57.5 Arrows and Cartesian Axes🔗ℹ

An arrow Visual stores one ordered shaft from a start point to an end point. The untransformed midpoint is its reference position. Optional triangular tips can be attached independently to the start and end. Tip dimensions are local world-unit geometry. Stroke width is cosmetic output style.

An axis range stores a minimum, maximum, and regular positive tick step. The range must contain zero because the built-in Cartesian axes cross at numeric coordinate (0, 0). Tick values are ordered nonzero multiples of the step that lie in the closed range.

An axes Visual maps the complete numeric x and y ranges to explicit local x and y lengths. It contains two shafts, regular ticks, and optional tips at the maximum x and y endpoints. Numeric coordinates can be converted to points in the axes’ containing coordinate system and converted back again. The conversion includes the axes’ translation, rotation, and positive scale.

Arrows and axes are pure semantic values. Their model modules do not contain Picts, drawing paths, drawing contexts, pixels, or text labels. The built-in adapter derives ordinary path geometry when rendering them.