Skip root pixmap access when alpha == 255

When alpha is 255 (fully opaque), the pseudo-transparency blend factor
is zero (0xFFFF - 257 * 255 = 0), making the root pixmap composite a
visual no-op. However, drawBackground unconditionally calls
XRenderCreatePicture on the _XROOTPMAP_ID pixmap.

Wallpaper setters like feh free the old root pixmap via XKillClient
each time they cycle to a new image. If xmobar attempts
XRenderCreatePicture on the freed pixmap, the X server returns
BadDrawable and the default error handler terminates xmobar.

Guard the entire root pixmap code path with `when (alpha < 255)` so
that fully opaque bars never touch _XROOTPMAP_ID.

0 files changed, 0 insertions, 0 deletions