#gradient

Slope and grade maths as an API, computed locally and deterministically. The convert endpoint converts a slope between every common form — percent grade, angle in degrees, a ratio such as 1:12, per mille and rise-per-run — where the slope m = rise ÷ run = tan(angle). The distance endpoint relates the run (horizontal), the rise (vertical) and the slope distance (the hypotenuse) of a right-triangle slope: give any two, optionally with the grade or angle, and it returns the rest. The ramp endpoint sizes a wheelchair or ADA ramp — from a rise and a maximum slope (defaulting to 1:12, the ADA maximum of 8.33%) it returns the required run and total ramp length, and if you supply an actual run it checks whether the ramp is within the limit. Everything is computed locally and deterministically, so it is instant and private. Ideal for civil-engineering and surveying tools, road, trail and accessibility apps, construction and ramp design, and mapping software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is slope and grade geometry; for roof pitch specifically use a roofing API.

api.oanor.com/slope-api

Generate colour gradients and colour scales programmatically. Produce an evenly-spaced scale of N colours between two or more stops (interpolated in a perceptually smooth colour space — lab, lch, oklab, oklch — or plain rgb/hsl), get a single interpolated colour at any position between two colours, and build a ready-to-paste CSS gradient string (linear with any angle, or radial) from a list of stops. Colours accept hex (#f00, #ff0000) or CSS names (red, steelblue). Perfect for data-visualisation colour ramps, heatmaps, chart palettes, theme generation and UI backgrounds. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 4 endpoints. Distinct from colour conversion / harmonious palettes (one base colour) and image palette extraction.

api.oanor.com/gradient-api