Touch Coordinates

How Board contact positions map into the web SDK’s coordinate space.

Origin and axes

Contacts arrive in screen pixels with the origin at the top-left, x increasing to the right, and y increasing downward. This matches the browser’s standard screen convention, so no flip is needed when you draw to a canvas or position DOM elements.

Orientation

Piece orientation is reported in degrees, normalized to [0, 360), and is only meaningful for Piece (Glyph) contacts. The convention: (cos θ, sin θ) is a unit vector pointing where the physical Piece is facing, in the same Y-down screen space as x/y — so 0 faces right (+X) and a clockwise physical turn increases the angle. Draw orientation indicators straight from it; no per-game correction is needed.

Resolution

The Board panel is 1920x1080. Contacts are reported in that device-pixel space.