
• For desktop backgrounds, default to landscape / 16:9 unless the user specifies otherwise.
• Avoid text/logos/watermarks unless explicitly requested (model-compare fleets often request company logo + model name — honor that).
• Leave negative space if the desktop has icons.

1. If image generation is unavailable because credentials/billing/provider setup is missing, do not stop at the error.

• Capture the setup fix briefly if useful, but continue with a local fallback when possible.
• A good fallback is a deterministic procedural PNG/SVG wallpaper generated with Python stdlib or existing graphics tools.
• Verify the generated image dimensions and file validity before applying it.

1. Save the artifact in a sensible user-visible location.

• Linux VM default: ~/Pictures/<descriptive-name>.png.
• Use an absolute path in the final reply.

1. Apply the wallpaper using the desktop environment's native mechanism.

• XFCE: set xfce4-desktop backdrop properties with xfconf-query, then reload xfdesktop if present.
• GNOME: use gsettings set org.gnome.desktop.background picture-uri file:///absolute/path.
• KDE Plasma, Windows, and macOS require platform-specific commands; inspect first rather than guessing.

1. Verify.

• Confirm the image exists and has expected dimensions.
• Confirm the desktop configuration points to the generated file when the platform exposes a query command.
• On Orgo/Xvnc: also confirm nonblack and color-diverse paint via screenshot (see Orgo section). xfconf alone is not enough.

XFCE wallpaper commands

For an XFCE VM with VNC/virtual monitors, update all matching backdrop paths rather than only one monitor key:

IMG=/absolute/path/to/wallpaper.png
for prop in \
  /backdrop/screen0/monitor0/image-path \
  /backdrop/screen0/monitorVirtual-1/workspace0/image-path \
  /backdrop/screen0/monitorscreen/workspace0/image-path; do
  xfconf-query -c xfce4-desktop -p "$prop" -s "$IMG" 2>/dev/null || true
done
for prop in $(xfconf-query -c xfce4-desktop -l | grep -E '/last-image$'); do
  xfconf-query -c xfce4-desktop -p "$prop" -s "$IMG" 2>/dev/null || true
done
for prop in $(xfconf-query -c xfce4-desktop -l | grep -E '/image-style$'); do
  xfconf-query -c xfce4-desktop -p "$prop" -s 5 2>/dev/null || true
done
for prop in $(xfconf-query -c xfce4-desktop -l | grep -E '/image-show$'); do
  xfconf-query -c xfce4-desktop -p "$prop" -s true 2>/dev/null || true
done
# Prefer restart over --reload (reload can hang the shell 60s+)
if pgrep -x xfdesktop >/dev/null; then
  kill -HUP "$(pgrep -x xfdesktop | head -1)" 2>/dev/null || true
else
  # terminal(background=true) or Python Popen(start_new_session=True)
  DISPLAY="${DISPLAY:-:99}" xfdesktop &
fi
xfconf-query -c xfce4-desktop -l -v | grep -F "$IMG" || true

Orgo / Xvnc verification (co-located or remote fleet)

On Orgo desktops (DISPLAY=:99, VNC), wallpaper work is not done when xfconf points at a file. Paint can be dead while config looks correct.

1. Confirm xfdesktop is running (pgrep -a xfdesktop). Panel + xfwm4 alone can leave a black root — most common post-apply failure is xfdesktop dying while xfconf still lists the correct PNG.
2. Prefer orgo-desktop screenshot when co-located; on remote fleet boxes use Orgo bash + scrot / PIL.
3. Fail closed on black / solid-only paint:

• pure black PNG ≈ 2700–3500 bytes
• solid xsetroot color ≈ 14–20KB with high nonblack but low color diversity — wallpaper FAIL
• real wallpaper: often 100KB–1.2MB with hundreds of unique color samples

1. Recovery order (do not stop after soft restart if paint is still flat):

a. Soft: relaunch xfsettingsd / xfwm4 / xfce4-panel / xfdesktop (Python Popen(start_new_session=True)). b. Re-pin every image-path / last-image + image-style=5. c. If still flat: full Xvnc restart per orgo-desktop-local references/black-framebuffer-recovery.md, then re-pin and verify diversity.

1. After any Xvnc restart, tell the user to hard-refresh / reconnect noVNC.

Fleet multi-box apply, exact-filename waits, and recovery transcripts: references/orgo-xfce-wallpaper-apply.md.

Procedural fallback

When no image-generation backend is usable, create a procedural wallpaper instead of declaring the task impossible. A small Python script can write a valid PNG directly with zlib/struct, avoiding external dependencies like ImageMagick or Pillow.

See scripts/procedural_neon_wallpaper.py for a dependency-free 1920x1080 neon Linux command-center wallpaper generator.

Pitfalls

• Do not save a durable rule that a specific image provider is unavailable; provider credentials and billing are environment state.
• Do not use GUI computer-use for wallpaper changes when CLI desktop settings are available.
• Do not use shell-level background wrappers for launching GUI apps/processes; use tracked background process tools when needed. Launch xfdesktop / Xvnc with terminal(background=true) or Python start_new_session=True — Hermes rejects foreground nohup/&.
• xfdesktop --reload can hang the shell (60s+ timeout observed). Prefer kill -HUP on the existing PID, or pkill -x xfdesktop then relaunch; then verify with a screenshot.
• Some minimal VMs lack file, ImageMagick, Pillow, or desktop portals. Verify PNGs with Python by reading the PNG header when common utilities are missing.
• For XFCE, setting only one image-path may not affect the visible VNC/virtual monitor. Enumerate xfconf-query -c xfce4-desktop -l and update monitor/workspace keys (monitor0, monitorVNC-0 last-image per workspace, monitorVirtual-1, monitorscreen).
• AI image backends often emit ~1024×576 even for landscape. Fine when image-style is 5 (scaled) on 1280×720 VNC; not a failure. Second gen / upscale only if the user wants sharper fill.
• xfconf success ≠ visible wallpaper. Always verify nonblack and color-diverse paint after apply.
• User: "wallpapers disappeared / went black" is almost always dead/missing xfdesktop (or dead Xvnc paint), not deleted files. Check pgrep -x xfdesktop and screenshot diversity before re-generating images.
• Soft client relaunch can leave a solid root color that is nonblack but not the wallpaper. Require unique color samples, not just nonblack counts.
• Fleet multi-box uploads: wait for the exact filename on that computer; delete other wallpaper-*.png so apply scripts do not pick a sibling box's art.
• Nick prefers company-logo + model-name branding wallpapers for model-compare fleets when he asks for model-matched backgrounds (overrides generic "avoid logos" default).