Interface to select floor

[jannis-baum]

An overlay to select from a list of available floors is displayed for each building with visible indoor data.

Context

• loading map with specific floor selected & default selection: see Generate & display geoJSON according to floors as given by database #135
• indoor data may be hidden: see Display indoor map data by level of magnification #137

Acceptance

- [ ] overlay is displayed at appropriate position and visually clearly belonging to building

• clicking a floor on the list switches displayed indoor data to that floor and visually selects the floor on the list
• overlay always has currently displayed floor selected (also if map is opened to display non-default floor at load)
• there is an API to allow for one of the list-items to be highlighted in red color on load. this will be used by the navigation to signal the target room being on that floor.

updated issue

Floating overlays as given by mockups seem to be too complicated to implement for the value they give. As a proposed alternative, Leaflet's layer selector will be used as follows

Acceptance

• floors are loaded as an independent set of layers for each building
• interface to select a floor's layer has heading stating the related building's name and (if visible) is always expanded
• interfaces to select a floor's layer (as seen in picture) are visible as follows
  • if indoor map is hidden (according to zoom level, see Display indoor map data by level of magnification #137 ): no floor selection interface is visible
  • if no buildings are within the map's view: no floor selection interface is visible
  • if indoor map is visible and there is at least one building within the map's view: only the center-most building's floor selection interface is visible
• see original acceptance