问题描述
我搜索了所有互联网,但没有找到任何伪代码可以解决此问题,
我想使用5个参数在A和B两点之间找到一条弧:
I searched all internet and didn't find any pseudo code that solved this problem,I want to find an Arc between two points, A and B, using 5 arguments:
- 起点
- 终点
- 半径(不知道是否需要这样做) )
- 角度
- 质量
- Start Point
- End Point
- Radius (Don't know if this is needed)
- Angle
- Quality
示例:
起点=左侧的绿点是在参数上设置的起点
StartPoint = The green point on the left is the Start Point set on the arguments
终点=绿点右边是在参数上设置的终点
EndPoint = The green point on the right is the End Point set on the arguments
角度=圆弧(半圆)的角度
Angle = Angle of the Arc(Semi Circle)
质量=要创建多少个红色圆圈
Quality = How many red circles to create
我想使用伪代码来解决此问题
I would like to have a pseudo code to solve this problem
谢谢预先:D
推荐答案
让起点为P0,终点为P1,角度为Fi。 不需要R
Let start point is P0, end point P1, angle Fi. R is not needed
首先找到弧中心。获取P0-P1段的中间位置。
At first find arc center. Get middle of P0-P1 segment.
M = (P0 + P1) / 2
// M.x = (P0.x + P1.x) / 2 , same for y
和方向矢量相同
D = (P1 - P0) / 2
获取D的长度
lenD = Math.Hypot(D.x, D.y) //Vector.Length, sqrt of sum of squares
获取单位向量
uD = D / lenD
获取(左)垂直向量
(P.x, P.y) = (-uD.y, ud.x)
现在的圆心
if F = Pi then
C.x = M.x
C.y = M.y
else
C.x = M.x + P.x * Len / Tan(Fi/2)
C.y = M.y + P.y * Len / Tan(Fi/2)
从中心到起点的向量:
CP0.x = P0.x - C.x
CP0.y = P0.y - C.y
然后可以使用向量CP0绕中心点旋转计算圆弧上N个中间点的坐标
Then you can calculate coordinates of N intermediate points at the arc using rotation of vector CP0 around center point
an = i * Fi / (NSeg + 1);
X[i] = C.x + CP0.x * Cos(an) - CP0.y * Sin(an)
Y[i] = C.y + CP0.x * Sin(an) + CP0.y * Cos(an)
工作的Delphi代码
Working Delphi code
procedure ArcByStartEndAngle(P0, P1: TPoint; Angle: Double; NSeg: Integer);
var
i: Integer;
len, dx, dy, mx, my, px, py, t, cx, cy, p0x, p0y, an: Double;
xx, yy: Integer;
begin
mx := (P0.x + P1.x) / 2;
my := (P0.y + P1.y) / 2;
dx := (P1.x - P0.x) / 2;
dy := (P1.y - P0.y) / 2;
len := Math.Hypot(dx, dy);
px := -dy / len;
py := dx / len;
if Angle = Pi then
t := 0
else
t := len / Math.Tan(Angle / 2);
cx := mx + px * t;
cy := my + py * t;
p0x := P0.x - cx;
p0y := P0.y - cy;
for i := 0 to NSeg + 1 do begin
an := i * Angle / (NSeg + 1);
xx := Round(cx + p0x * Cos(an) - p0y * Sin(an));
yy := Round(cy + p0x * Sin(an) + p0y * Cos(an));
Canvas.Ellipse(xx - 3, yy - 3, xx + 4, yy + 4);
end;
end;
的结果(Point(100,0),Point(0,100 ),Pi / 2、8
(图片的Y轴向下)
这篇关于几何弧算法的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!