旋轉矩形的點位置

Question

我有一個我想要旋轉的矩形。

我只有矩形的一個點（鼠標位置），矩形的長度和寬度以及旋轉的角度。現在我需要矩形的其他三個角的位置，以便我可以使用Graphics.DrawPolygon（）輕鬆繪製我的矩形。

我不知道，因爲我沒有好幾年的數學和需要你的幫助：d

我試圖從互聯網，但沒有許多解決方案真正適合我的問題。

Answer 1

下面的課程是你正在尋找的。作爲參考，看看旋轉如何工作：http://en.wikipedia.org/wiki/Rotation_matrix

public class MyRectangle 
{ 
    public double Length { get; set; } 
    public double Width { get; set; } 
    public double Rotation { get; private set; } 
    public Coord Center { get; private set; } 
    public Coord TopLeft { get; private set; } 
    public Coord TopRight { get; private set; } 
    public Coord BottomLeft { get; private set; } 
    public Coord BottomRight { get; private set; } 

    public MyRectangle(Coord origin, double length, double width) 
    { 
     Length = length; 
     Width = width; 
     Center = origin; 

     BottomLeft = new Coord(Center.X - Width/2, Center.Y - Length/2); 
     BottomRight = new Coord(Center.X + Width/2, Center.Y - Length/2); 
     TopLeft = new Coord(Center.X - Width/2, Center.Y + Length/2); 
     TopRight = new Coord(Center.X + Width/2, Center.Y + Length/2); 
    } 

    private void Move(Coord c) 
    { 

     InitCorners(new Coord((c.X - Center.X), (c.Y - Center.Y))); 
     Center.X = Center.X + (c.X - Center.X); 
     Center.Y = Center.Y + (c.Y - Center.Y); 
    } 

    private void InitCorners(Coord c) 
    { 
     BottomRight.X = (BottomRight.X + c.X); 
     BottomRight.Y = (BottomRight.Y + c.Y); 

     BottomLeft.X = (BottomLeft.X + c.X); 
     BottomLeft.Y = (BottomLeft.Y + c.Y); 

     TopRight.X = (TopRight.X + c.X); 
     TopRight.Y = (TopRight.Y + c.Y); 

     TopLeft.X = (TopLeft.X + c.X); 
     TopLeft.Y = (TopLeft.Y + c.Y); 
    } 

    public void Rotate(double qtyRadians) 
    { 
     //Move center to origin 
     Coord temp_orig = new Coord(Center.X, Center.Y); 
     Move(new Coord(0, 0)); 

     BottomRight = RotatePoint(BottomRight, qtyRadians); 
     TopRight = RotatePoint(TopRight, qtyRadians); 
     BottomLeft = RotatePoint(BottomLeft, qtyRadians); 
     TopLeft = RotatePoint(TopLeft, qtyRadians); 

     //Move center back 
     Move(temp_orig); 
    } 

    Coord RotatePoint(Coord p, double qtyRadians) 
    { 
     Coord temb_br = new Coord(p.X, p.Y); 
     p.X = temb_br.X * Math.Cos(qtyRadians) - temb_br.Y * Math.Sin(qtyRadians); 
     p.Y = temb_br.Y * Math.Cos(qtyRadians) + temb_br.X * Math.Sin(qtyRadians); 

     return p; 
    } 
} 

[DebuggerDisplay("({X},{Y})")] 
public class Coord 
{ 
    public double X { get; set; } 
    public double Y { get; set; } 
    public Coord(double x, double y) 
    { 
     X = x; 
     Y = y; 
    } 
}