A texture redrawn column by column into a target, one layer of a {:layers, [layer]} change: a warp given as a table.

• target — :frame (the default) or a canvas handle
• clear — {r, g, b, a} from 0 to 1 the target is filled with first, or nil
• port — {x, y, width, height} in the target's pixels, the part redrawn; nil is the whole target
• source — the handle of the texture or canvas read
• columns — one {u, v_scale, shade} per column of the port, left to right

Each column of the port reads the source at the horizontal position u (0 its left edge, 1 its right). A pixel down of the way from the port's top (0 to 1) reads the vertical position 0.5 + (down − 0.5) × v_scale. The source is sampled between its four nearest pixels, edges repeated, and its colour multiplied by shade. A position outside 0 to 1 draws opaque black. When the port has more pixels across than there are columns, the columns are stretched to fill it.