Question

我使用WinForm在onPaint事件中提供的简单图形函数创建了一个维恩图。这是我创建维恩的代码。

  using (Brush brushLeft = new SolidBrush(LeftVennColor))
  {
    leftvennPath.AddEllipse(leftVenn);
    leftOnlyRegion = new Region(leftVenn);
    e.Graphics.FillEllipse(brushLeft, leftVenn);
    e.Graphics.DrawEllipse(pen, leftVenn);
  }

  using (Brush brushRight = new SolidBrush(RightVennColor))
  {
    rightvennPath.AddEllipse(rightVenn);
    rightOnlyRegion = new Region(rightVenn);
    e.Graphics.FillEllipse(brushRight, rightVenn);
    e.Graphics.DrawEllipse(pen, rightVenn);
   }

  using (GraphicsPath circle_path = new GraphicsPath())
  {
    circle_path.AddEllipse(leftVenn);
    commonRegion.Intersect(circle_path);
  }

  using (GraphicsPath circle_path = new GraphicsPath())
  {
    circle_path.AddEllipse(rightVenn);
    commonRegion.Intersect(circle_path);
  }

创建了维恩图，但是使用此代码，我的公共区域是左右椭圆的交点。我希望在该公共区域之外有两个独立的区域，这些区域由一条线分开。这是图像，

enter image description here

基本上，我需要将所有这四个区域分开并单击（每个区域的颜色不同）。我在鼠标单击事件中使用Region.IsVisible（e.location）来处理click事件。有人可以帮忙吗？

Answer 1

最终解决方案：

cx0，cy0，radius0 中心和左半径的半径
cx1，cy1，radius1 中心和右圆的半径

该函数通过ref。

获取区域

private void FindRegions(int cx0, int cx1, int cy0, int cy1, int radius0, int radius1, ref Region rgnLeft, ref Region rgnRight)
    {
        //Left circle
        GraphicsPath gpL = new GraphicsPath();
        //Right circle
        GraphicsPath gpR = new GraphicsPath();
        //The right small region (yellow color)
        GraphicsPath gp = new GraphicsPath();
        //Points of intersection
        PointF pnt1 = new PointF();
        PointF pnt2 = new PointF();

        Graphics g = this.CreateGraphics();

        gpL.AddEllipse(new Rectangle(cx0 - radius0, cy0 - radius0, 2 * radius0, 2 * radius0));
        gpR.AddEllipse(new Rectangle(cx1 - radius0, cy1 - radius1, 2 * radius1, 2 * radius1));

        g.DrawPath(Pens.Red, gpL);
        g.DrawPath(Pens.Blue, gpR);

        int numPoints = FindCircleCircleIntersections((single)cx0, (single)cx1, (single)cy0, (single)cy1, (single)radius0, (single)radius1, ref pnt1, ref pnt2);

        if (numPoints != 2)
        {
            //No regions
            return;
        }

        Double theta, fe;
        Double dx = (double)pnt1.X - (double)pnt2.X;
        Double dy = (double)pnt1.Y - (double)pnt2.Y;
        Double dist = Math.Sqrt(dx * dx + dy * dy);

        PointF minPoint, maxPoint;

        if (pnt2.Y < pnt1.Y)
        {
            minPoint = pnt2;
            maxPoint = pnt1;
        }
        else
        {
            minPoint = pnt1;
            maxPoint = pnt2;
        }

        //theta is the angle between the three points pnt1, pnt2 and left center
        theta = Math.Acos((dist / 2D) / 100D);
        theta = (theta * 180D) / Math.PI;
        theta = 90D - theta;
        theta *= 2D;

        //fe is the starting angle of the point(between pnt1 and pnt2) with 
        //the smaller y coordinate. The angle is measured from x axis and clockwise
        fe = Math.Asin( Math .Abs ( (-(Double)minPoint.Y + (double)cy0) )/ (double)radius0);
        fe = (fe * 180D) / Math.PI;

        if (minPoint.X > cx0 && minPoint.Y >= cy0)
        {
            //fe = (90 - fe) + 270;
        }
        else if (minPoint.X > cx0 && minPoint.Y < cy0)
        {
            fe = (90D - fe) + 270D;
        }
        else if (minPoint.X == cx0 && minPoint.Y < cy0)
        {
            fe = 270D;
        }
        else
        {
            fe += 180D;
        }

        gp.AddArc(new Rectangle(cx0 - radius0, cy0 - radius0, 2 * radius0, 2 * radius0), (float)fe, (float)theta);
        gp.AddLine(maxPoint, minPoint);

        gp.CloseFigure();

        g.DrawPath(Pens.Green, gp);

        Region rgnL = new Region(gpL);
        Region rgnR = new Region(gpR);
        Region rgnInt = new Region(gpL);
        Region rgn = new Region(gp); //right small

        rgnInt.Intersect(rgnR);

        rgnInt.Exclude(rgn); //left small

        g.FillRegion(Brushes.DarkGreen, rgnInt);
        g.FillRegion(Brushes.DarkGray, rgn);

        rgnLeft = rgnInt.Clone();
        rgnRight = rgn.Clone();

        g.Dispose();
        rgnL.Dispose();
        rgnR.Dispose();
        rgnInt.Dispose();
        rgn.Dispose();
        gpL.Dispose();
        gpR.Dispose();
        gp.Dispose(); 
    }

    private int FindCircleCircleIntersections(Single cx0, Single cx1, Single cy0, Single cy1, Single radius0, Single radius1, 
                                               ref PointF intersection1, ref PointF intersection2)
    {
        // Find the distance between the centers.
        Single dx = cx0 - cx1;
        Single dy = cy0 - cy1;
        Double dist = Math.Sqrt(dx * dx + dy * dy);

        // See how many solutions there are.
        if (dist > radius0 + radius1) 
        {
            //No solutions, the circles are too far apart.
            intersection1 = new PointF(Single.NaN, Single.NaN);
            intersection2 = new PointF(Single.NaN, Single.NaN);
            return 0;
        }
        else if (dist < Math.Abs(radius0 - radius1))
        {
            // No solutions, one circle contains the other.
            intersection1 = new PointF(Single.NaN, Single.NaN);
            intersection2 = new PointF(Single.NaN, Single.NaN);
            return 0;
        }
        else if ((dist == 0) && (radius0 == radius1)) 
        {
            // No solutions, the circles coincide.
            intersection1 = new PointF(Single.NaN, Single.NaN);
            intersection2 = new PointF(Single.NaN, Single.NaN);
            return 0;
        }
        else
        {
            // Find a and h.
            Double a  = (radius0 * radius0 - radius1 * radius1 + dist * dist) / (2 * dist);
            Double h  = Math.Sqrt(radius0 * radius0 - a * a);

            // Find P2.
            Double cx2 = cx0 + a * (cx1 - cx0) / dist;
            Double cy2 = cy0 + a * (cy1 - cy0) / dist;

            // Get the points P3.
            intersection1 = new PointF( (Single)(cx2 + h * (cy1 - cy0) / dist), (Single)(cy2 - h * (cx1 - cx0) / dist));
            intersection2 = new PointF( (Single)(cx2 - h * (cy1 - cy0) / dist), (Single)(cy2 + h * (cx1 - cx0) / dist));

            // See if we have 1 or 2 solutions.
            if (dist == radius0 + radius1) return 1;
            return 2;
        }
    }

修改

Region 只有 Fill 方法，没有 Draw 方法。所以你不能用地区来做。 GraphicPath 但是 HAS 填充和绘制。
你说你需要验证一个点是否在区域内但是你可以用 GraphicPath

进行相同的操作

myGraphicPath.IsVisible();

所以，不要使用区域而是使用路径。其他原因更好。 GraphicPath 可以绘制 AntiAlias ，但区域不。设置

g.SmoothingMode = SmoothingMode.AntiAlias;

启用 AntiAlias 。所有带路径的好东西！

将函数名称从 FindRegions 更改为 FindPaths ，并将路径作为参考发送：

private void FindPaths(int cx0, int cx1, int cy0, int cy1, int radius0, int radius1, ref GraphicsPath gpLeft, ref GraphicsPath gpRight)

代码完全相同，但添加了和：

private void FindPaths(int cx0, int cx1, int cy0, int cy1, int radius0, int radius1, ref GraphicsPath gpLeft, ref GraphicsPath gpRight)
{
    ...
    ...
    //Above code exactly the same    

    //replace these
    //rgnLeft = rgnInt.Clone();
    //rgnRight = rgn.Clone();

    //with these
    GraphicsPath gpLeftSmall = (GraphicsPath)gp.Clone();
    Matrix matrix = new Matrix();

    PointF pntf = new PointF();

    pntf.X = (float)(Math.Min((double)pnt1.X, (double)pnt2.X) + Math.Abs((double)(pnt1.X - pnt2.X) / 2D));
    pntf.Y = (float)(Math.Min((double)pnt1.Y, (double)pnt2.Y) + Math.Abs((double)(pnt1.Y - pnt2.Y) / 2D));

    matrix.RotateAt(180, pntf);

    gpLeftSmall.Transform(matrix);

    g.DrawPath(Pens.Black, gpLeftSmall); //If you want to draw it

    //passed by refference
    gpLeft = gpLeftSmall.Clone();
    gpRight = gp.Clone();


    g.Dispose();

    rgnL.Dispose();
    rgnR.Dispose();
    rgnInt.Dispose();
    rgn.Dispose();

    gpL.Dispose();
    gpR.Dispose();
    gp.Dispose();
    gpLeftSmall.Dispose();

    matrix.Dispose();   
}

参考： Determine where two circles intersect

使用图形区域定义维恩图的区域

1 个答案: