private void DrawCylindricalGraticule(DrawingContext drawingContext, MapProjection projection, double lineDistance, string labelFormat)
{
var boundingBox = projection.ViewportRectToBoundingBox(new Rect(ParentMap.RenderSize));
if (boundingBox.HasValidBounds)
{
var latLabelStart = Math.Ceiling(boundingBox.South / lineDistance) * lineDistance;
var lonLabelStart = Math.Ceiling(boundingBox.West / lineDistance) * lineDistance;
var latLabels = new List <Label>((int)((boundingBox.North - latLabelStart) / lineDistance) + 1);
var lonLabels = new List <Label>((int)((boundingBox.East - lonLabelStart) / lineDistance) + 1);
var typeface = new Typeface(FontFamily, FontStyle, FontWeight, FontStretch);
var pixelsPerDpi = VisualTreeHelper.GetDpi(this).PixelsPerDip;
var pen = CreatePen();
for (var lat = latLabelStart; lat <= boundingBox.North; lat += lineDistance)
{
latLabels.Add(new Label(lat, new FormattedText(
GetLabelText(lat, labelFormat, "NS"),
CultureInfo.InvariantCulture, FlowDirection.LeftToRight, typeface, FontSize, Foreground, pixelsPerDpi)));
drawingContext.DrawLine(pen,
projection.LocationToViewportPoint(new Location(lat, boundingBox.West)),
projection.LocationToViewportPoint(new Location(lat, boundingBox.East)));
}
for (var lon = lonLabelStart; lon <= boundingBox.East; lon += lineDistance)
{
lonLabels.Add(new Label(lon, new FormattedText(
GetLabelText(Location.NormalizeLongitude(lon), labelFormat, "EW"),
CultureInfo.InvariantCulture, FlowDirection.LeftToRight, typeface, FontSize, Foreground, pixelsPerDpi)));
drawingContext.DrawLine(pen,
projection.LocationToViewportPoint(new Location(boundingBox.South, lon)),
projection.LocationToViewportPoint(new Location(boundingBox.North, lon)));
}
foreach (var latLabel in latLabels)
{
foreach (var lonLabel in lonLabels)
{
var position = projection.LocationToViewportPoint(new Location(latLabel.Position, lonLabel.Position));
drawingContext.PushTransform(new RotateTransform(ParentMap.Heading, position.X, position.Y));
drawingContext.DrawText(latLabel.Text,
new Point(position.X + StrokeThickness / 2d + 2d, position.Y - StrokeThickness / 2d - latLabel.Text.Height));
drawingContext.DrawText(lonLabel.Text,
new Point(position.X + StrokeThickness / 2d + 2d, position.Y + StrokeThickness / 2d));
drawingContext.Pop();
}
}
}
}
/// <summary>
/// Transforms a Location in geographic coordinates to a Point in viewport coordinates.
/// </summary>
public Point LocationToViewportPoint(Location location)
{
return(MapProjection.LocationToViewportPoint(location));
}
