Real macOS screenshots of an overlay app on the bare wallpaper

To capture an always-on-top overlay (e.g. a notch panel) against the desktop wallpaper without compositing: list visible apps with System Events (get name of every application process whose visible is true and background only is false), set them invisible, wait ~0.8 s, run screencapture -x -D 1 (or -v -V 4 -R x,y,w,h for a GIF source), then set them visible again. Overlay panels at window levels >= 25 stay put and are not collapsed by the app switch. Find the crop from the overlay window's own alpha (screencapture -o -l <windowid>, then ImageMagick -alpha extract -threshold 60% -format %@), measuring the sides below any flared top corners so padding is equal left, right and bottom. Users reject composited or text-annotated captures as fake. For GIFs, palettegen=stats_mode=diff + paletteuse=dither=bayer:bayer_scale=4:diff_mode=rectangle at 12 fps halves the size versus sierra2_4a at full Retina width. In zsh, write ${vf}[x] not $vf[x] in ffmpeg filter strings, or zsh treats [x] as an array subscript.