map_object.go

// Copyright 2016, 2017 Florian Pigorsch. All rights reserved.
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package sm

import (
	"github.com/fogleman/gg"
	"github.com/golang/geo/s2"
)

// MapObject is the interface for all objects on the map
type MapObject interface {
	// Bounds returns the geographical boundary rect (excluding the actual pixel dimensions).
	Bounds() s2.Rect

	// ExtraMarginPixels returns the left, top, right, bottom pixel margin of the object.
	ExtraMarginPixels() (float64, float64, float64, float64)

	// Draw draws the object in the given graphical context.
	Draw(dc *gg.Context, trans *Transformer)
}

// CanDisplay checks if pos is generally displayable (i.e. its latitude is in [-85,85])
func CanDisplay(pos s2.LatLng) bool {
	const minLatitude float64 = -85.0
	const maxLatitude float64 = 85.0
	return (minLatitude <= pos.Lat.Degrees()) && (pos.Lat.Degrees() <= maxLatitude)
}