Add possibility for dotted line for walking route

[imaginaris]

Mapbox Navigation SDK version: 0.35.0

It would be really nice to have dotted line for walking route. Setting lineDashPattern and lineCap does not help much as the dots are being stretched and bended when zoom level changes (I guess it's because this property does not support interpolation).

[1ec5]

Unfortunately, this is a design decision on the part of the Mapbox GL project. You can read the rationale here: https://github.com/mapbox/mapbox-gl-js/issues/2351#issuecomment-202586487 https://github.com/mapbox/mapbox-gl-js/issues/3427#issuecomment-262354870.

Consider setting MGLLineStyleLayer.linePattern to an image that contains a circle with some padding or returning an MGLSymbolStyleLayer whose symbolPlacement is line and whose iconImageName looks like a circle.

[andrlee]

@designevokes heads up! ^

[1ec5]

Although a dotted line isn’t part of the style specification, the navigation SDK should use a dashed line to represent any walking segment of a route based on the RouteStep.transportType property. This would pair nicely with the camera and puck improvements tracked in #1942.