我有一个由pointf数组定义的图形路径(由鼠标单击创建),该图由graphics.drawcurve绘制。然后将路径转换为旋转起始和端点为0度。转换的和旋转的曲线(和原始曲线)点F阵列仍可可用。
我需要找到从路径的直线末端的最长垂直距离指向曲线本身。
转换的输出示例
由于我旋转了曲线,找到最长的距离应该与边界的高度相同...但是我还需要知道0轴沿什么距离(现在是什么)如果我能找到曲线,请轻松。我已经搜索了很广泛的搜索 - 我尝试了自定义的样条函数来尝试沿着曲线获得更多固定点,但是最终以相同的结果结束 - 我不知道要点之间的曲线是什么,那就是考虑到两点之间的插值,可能是90%。
现在它已经旋转了,我尝试了一个用于循环的循环,并且在每列中,试图查看是否可以在转换的路径上进行每个点,但是它总是返回false。
。输入点(参考):{x = 499,y = 64} {x = 305,y = 117} {x = 149,y = 114}
(从左到右,我知道我需要进行一些检查以查看以后输入的方式,但是就目前而言,只是试图使其正常工作)
GraphicsPath gP = new GraphicsPath();
gP.AddCurve(lPoints.ToArray());
Graphics g = pbImage.CreateGraphics();
g.SmoothingMode = SmoothingMode.AntiAlias;
//draws original curve (hiding for now to validate and visualize rotation:
//g.DrawPath(new Pen(Color.Blue, 1.75f), gP);
//g.DrawLine(new Pen(Color.Red, 1.75f), lPoints[0], lPoints[lPoints.Count - 1]);
// get angle in radians
double theta2 = Math.Atan2(lPoints[0].Y - lPoints[lPoints.Count - 1].Y, lPoints[0].X - lPoints[lPoints.Count - 1].X);
// convert radians to degrees
double angle = -1 * (theta2 * (180.0 / Math.PI));
//set a new path to the old one, to keep both sets of data
GraphicsPath newPath = gP;
//create rotational matrix, and transform
Matrix m = new Matrix();
m.RotateAt(Convert.ToSingle(angle), lPoints[0]);
newPath.Transform(m);
//draw transformed path to picture box
g.DrawPath(new Pen(Color.Green, 1f), newPath);
//get new points from transformed curve (interestingly enough, it adds more points than the oringial input)
PointF[] tP = newPath.PathPoints;
//create some temp variables to make the next section easier
PointF pS = tP[0];
PointF pE = tP[tP.Length - 1];
//draw the straight line for visual validation
g.DrawLine(new Pen(Color.Red, 1f), pS, pE);
//get the bounds of the new path
RectangleF bRect = newPath.GetBounds();
a
// loop through x's
for (float i = pE.X; i < pS.X; i = i + 5)
{
float h = pS.Y - bRect.Y;
bool bFound = false;
// loop through y's - do loop until found
do
{
if (newPath.IsVisible(i, h, g))
{
// never found
tbOutPt.Text = tbOutPt.Text + "found!!!!";
bFound = true;
}
h++;
} while (bFound = false && h < bRect.Height);
}
我唯一能想到的另一件事就是根据界限创建一个新的位图,重新曲线,然后按列逐列,并获取像素颜色,直到与颜色匹配曲线的颜色,。
希望某人有一个更好的解决方案。
Flatten()
图形路径,然后使用标准的"点到线距离"测量来找到最大的距离:
private float PointToLineDist(float Px, float Py, float Ax, float Ay, float Bx, float By)
{
float q = 0;
if ((Ax == Bx) & (Ay == By)) {
// A and B passed in define a point, not a line.
// Point to Point Distance
return PointToPointDist(Px, Py, Ax, Ay);
} else {
// Distance is the length of the line needed to connect the point to
// the(segment)such that the two lines would be perpendicular.
// q is the parameterized value needed to get to the intersection
q = ((Px - Ax) * (Bx - Ax) + (Py - Ay) * (By - Ay)) / ((Bx - Ax) * (Bx - Ax) + (By - Ay) * (By - Ay));
// Limit q to 0 <= q <= 1
// If q is outside this range then the Point is somewhere past the
// endpoints of our segment. By setting q = 0 or q = 1 we are
// measuring the actual distacne from the point to one of the
// endpoints(instead)
if (q < 0)
q = 0;
if (q > 1)
q = 1;
// Distance
return PointToPointDist(Px, Py, (1 - q) * Ax + q * Bx, (1 - q) * Ay + q * By);
}
}
private float PointToPointDist(float Ax, float Ay, float Bx, float By)
{
// PointToPointDist = SquareRoot((Bx - Ax)^2 + (By - Ay)^2)
return Math.Sqrt((Bx - Ax) * (Bx - Ax) + (By - Ay) * (By - Ay));
}
在PointToLineDist()
中,(PX,PY)是问题所在的点,(AX,AY),(BX,BY)是行段的端点。
这是将来的代码:
private void processArray()
{
// this is for demo only - real points should come from mouse input, or otherwise
PointF[] inputArray = new PointF[2];
inputArray[0] = new PointF(537, 147);
inputArray[1] = new PointF(334, 180);
inputArray[2] = new PointF(150, 167);
GraphicsPath gP = new GraphicsPath();
gP.AddCurve(inputArray);
Graphics g = pbImage.CreateGraphics();
g.SmoothingMode = SmoothingMode.AntiAlias;
//draws original curve
g.DrawPath(new Pen(Color.Blue, 1.75f), gP);
// draw a straight line between the ends of the curve
//g.DrawLine(new Pen(Color.Red, 1.75f), lPoints[0], lPoints[lPoints.Count - 1]);
// create second path to flatten
GraphicsPath pathFlat = gP;
pathFlat.Flatten();
// get list of points to step through
PointF[] fP = pathFlat.PathPoints;
//variables to store max distance
float maxDistance = 0;
PointF maxDistP = new PointF(0, 0);
foreach (PointF p in fP)
{
// get the distance from the point to the closet point on the line segment
float curDist = PointToLineDist(p.X, p.Y, lPoints[0].X, lPoints[0].Y, lPoints[lPoints.Count - 1].X, lPoints[lPoints.Count - 1].Y);
// check the value against and store the longest point
if (curDist > maxDistance)
{
maxDistance = curDist;
maxDistP = new PointF(p.X, p.Y);
}
}
// mark a dot at the longest point
g.DrawRectangle(new Pen(Color.Red), new Rectangle(Convert.ToInt32(maxDistP.X), Convert.ToInt32(maxDistP.Y), 2, 2
}
此功能都应该被包装到类中,以便您可以创建和编辑图形路径并根据需要获取其属性。