Analysis in docs/brouter-findings.md: how BRouter knows roads (.rd5
segments), routes and reaches low elevation gain (profile uphill/downhill
cost + kinematics), the three call surfaces, and an evaluation of two ideas
— fill GPS gaps along roads, and offline waypoint route planning. License is
MIT; the engine has no desktop-only deps, so it embeds on Android ART.
Stage 1 (embed + bridge, compiles into the apk; on-device route not yet run):
- vendored brouter-1.6.3-all.jar into the Android module (dexes cleanly) and
bundled the trekking/shortest profiles + lookups.dat as assets, copied to
files/brouter/profiles2 on launch
- MainActivity: a brouter_command.txt handler on the existing FileObserver
runs btools.router.RoutingEngine off the UI thread (recipe taken via javap
from ServerHandler) and returns the track as GPX
- Rust brouter_route command: same file bridge as GPS (request + command,
poll for the result), registered in the invoke handler
- frontend/js/router.js: BRouter.route(points, profile) -> GPX (parseRouteGPX)
- LICENSE-brouter (MIT notice) kept alongside the vendored engine
Segments (.rd5, ~13-23 MB per 5x5 tile) are delivered later (Stage 2, wired
download inside BalDav). IMPLEMENTATION_PLAN.md tracks the 5 stages.
