public void Update()
{
double oldMercatorToViewScale = _mercatorToViewScale;
Vector oldTranslation = _translation;
_mercatorToViewScale = 256 * Math.Pow(2, ZoomLevel) / MercatorLocation.Width;
var offset = new Vector
{
X = Width / _mercatorToViewScale / 2,
Y = -Height / _mercatorToViewScale / 2
};
_translation = new Vector
{
X = -Position.X + offset.X,
Y = -Position.Y + offset.Y
};
_viewToMercatorScale = 1 / _mercatorToViewScale;
_visibleMercatorRectangle = ToScene(VisibleViewRectangle);
if (oldMercatorToViewScale != _mercatorToViewScale ||
oldTranslation != _translation)
{
EmitChanged();
}
}
public Rect ToView(MercatorRectangle rect)
{
Point topLeft = ToView(new MercatorLocation(rect.Min.X, rect.Max.Y));
Point bottomRight = ToView(new MercatorLocation(rect.Max.X, rect.Min.Y));
double x = Math.Min(topLeft.X, bottomRight.X);
double y = Math.Min(topLeft.Y, bottomRight.Y);
double width = Math.Max(topLeft.X, bottomRight.X) - x;
double height = Math.Max(topLeft.Y, bottomRight.Y) - y;
return(new Rect
{
X = x,
Y = y,
Width = width,
Height = height
});
}
/// <summary>
/// </summary>
/// <param name="rectangle"></param>
/// <param name="zoomLevel"></param>
/// <returns></returns>
public static TileRectangle CreateFrom(MercatorRectangle rectangle, int zoomLevel)
{
var zoomFactor = Math.Pow(x: 2, y: zoomLevel);
var tileEdgeLength = MercatorRectangle.Earth.Width / zoomFactor;
// Given zoom level = 1
// (X: 0, Y: 0) is top left
// (X: 1, Y: 0) is top right
// (X: 1, Y: 1) is bottom right
// => We can interpolate
var xDifference = rectangle.Min.X - MercatorRectangle.Earth.Min.X;
var yDifference = rectangle.Min.Y - MercatorRectangle.Earth.Min.Y;
var x = (int)(xDifference / tileEdgeLength);
var y = (int)(yDifference / tileEdgeLength);
var width = (int)Math.Ceiling(rectangle.Width / tileEdgeLength);
var height = (int)Math.Ceiling(rectangle.Height / tileEdgeLength);
return(new TileRectangle(x, y, zoomLevel, width, height));
}