// returns the zoom level for supplied bounds
// useful when rendering static map images
// pass in 0.0 for maxzoom for no maxzoom
//
// TODO: add padding support
func BoundsZoom(proj crs.ProjectTransformer, bounds geo.LatLngBounds, size geometry.Point, maxZoom float64) float64 {
zoom := 0.0
nw := bounds.NorthWest()
se := bounds.SouthEast()
zoomNotFound := true
for {
zoom++
boundsSize := crs.LatLngToPoint(proj, se, zoom).Subtract(crs.LatLngToPoint(proj, nw, zoom)).Floor()
zoomNotFound = size.Contains(boundsSize)
if zoomNotFound && zoom <= maxZoom {
continue
} else {
break
}
}
// if a maxZoom was set and zoom is greater than maxZoom, return maxZoom
if maxZoom != 0.0 && zoom > maxZoom {
return maxZoom
}
// return the calculated zoom
return zoom
return zoom - 1.0
}
func CenterBoundsZoom(proj crs.ProjectTransformer, bounds geo.LatLngBounds, size geometry.Point, maxZoom float64) (geo.LatLng, float64) {
// calculate our zoom
zoom := BoundsZoom(proj, bounds, size, maxZoom)
// convert to points
swPoint := crs.LatLngToPoint(proj, bounds.SouthWest(), zoom)
nePoint := crs.LatLngToPoint(proj, bounds.NorthEast(), zoom)
// find center
center := crs.PointToLatLng(proj, swPoint.Add(nePoint).DivideBy(2), zoom)
return center, zoom
}