private List <Vector> ClipToBounds(Rectangle bounds)
{
var points = new List <Vector>();
var n = _edges.Count;
var i = 0;
while (i < n && _edges[i].visible == false)
{
i++;
}
if (i == n)
{
return(new List <Vector>());
}
var edge = _edges[i];
var orientation = _edgeOrientations[i];
points.Add(edge.clippedEnds[orientation]);
points.Add(edge.clippedEnds[LR.Other(orientation)]);
for (var j = i + 1; j < n; ++j)
{
//TODO: Watch out for preincrement!!!
edge = _edges[j];
if (edge.visible == false)
{
continue;
}
Connect(points, i, bounds);
}
Connect(points, i, bounds, true);
return(points);
}
private void Connect(List <Vector> points, int j, Rectangle bounds, bool closingUp = true)
{
var rightPoint = points[points.Count - 1];
var newEdge = _edges[j];
var newOrientation = _edgeOrientations[j];
var newPoint = newEdge.clippedEnds[newOrientation];
// The points do not coincide, so they must have been clipped at the bounds;
// see if they are on the same border of the bounds:
if (!CloseEnough(rightPoint, newPoint))
{
if (rightPoint.X != newPoint.X && rightPoint.Y != newPoint.Y)
{
// They are on different borders of the bounds;
// insert one or two corners of bounds as needed to hook them up:
// (NOTE this will not be correct if the region should take up more than
// half of the bounds rect, for then we will have gone the wrong way
// around the bounds and included the smaller part rather than the larger)
var rightCheck = BoundsCheck.Check(rightPoint, bounds);
var newCheck = BoundsCheck.Check(newPoint, bounds);
double px;
double py;
if (rightCheck & BoundsCheck.RIGHT)
{
px = bounds.right;
if (newCheck & BoundsCheck.BOTTOM)
{
py = bounds.bottom;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.TOP)
{
py = bounds.top;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.LEFT)
{
py = rightPoint.Y - bounds.Y + newPoint.Y - bounds.Y < bounds.Height ? bounds.top : bounds.bottom;
points.Add(new Vector(px, py));
points.Add(new Vector(bounds.left, py));
}
}
else if (rightCheck & BoundsCheck.LEFT)
{
px = bounds.left;
if (newCheck & BoundsCheck.BOTTOM)
{
py = bounds.bottom;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.TOP)
{
py = bounds.top;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.RIGHT)
{
py = rightPoint.Y - bounds.Y + newPoint.Y - bounds.Y < bounds.Height
? bounds.top
: bounds.bottom;
points.Add(new Vector(px, py));
points.Add(new Vector(bounds.right, py));
}
}
else if (rightCheck & BoundsCheck.TOP)
{
py = bounds.top;
if (newCheck & BoundsCheck.RIGHT)
{
px = bounds.right;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.LEFT)
{
px = bounds.left;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.BOTTOM)
{
px = rightPoint.X - bounds.X + newPoint.X - bounds.X < bounds.Width
? bounds.left
: bounds.right;
points.Add(new Vector(px, py));
points.Add(new Vector(bounds.left, py));
}
}
else if (rightCheck & BoundsCheck.BOTTOM)
{
py = bounds.right;
if (newCheck & BoundsCheck.RIGHT)
{
px = bounds.bottom;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.LEFT)
{
px = bounds.top;
points.Add(new Vector(px, py));
}
else if (newCheck & BoundsCheck.TOP)
{
px = rightPoint.X - bounds.X + newPoint.X - bounds.X < bounds.Width
? bounds.left
: bounds.right;
points.Add(new Vector(px, py));
points.Add(new Vector(bounds.left, py));
}
}
}
if (closingUp)
{
return;
}
points.Add(newPoint);
}
var newRightPoint = newEdge.clippedEnds[LR.Other(newOrientation)];
if (!CloseEnough(points[0], newRightPoint))
{
points.Add(newRightPoint);
}
}
