- Single touch + drag: scrub the highlight point along the chart,
map dot follows in real-time
- Tap: pan map to that point (10px threshold for movement)
- Two-finger touch: range select — area between fingers highlighted,
on release zooms map to fit that route section
- touch-none CSS + preventDefault prevents page scrolling on chart
Spec updated with mobile touch interaction scenarios.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Three new interactions:
1. Route hover → chart: Invisible interactive polyline (weight 20,
opacity 0) detects mouse hover on the route, computes cumulative
distance, and highlights the corresponding position on the chart.
2. Chart click → map pan: Clicking the elevation chart pans the map
to center on that point along the route. Uses 5px threshold to
distinguish from drag.
3. Chart drag-select → map zoom: Dragging a range on the chart shows
a blue selection overlay, then zooms the map to fit the route
coordinates in that range. "Reset zoom" button appears to restore
the full route view.
State flow avoids feedback loops: external highlights (from map hover)
set the chart crosshair without re-emitting onHover back to the map.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
