ClemensFischer/XAML-Map-Control
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Removed LatLonBox

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The rotation behavior of a KML LatLonBox has no sufficiently precise specification.
This commit is contained in:
ClemensFischer 2026-01-27 20:12:57 +01:00
parent 6c89dfcdae
commit a0e82964ef
10 changed files with 75 additions and 144 deletions
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98
MapControl/Shared/MapProjection.cs
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@ -138,71 +138,69 @@ namespace MapControl
public Location MapToLocation(Point point) => MapToLocation(point.X, point.Y);
/// <summary>
/// Transforms a BoundingBox in geographic coordinates to a Rect in projected map coordinates.
/// Returns null when the BoundingBox can not be transformed.
/// Transforms a BoundingBox in geographic coordinates to a Rect in projected map coordinates
/// with an optional transform Matrix when the BoundingBox is not projected axis-aligned.
/// Returns (null, null) when the BoundingBox can not be transformed.
/// </summary>
public Rect? BoundingBoxToMap(BoundingBox boundingBox)
public (Rect?, Matrix?) BoundingBoxToMap(BoundingBox boundingBox)
{
Rect? rect = null;
Matrix? transform = null;
var sw = LocationToMap(boundingBox.South, boundingBox.West);
var ne = LocationToMap(boundingBox.North, boundingBox.East);
return sw.HasValue && ne.HasValue ? new Rect(sw.Value, ne.Value) : null;
if (sw.HasValue && ne.HasValue)
{
if (boundingBox.ProjectAxisAligned)
{
rect = new Rect(sw.Value, ne.Value);
}
else
{
var se = LocationToMap(boundingBox.South, boundingBox.East);
var nw = LocationToMap(boundingBox.North, boundingBox.West);
if (se.HasValue && nw.HasValue)
{
var south = new Point((sw.Value.X + se.Value.X) / 2d, (sw.Value.Y + se.Value.Y) / 2d); // south midpoint
var north = new Point((nw.Value.X + ne.Value.X) / 2d, (nw.Value.Y + ne.Value.Y) / 2d); // north midpoint
var west = new Point((nw.Value.X + sw.Value.X) / 2d, (nw.Value.Y + sw.Value.Y) / 2d); // west midpoint
var east = new Point((ne.Value.X + se.Value.X) / 2d, (ne.Value.Y + se.Value.Y) / 2d); // east midpoint
var center = new Point((west.X + east.X) / 2d, (west.Y + east.Y) / 2d); // midpoint of segment west-east
var dx1 = east.X - west.X;
var dy1 = east.Y - west.Y;
var dx2 = north.X - south.X;
var dy2 = north.Y - south.Y;
var width = Math.Sqrt(dx1 * dx1 + dy1 * dy1); // distance west-east
var height = Math.Sqrt(dx2 * dx2 + dy2 * dy2); // distance south-north
rect = new Rect(center.X - width / 2d, center.Y - height / 2d, width, height);
if (dy1 != 0d || dx2 != 0d)
{
// Skew matrix with skewX = Atan(-dx2 / dy2) and skewY = Atan(-dy1 / dx1).
//
transform = new Matrix(1d, -dy1 / dx1, -dx2 / dy2, 1d, 0d, 0d);
}
}
}
}
return (rect, transform);
}
/// <summary>
/// Transforms a Rect in projected map coordinates to a BoundingBox in geographic coordinates.
/// Returns null when the Rect can not be transformed.
/// </summary>
public BoundingBox MapToBoundingBox(Rect rect)
public BoundingBox MapToBoundingBox(Rect rect, bool axisAligned = false)
{
var sw = MapToLocation(rect.X, rect.Y);
var ne = MapToLocation(rect.X + rect.Width, rect.Y + rect.Height);
return sw != null && ne != null ? new BoundingBox(sw, ne) : null;
}
/// <summary>
/// Transforms a LatLonBox in geographic coordinates to a rotated Rect in projected map coordinates.
/// Returns (null, null) when the LatLonBox can not be transformed.
/// </summary>
public (Rect?, Matrix?) LatLonBoxToMap(LatLonBox latLonBox)
{
Rect? rect = null;
Matrix? transform = null;
var sw = LocationToMap(latLonBox.South, latLonBox.West);
var se = LocationToMap(latLonBox.South, latLonBox.East);
var nw = LocationToMap(latLonBox.North, latLonBox.West);
var ne = LocationToMap(latLonBox.North, latLonBox.East);
if (sw.HasValue && se.HasValue && nw.HasValue && ne.HasValue)
{
var south = new Point((sw.Value.X + se.Value.X) / 2d, (sw.Value.Y + se.Value.Y) / 2d); // south midpoint
var north = new Point((nw.Value.X + ne.Value.X) / 2d, (nw.Value.Y + ne.Value.Y) / 2d); // north midpoint
var west = new Point((nw.Value.X + sw.Value.X) / 2d, (nw.Value.Y + sw.Value.Y) / 2d); // west midpoint
var east = new Point((ne.Value.X + se.Value.X) / 2d, (ne.Value.Y + se.Value.Y) / 2d); // east midpoint
var center = new Point((west.X + east.X) / 2d, (west.Y + east.Y) / 2d); // midpoint of segment west-east
var dx1 = east.X - west.X;
var dy1 = east.Y - west.Y;
var dx2 = north.X - south.X;
var dy2 = north.Y - south.Y;
var width = Math.Sqrt(dx1 * dx1 + dy1 * dy1); // distance west-east
var height = Math.Sqrt(dx2 * dx2 + dy2 * dy2); // distance south-north
var x = center.X - width / 2d;
var y = center.Y - height / 2d;
rect = new Rect(x, y, width, height);
if (dy1 != 0d || dx2 != 0d || latLonBox.Rotation != 0d)
{
// Skew matrix with skewX = Atan(-dx2 / dy2) and skewY = Atan(-dy1 / dx1).
//
var t = new Matrix(1d, -dy1 / dx1, -dx2 / dy2, 1d, 0d, 0d);
t.Rotate(-latLonBox.Rotation);
transform = t;
}
}
return (rect, transform);
return sw != null && ne != null
? new BoundingBox(sw.Latitude, sw.Longitude, ne.Latitude, ne.Longitude, axisAligned)
: null;
}
public override string ToString()