Canvas
When Room is Custom, these sizes are used. Changing width or height here also switches Room to Custom (up to 4096 px per side).
Horizontal Bands
White boundary lines (only when Horizontal bands is on):
Grid
Same step on X and Y. Offsets shift where lines start (pixel phase).
Vertical splits
Equal-width columns: N segments → N − 1 lines. Offset moves every line by the same amount (pixels); the slider spans ±room width for the current canvas size.
Skip bands: split lines use the same top / middle / bottom heights as Horizontal bands. Checked = do not draw through that band.
Box
Safe-area guide: equal inset on all sides from the shorter canvas dimension (%), then the inner rectangle is cropped to match the chosen band aspect ratio (centered in the inset). Offset Y shifts the whole guide up (−) or down (+), clamped to ±room height. Until you edit this field, it stays auto so the box is vertically centered in the middle band (updates when room size, inset, aspect, or band heights change).
Frame
Solid border on the canvas edges. Width is clamped so the inner area stays at least 1×1 px.
Tileset
Arranges copies of the current room in a columns × rows atlas (left→right, top→bottom). Each cell keeps the room’s pixel size; the atlas is cols × width by rows × height. Output is capped at 4096 px per side.
When Cell numbers is on, draws 0, 1, 2… (row by row) in a 10px monospace font at the top-left of each tile.
Tile fill
Used when Tileset preview is on: how each atlas cell is filled (room color, random RGB, or 90s palette).
90s palette picks a random saturated retro color per tile from the same palette each time the preview redraws (large pool of shades; repeats are possible).