Uniform round nib, centered smoothing on committed strokes, causal filtering for the live
preview, and a tiled layer that re-rasterizes vectors at every zoom level. The live stroke
raises its layer resolution while you draw zoomed in. Pen, pencil, and highlighter each
keep their own opacity and blend behavior. The vector eraser’s hit radius stays constant
on screen as you zoom.
Input
Pencil draws, fingers pan
Scroll is restricted to finger touches so a Pencil cannot pan the page. Two-finger tap undoes; three-finger tap redoes. Scribble over ink to erase it — gated so handwriting is never mistaken for a delete.
Shapes
Hold to snap
Strokes score against line, arrow, rectangle, ellipse, triangle, and diamond. Hold about a second and the best fit wins; lift normally and the ink stays exactly as drawn.
Scanning
Real paths, not a photo
Orientation, threshold, and printed-ruling removal are derived from the page. Thin marks get centrelines; filled marks get outlines. Both become ordinary ink strokes — erasable, undoable, exportable as SVG.
Paper
Blank, ruled, graph, Cornell
Plus draggable shapes, stickers, text boxes, and graph cards, with a persistent sticker library for diagrams you reuse across notebooks.
