/// <summary>
/// Convert a position on the device's display to the corresponding geo-coordinate.
/// </summary>
/// <param name="screenPosition">Screen position to convert.</param>
/// <returns>Geo-coordinate which represents the screen position.</returns>
public GeoCoordinate ConvertScreenPositionToGeoCoordinate(Vector2 screenPosition)
{
// Get vector from the screen center to the screen position, but on the entire map image
Vector2 fromScreenCenterToPositionNonScaled = (screenPosition - screenCenterVector) / zoomScale;
Vector2 screenPositionPixelXY = ScreenCenterPixelXY + fromScreenCenterToPositionNonScaled;
return(TileSystem.PixelXYToLatLong(screenPositionPixelXY, ZoomLevel));
}
/// <summary>
/// Initializes the active tile plane by requesting images centered at the specified geo-coordinate.
/// </summary>
/// <param name="centerCoordinate">The geo-coordinate which will serve as the center of the
/// middle tile.</param>
private void GetActivePlaneImages(GeoCoordinate centerCoordinate)
{
Vector2 centerPixelXY = TileSystem.LatLongToPixelXY(centerCoordinate, zoomLevel);
int planeCenterIndex = PlaneCenterIndex;
for (int xIndex = 0; xIndex < ActiveTilePlaneSize; xIndex++)
{
int xDelta = xIndex - planeCenterIndex;
for (int yIndex = 0; yIndex < ActiveTilePlaneSize; yIndex++)
{
int yDelta = yIndex - planeCenterIndex;
TileInformation cellInformation = activeTilePlane[xIndex, yIndex];
// Initialize or clean the active tile cube cell
if (cellInformation == null)
{
cellInformation = new TileInformation(TileServerRequestCompleted);
activeTilePlane[xIndex, yIndex] = cellInformation;
}
else
{
cellInformation.Dispose();
}
// Calculate the center geo-coordinate for the current tile
Vector2 tileCenterPixelXY = centerPixelXY + tileDimensions * new Vector2(xDelta, yDelta);
GeoCoordinate tileCenterGeoCoordinate;
try
{
tileCenterGeoCoordinate = TileSystem.PixelXYToLatLong(tileCenterPixelXY, zoomLevel);
GetImageFromServer(cellInformation, tileCenterGeoCoordinate, zoomLevel, ViewType);
}
catch (ArgumentOutOfRangeException)
{
cellInformation.Image = unavailableImage;
}
}
}
}