// Get ready to start.
private void ResetBoundingRect(Vector2[] vertices)
{
_numPoints = vertices.Count();
// Find the minimum and maximum points
// in all four directions.
double minx = vertices[0].X;
double maxx = minx;
double miny = vertices[0].Y;
double maxy = miny;
double minxi = 0;
double maxxi = 0;
double minyi = 0;
double maxyi = 0;
for (int i = 1; i < _numPoints; i++)
{
if (minx > vertices[i].X)
{
minx = vertices[i].X;
minxi = i;
}
if (maxx < vertices[i].X)
{
maxx = vertices[i].X;
maxxi = i;
}
if (miny > vertices[i].Y)
{
miny = vertices[i].Y;
minyi = i;
}
if (maxy < vertices[i].Y)
{
maxy = vertices[i].Y;
maxyi = i;
}
}
_controlPoints[0] = (int)minxi;
_controlPoints[1] = (int)maxyi;
_controlPoints[2] = (int)maxxi;
_controlPoints[3] = (int)minyi;
_currentControlPoint = -1;
// Reset the current and best bounding rectangle.
_currentRectangle = new Vector2[]
{
new Vector2(minx, miny),
new Vector2(maxx, miny),
new Vector2(maxx, maxy),
new Vector2(minx, maxy),
};
var currentArea = (maxx - minx) * (maxy - miny);
_bestRectangle = _currentRectangle;
_bestArea = currentArea;
// So far we have not checked any edges.
_edgeChecked = new bool[_numPoints];
for (int i = 0; i < _numPoints; i++)
{
_edgeChecked[i] = false;
}
}
public Rectangle2(Vector2[] vertices)
{
if (vertices == null) throw new ArgumentNullException("vertices");
if (vertices.Count() != 4) throw new ArgumentException("You must submit 4 vertices!");
if (!IsRectangle(vertices))
{
throw new ArgumentOutOfRangeException("vertices", "The given vertices must form a rectangle in 2D space!");
}
_rect = new Polygon2(vertices);
}
/// <summary>
/// Checks if the given 4 vertices form a rectangle
/// </summary>
/// <param name="vertices"></param>
/// <returns></returns>
public static bool IsRectangle(Vector2[] vertices, double tolerance = GeometrySettings.DEFAULT_TOLERANCE)
{
if (vertices == null) throw new ArgumentNullException("vertices");
if (vertices.Count() != 4) throw new ArgumentException("You must submit 4 vertices!");
var topLine = new LineSegment2(vertices[0], vertices[1]).ToVector();
var rightLine = new LineSegment2(vertices[1], vertices[2]).ToVector();
var bottomLine = new LineSegment2(vertices[2], vertices[3]).ToVector();
var leftLine = new LineSegment2(vertices[3], vertices[0]).ToVector();
// Check that two lines have equal length
if (Math.Abs(topLine.Length - bottomLine.Length) < tolerance
&& Math.Abs(rightLine.Length - leftLine.Length) < tolerance)
{
// Now ensure that the lines are orthogonal on each other
bool isRect = topLine.IsPerpendicularTo(rightLine, tolerance);
isRect &= rightLine.IsPerpendicularTo(bottomLine, tolerance);
isRect &= bottomLine.IsPerpendicularTo(leftLine, tolerance);
return isRect;
}
return false;
}
