Expand description
Simple pipe: a_input == 255, BlendMode::Normal, no soft mask, no shape.
Equivalent to Splash::pipeRunSimple{Mono8,RGB8,XBGR8,BGR8,CMYK8,DeviceN8}.
Mono1 is excluded: 1-bit packed bitmaps require bit-level addressing that
belongs in the fill/stroke caller, not a generic span function.