private void AddAffectedAreaLayer(Map map, Polygon affectedArea)
{
var geoms = new List <IGeometry>()
{
affectedArea
};
if (!map.MapTransform.IsIdentity)
{
// affectedArea is aligned with Graphics Canvas (not with north arrow)
// The following steps are simply to show this geom in world units
var centreX = affectedArea.EnvelopeInternal.Centre.X;
var centreY = affectedArea.EnvelopeInternal.Centre.Y;
// apply negative rotation about center of polygon
var rad = NetTopologySuite.Utilities.Degrees.ToRadians(map.MapTransformRotation);
var trans = new AffineTransformation();
trans.Compose(AffineTransformation.TranslationInstance(-centreX, -centreY));
trans.Compose(AffineTransformation.RotationInstance(-rad));
var rotated = trans.Transform(affectedArea.Copy());
// calculate enclosing envelope
var minX = rotated.Coordinates.Min(c => c.X);
var minY = rotated.Coordinates.Min(c => c.Y);
var maxX = rotated.Coordinates.Max(c => c.X);
var maxY = rotated.Coordinates.Max(c => c.Y);
var coords = new Coordinate[]
{
new Coordinate(minX, maxY),
new Coordinate(maxX, maxY),
new Coordinate(maxX, minY),
new Coordinate(minX, minY),
new Coordinate(minX, maxY),
};
// rotate enclosing envelope back to world units
trans = new AffineTransformation();
trans.Compose(AffineTransformation.RotationInstance(rad));
trans.Compose(AffineTransformation.TranslationInstance(centreX, centreY));
// construct geom to show on screen
var enclosing = trans.Transform(new Polygon(new LinearRing(coords)));
geoms.Add(enclosing);
}
var gp = new GeometryProvider(geoms);
var vLayer = new VectorLayer("Affected Area")
{
DataSource = gp,
SRID = map.SRID
};
vLayer.Style.Fill = null;
vLayer.Style.EnableOutline = true;
//vLayer.Enabled = false;
map.Layers.Add(vLayer);
}
/// <summary>
/// Affine transformation defining complete transformation from world coordinate system (WCS) to image coordinates taking into
/// account Zoom, Pixel Width/Height, and MapTransformRotation. Additionally, if <paramref name="careAboutTransform"/> = false,
/// the viewport rotation will be reverted at the end of the transformation, to be re-applied by Graphics object when rendering.
/// </summary>
/// <param name="worldCenter">Map center in WCS</param>
/// <param name="pixelWidth">Width of pixel in world units</param>
/// <param name="pixelHeight">Height of pixel in world units</param>
/// <param name="mapTransformRotation">map rotation in degrees</param>
/// <param name="imageSize">Map Size when rendered</param>
/// <param name="careAboutTransform">True for coordinate calculations, False if Graphics object will apply MapTransform</param>
/// <returns>Affine Transformation</returns>
public static AffineTransformation WorldToMapMatrix(Coordinate worldCenter,
double pixelWidth, double pixelHeight, float mapTransformRotation, Size imageSize,
bool careAboutTransform)
{
var rad = NetTopologySuite.Utilities.Degrees.ToRadians(mapTransformRotation);
var trans = new AffineTransformation();
trans.Compose(AffineTransformation.TranslationInstance(-worldCenter.X, -worldCenter.Y));
trans.Compose(AffineTransformation.RotationInstance(-rad));
trans.Compose(AffineTransformation.ScaleInstance(1 / pixelWidth, -1 / pixelHeight));
trans.Compose(AffineTransformation.TranslationInstance(imageSize.Width * 0.5, imageSize.Height * 0.5));
if (!careAboutTransform)
{
// if we DON'T care about transform (implies that rotation in image space WILL be performed by graphics
// object once drawing of ALL objects has been completed) then need to revert rotation (ie MapTransform).
trans.Compose(AffineTransformation.RotationInstance(-rad, imageSize.Width * 0.5, imageSize.Height * 0.5));
}
return(trans);
}
