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MapPolypoint implementation

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ClemensFischer 2024-07-15 13:41:52 +02:00
parent e8d4e47a45
commit 4e6d0db24f
3 changed files with 31 additions and 148 deletions
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30
MapControl/Avalonia/MapPolypoint.Avalonia.cs
View file

@ -51,31 +51,39 @@ namespace MapControl
protected void UpdateData(IEnumerable<Location> locations, bool closed)
{
var pathFigure = new PathFigure();
var pathFigures = new PathFigures();
if (ParentMap != null && locations?.Count() >= 2)
if (ParentMap != null && locations != null)
{
var longitudeOffset = GetLongitudeOffset(Location ?? locations.First());
var longitudeOffset = GetLongitudeOffset(Location ?? locations.FirstOrDefault());
AddPolylinePoints(pathFigure, locations, longitudeOffset, closed);
AddPolylinePoints(pathFigures, locations, longitudeOffset, closed);
}
((PathGeometry)Data).Figures = new PathFigures { pathFigure };
((PathGeometry)Data).Figures = pathFigures;
InvalidateGeometry(); // ignores an empty PathGeometry.Figures collection
InvalidateGeometry();
}
private void AddPolylinePoints(PathFigure pathFigure, IEnumerable<Location> locations, double longitudeOffset, bool closed)
private void AddPolylinePoints(PathFigures pathFigures, IEnumerable<Location> locations, double longitudeOffset, bool closed)
{
var points = locations
.Select(location => LocationToView(location, longitudeOffset))
.Where(point => point.HasValue)
.Select(point => point.Value);
pathFigure.StartPoint = points.First();
pathFigure.Segments.Add(new PolyLineSegment(points.Skip(1)));
pathFigure.IsClosed = closed;
pathFigure.IsFilled = true;
if (points.Any())
{
var figure = new PathFigure
{
StartPoint = points.First(),
IsClosed = closed,
IsFilled = true
};
figure.Segments.Add(new PolyLineSegment(points.Skip(1)));
pathFigures.Add(figure);
}
}
}
}

13
MapControl/WPF/MapPolypoint.WPF.cs
View file

@ -60,9 +60,9 @@ namespace MapControl
{
using (var context = ((StreamGeometry)Data).Open())
{
if (ParentMap != null && locations?.Count() >= 2)
if (ParentMap != null && locations != null)
{
var longitudeOffset = GetLongitudeOffset(Location ?? locations.First());
var longitudeOffset = GetLongitudeOffset(Location ?? locations.FirstOrDefault());
AddPolylinePoints(context, locations, longitudeOffset, closed);
}
@ -77,7 +77,7 @@ namespace MapControl
{
var longitudeOffset = GetLongitudeOffset(Location);
foreach (var polygon in polygons.Where(p => p?.Count() >= 2))
foreach (var polygon in polygons)
{
AddPolylinePoints(context, polygon, longitudeOffset, true);
}
@ -92,8 +92,11 @@ namespace MapControl
.Where(point => point.HasValue)
.Select(point => point.Value);
context.BeginFigure(points.First(), true, closed);
context.PolyLineTo(points.Skip(1).ToList(), true, true);
if (points.Any())
{
context.BeginFigure(points.First(), true, closed);
context.PolyLineTo(points.Skip(1).ToList(), true, true);
}
}
}
}

136
MapControl/WinUI/MapPolypoint.WinUI.cs
View file

@ -2,7 +2,6 @@
// Copyright © 2024 Clemens Fischer
// Licensed under the Microsoft Public License (Ms-PL)
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
@ -62,9 +61,9 @@ namespace MapControl
var pathFigures = ((PathGeometry)Data).Figures;
pathFigures.Clear();
if (ParentMap != null && locations?.Count() >= 2)
if (ParentMap != null && locations != null)
{
var longitudeOffset = GetLongitudeOffset(Location ?? locations.First());
var longitudeOffset = GetLongitudeOffset(Location ?? locations.FirstOrDefault());
AddPolylinePoints(pathFigures, locations, longitudeOffset, closed);
}
@ -77,12 +76,12 @@ namespace MapControl
.Where(point => point.HasValue)
.Select(point => point.Value);
if (closed)
if (points.Any())
{
var figure = new PathFigure
{
StartPoint = points.First(),
IsClosed = true,
IsClosed = closed,
IsFilled = true
};
@ -96,133 +95,6 @@ namespace MapControl
figure.Segments.Add(polyline);
pathFigures.Add(figure);
}
else
{
PathFigure figure = null;
PolyLineSegment polyline = null;
var viewport = new Rect(0, 0, ParentMap.RenderSize.Width, ParentMap.RenderSize.Height);
var pointList = points.ToList();
for (int i = 1; i < pointList.Count; i++)
{
var p1 = pointList[i - 1];
var p2 = pointList[i];
var inside = GetIntersections(ref p1, ref p2, viewport);
if (inside)
{
if (figure == null)
{
figure = new PathFigure
{
StartPoint = p1,
IsClosed = false,
IsFilled = true
};
polyline = new PolyLineSegment();
figure.Segments.Add(polyline);
pathFigures.Add(figure);
}
polyline.Points.Add(p2);
}
if (!inside || p2 != pointList[i])
{
figure = null;
}
}
}
}
/// <summary>
/// Calculates the potential intersections of a line segment given by (p1,p2) with a rectangle.
/// Updates either p1, p2, or both with any found intersection and returns a value that indicates
/// whether the segment intersects or lies inside the rectangle.
/// </summary>
private static bool GetIntersections(ref Point p1, ref Point p2, Rect rect)
{
if (rect.Contains(p1) && rect.Contains(p2))
{
return true;
}
var topLeft = new Point(rect.X, rect.Y);
var topRight = new Point(rect.X + rect.Width, rect.Y);
var bottomLeft = new Point(rect.X, rect.Y + rect.Height);
var bottomRight = new Point(rect.X + rect.Width, rect.Y + rect.Height);
var numIntersections = 0;
if (GetIntersection(ref p1, ref p2, topLeft, bottomLeft, p => p.X <= rect.X)) // left edge
{
numIntersections++;
}
if (GetIntersection(ref p1, ref p2, topLeft, topRight, p => p.Y <= rect.Y)) // top edge
{
numIntersections++;
}
if (numIntersections < 2 &&
GetIntersection(ref p1, ref p2, topRight, bottomRight, p => p.X >= rect.X + rect.Width)) // right edge
{
numIntersections++;
}
if (numIntersections < 2 &&
GetIntersection(ref p1, ref p2, bottomLeft, bottomRight, p => p.Y >= rect.Y + rect.Height)) // bottom edge
{
numIntersections++;
}
return numIntersections > 0;
}
private static bool GetIntersection(ref Point p1, ref Point p2, Point p3, Point p4, Predicate<Point> predicate)
{
var intersection = GetIntersection(p1, p2, p3, p4);
if (!intersection.HasValue)
{
return false;
}
if (predicate(p1))
{
p1 = intersection.Value;
}
else
{
p2 = intersection.Value;
}
return true;
}
/// <summary>
/// Returns the intersection point of two line segments given by (p1,p2) and (p3,p4),
/// or null if no intersection exists. See https://stackoverflow.com/a/1968345.
/// </summary>
private static Point? GetIntersection(Point p1, Point p2, Point p3, Point p4)
{
var x12 = p2.X - p1.X;
var y12 = p2.Y - p1.Y;
var x34 = p4.X - p3.X;
var y34 = p4.Y - p3.Y;
var x13 = p3.X - p1.X;
var y13 = p3.Y - p1.Y;
var d = x12 * y34 - x34 * y12;
var s = (x13 * y12 - y13 * x12) / d;
var t = (x13 * y34 - y13 * x34) / d;
if (s >= 0d && s <= 1d && t >= 0d && t <= 1d)
{
return new Point(p1.X + t * x12, p1.Y + t * y12);
}
return null;
}
}
}