Drum Lane

The rhythm sibling of the piano roll: named lanes (Kick, Snare, Hat…) down the left, a beat grid across, and every hit drawn at its exact onset so timing and swing are legible — a round marker that visibly sits off the gridline when a hit is pushed or swung, over a sixteenth grid that stays countable while it plays. Velocity is the marker's size and opacity, accents wear a ring, and sustained hits grow a tail. It shares the piano roll's whole beat axis, host-driven playhead, active-hit highlight and --uikit-* theming through the same geometry core (createLaneLayout), changing only what a drum view needs: taller rows, text labels instead of a keyboard, and hits placed by lane instead of pitch. The playhead is a prop the host drives; null draws no cursor and no readout, so a stopped transport shows nothing pinned at zero.