如何计算圆的直径或半径 [英] How to calculate diameter or radius of the circle

问题描述

if (_shapeChecker.IsCircle(_edgePoint, out _center, out _radius))
            {


                Rectangle[] _rects = _blobCounter.GetObjectsRectangles();

                string _shapeString = "" + _shapeChecker.CheckShapeType(_edgePoint);
                Pen _pen = new Pen(Color.Red, ipenWidth);
                int _x = (int)_center.X;
                int _y = (int)_center.Y;
                _g.DrawString(_shapeString, _font, _brush, _x, _y);
                _g.DrawEllipse(_pen, (float)(_center.X - _radius),
                                     (float)(_center.Y - _radius),
                                     (float)(_radius * 2),
                                     (float)(_radius * 2));

                //size of rectange
                foreach (Rectangle rc in _rects)
                {
                    ///for debug
                    //System.Diagnostics.Debug.WriteLine(
                    //    string.Format("Circle size: ({0}, {1})", rc.Width, rc.Height));

                    iFeatureWidth = rc.Width;
                    double dis = FindDistance(iFeatureWidth);
                    //textBox1.Text = dis.ToString("N2");
                    _g.DrawString(dis.ToString("N2"), _font, _brush, _x, _y + 60);

                    //  textBox1.Text= dis.ToString("N2"), _font, _brush, _x, _y + 60);


                    // get bounding rectangle of the points list
                    IntPoint minXY, maxXY;
                    PointsCloud.GetBoundingRectangle(_edgePoint, out minXY, out maxXY);
                    // get cloud's size
                    IntPoint cloudSize = maxXY - minXY;
                    // calculate center point
                    DoublePoint center = minXY + (DoublePoint)cloudSize / 2;
                    // calculate radius

                        float radius = ((float)cloudSize.X + cloudSize.Y) / 4;
                        textBox2.Text = Convert.ToString(radius);
                        textBox3.Text = dis.ToString();


                }
            }

我是什么尝试过：

What I have tried:

float radius = ((float)cloudSize.X + cloudSize.Y) / 4;
                         textBox2.Text = Convert.ToString(radius);
                         textBox3.Text = dis.ToString();

推荐答案

你以一种猜测工作的方式提出问题。事实证明我很无聊所以我会猜测。



你发现你认为或确定的某个边界是一个圆圈。然后你说：圆的半径是两边的一半。哪个是合乎逻辑的。



你为什么总和X和Y然后除以4呢？它完全没有任何意义，因为它只有在矩形是一个sqaure（X = Y）时才能工作，但在这种情况下只需选择一个并除以2，为什么要费心呢？



这里的主要逻辑问题是你有一个边界RECTANGLE，而不是一个正方形。你应该用最短的一边除以一半，所以

You put the question in a way that is all guess work. It turns out that I'm bored so I will try to guess.

You found the bounding rectangle of something you assume or know for certain is a circle. Then you said: the radius of the circle is half one of the sides. Which is logical.

Why did you sum X and Y and then divided by 4 though? It makes no sense at all as it would work only if the rectangle is actyally a sqaure (X = Y) but in that case just pick one and divide by 2, why bother with a sum?

The main logical problem here is that you have a bounding RECTANGLE, not a square. You should take the shortest of its sides and divide by half, so

float radius = ((float)min(cloudSize.X, cloudSize.Y)) / 2;

（我对C＃框架知之甚少，所以我用 min 作为f它是C ++，使用你喜欢的最小函数。

(I know little of C# framework so I used min as f it was C++, use the minimum function you prefer).

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