Is there any possibility to plot a circle in a WindowsForm Chart?
A method-call as follows would be really nice!
Graph.Series["circle"].Circle.Add(centerX, centerY, radius);
Well, I created myself a work around.
Maybe it helps someone
public void DrawCircle(Chart Graph, double centerX, double centerY, double radius, int amountOfEdges)
{
string name = "circle_" + centerX + centerY + radius + amountOfEdges;
// Create new data series
if (Graph.Series.IndexOf(name) == -1)
Graph.Series.Add(name);
// preferences of the line
Graph.Series[name].ChartType = SeriesChartType.Spline;
Graph.Series[name].Color = Color.FromArgb(0, 0, 0);
Graph.Series[name].BorderWidth = 1;
Graph.Series[name].IsVisibleInLegend = false;
// add line segments (first one also as last one)
for (int k = 0; k <= amountOfEdges; k++)
{
double x = centerX + radius * Math.Cos(k * 2 * Math.PI / amountOfEdges);
double y = centerY + radius * Math.Sin(k * 2 * Math.PI / amountOfEdges);
Graph.Series[name].Points.AddXY(x, y);
}
}
You can call it for example via
DrawCircle(Graph, 5, 4, 3, 30);
Around 30 points should be enough to get a nice circle instead of a polygon, but depends on the size of your chart.
Related
Good evening, I know on the web there are similar questions and a few tutorials about it, but I'd like you to check my code and correct it. I mean, I'd like to know what's wrong with my project.
I have to draw a parabola graph given its equation on my main panel.
I also must include two buttons, zoom in and zoom out, which are used to reduce and enlarge the "view" panel's view (and so the parabola).
I was recommended to use a scale var.
This is my code:
note: x0, y0 are panel_main x center, y center.
I have x, y that are used to determine x,y from the equation.
xpc, ypc are converted for the window scale (so are pixels).
xmin, xmax are the extreme values that, with a certain scale, stay on the panel
I hope you can give me a hint, thanks a lot!
public void DisegnaParabola()
{
Graphics gs = panel_main.CreateGraphics();
pen.Color = Color.Black;
scale = (x0*2) / zoom; //Pixels equivalent to 1x or 1y
n_punti = (x0*2) / scale; //Number of x math points that are visible in window
xmin = -(n_punti / 2);
xmax = n_punti / 2;
precision = 1 / scale; //Increment of x to have 1px
if (asse_parabola.SelectedIndex == 0) //if Y axis
{
for (double i = xmin + precision; i < xmax; i += precision)
{
rifx = i - precision; //Old points
rifxpc = rifx * scale;
rify = (a * Math.Pow(rifx, 2)) + b * rifx + c;
rifypc = y0 - (rify * scale);
x = i; //New points
y = (a * Math.Pow(x, 2)) + b * x + c;
ypc = y0 - (y * scale);
gs.DrawLine(pen, (float)rifxpc, (float)rifypc, (float)xpc, (float)ypc);
}
}
else
{
scale = (y0*2) / zoom; //Pixels for 1y
n_punti = (y0*2) / scale; //Numbers of y in the window
ymin = -(n_punti / 2);
ymax = n_punti / 2;
for(double i=ymin+precision; i<ymax; i+=precision)
{
rify = y - precision;
rifypc = (y0*2) - rify * scale;
rifx = (a * Math.Pow(rify, 2)) + b * rify + c;
rifxpc = x0 + (rifx * scale);
y = i;
x = (a * Math.Pow(y, 2)) + b * y + c;
xpc = x0 + (x * scale);
gs.DrawLine(pen, (float)rifypc, (float)rifxpc, (float)ypc, (float)xpc);
}
}
lbl_canc.Visible = true;
}
Your question actually consists of several tasks and as usual the key is to take and break those apart..
One issue is getting the data, I will leave the details to you but show how to sparate it from the rest.
The next issue is to scale the data. I'll show you how to avoid this one altogether and scale the drawing tool instead.
And the third one is to draw them to a display surface. As you'll see this is really simple once the other issues are taken care of.
Let's start with the most important step: Collecting the data. You try to create and scale and draw them all in the same piece of code. This has many disadvantages..
Let's first collect the data in a suitable structure:
List<PointF> points = new List<PointF>();
List<T> is the collection of choice most of the time; certainly much nicer than arrays! In some method you should fill that list with your data, calculated from some formula.
Here is an example:
List<PointF> getPoints(float start, float end, int count, float ymax)
{
List<PointF> points = new List<PointF>();
float deltaX = (end - start) / count;
for (int i = 0; i < count; i++)
{
float x = i * deltaX;
// insert your own formula(s) here!
float y = ymax + (float)Math.Sin(x * somefactor) * ymax;
points.Add(new PointF(x, y));
}
return points;
}
Now for the second important part: How to scale the data? This can be done either when creating them; but again, separating the two taks makes them both a lot simpler.
So here is a function that, instead of scaling the data scales the Graphics object we will use to plot them:
void ScaleGraphics(Graphics g, List<PointF> data)
{
float xmax = data.Select(x => x.X).Max();
float ymax = data.Select(x => x.Y).Max();
float xmin = data.Select(x => x.X).Min();
float ymin = data.Select(x => x.Y).Min();
float width = Math.Abs(xmax - xmin);
float height = Math.Abs(ymax - ymin);
var vr = g.VisibleClipBounds;
g.ScaleTransform(vr.Width / width, vr.Height / height);
}
This method makes sure that all the data in our list will fit into the drawing surface. If you want to restrict them to a different size you can pass it in and change the code accordingly..
Finally we need to do the actual drawing. We do that where we should, that is in the Paint event of our drawing surface control..:
private void panel1_Paint(object sender, PaintEventArgs e)
{
if (points.Count < 2) return; // no lines to draw, yet
ScaleGraphics(e.Graphics, points);
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
using ( Pen pen = new Pen(Color.Blue )
{ Width = 1.5f , LineJoin = LineJoin.Round, MiterLimit = 1f} )
e.Graphics.DrawLines(pen, points.ToArray());
}
The title for this post was quite hard to think of, so if you can think of a more descriptive title please tell me. Anyway, my problem is quite specific and requires some simple maths knowledge. I am writing a C# WinForms application which is a bit like the old 'xeyes' Linux application. It basically is a set of eyes which follow around your mouse cursor. This may sound easy at first, however can get rather complicated if you're a perfectionist like me :P. This is my code so far (only the paint method, that is called on an interval of 16).
int lx = 35;
int ly = 50;
int rx;
int ry;
int wx = Location.X + Width / 2;
int wy = Location.Y + Height / 2;
Rectangle bounds = Screen.FromControl(this).Bounds;
// Calculate X
float tempX = (mx - wx) / (float)(bounds.Width / 2);
// Calculate Y
float tempY = (my - wy) / (float)(bounds.Height / 2);
// Draw eyes
e.Graphics.FillEllipse(Brushes.LightGray, 10, 10, 70, 100);
e.Graphics.FillEllipse(Brushes.LightGray, 90, 10, 70, 100);
// Draw pupils (this only draws the left one)
e.Graphics.FillEllipse(Brushes.Black, lx += (int)(25 * tempX), ly += (int)(40 * tempY), 20, 20);
Now this does work at a basic level, however sometimes this can happen if the user puts the cursor at 0,0.
Now my question is how to fix this? What would the IF statement be to check where the mouse pointer is, and then reduce the pupil X depending on that?
Thanks.
Edit: This is where I get the mouse positions (my and mx):
private void timer_Tick(object sender, EventArgs e)
{
mx = Cursor.Position.X;
my = Cursor.Position.Y;
Invalidate();
}
The timer is started in the eyes_Load event and the interval is 16.
Edit 2: Final solution: http://pastebin.com/fT5HfiQR
Modelling the eyeball as the following ellipse:
Its equation is:
And that of the line joining its center and the cursor:
(don't worry about the singularity)
We can then solve to get the intersection point:
Where
Now you can calculate the distance to the eyeball's edge, by dividing the distance from the center to the cursor by sigma. What remains is just interpolating to cap the position of the pupil:
The if statement you want is then
(N.B. for math-mo's out there the above was a slight simplification, which assumes your ellipse is not too narrow; the exact solution is non-analytical)
EDIT: my tests in VB.NET:
EDIT 2: C# port
PointF Bound(double xc, double yc, double w, double h, double xm, double ym, double r)
{
double dx = xm - xc, dy = ym - yc;
if (Math.Abs(dx) > 0.001 && Math.Abs(dy) > 0.001)
{
double dx2 = dx * dx, dy2 = dy * dy;
double sig = 1.0 / Math.Sqrt(dx2 / (w * w * 0.25) + dy2 / (h * h * 0.25));
double d = Math.Sqrt(dx2 + dy2), e = d * sig;
if (d > e - r)
{
double ratio = (e - r) / d;
return new PointF((float)(xc + dx * ratio),
(float)(yc + dy * ratio));
}
}
return new PointF((float)xm, (float)ym);
}
xc, yc: Center coordinates of the ellipse
w, h: Width and height of the ellipse
xm, ym: Mouse coordinates
r: Radius of the circle you wanna constrain (the pupil)
Returns: The point where you wanna place the center of the circle
EDIT 3: Many thanks to Quinchilion for the following optimization (gawd damn this smacked me hard in the face)
PointF Bound(double xc, double yc, double w, double h, double xm, double ym, double r)
{
double x = (xm - xc) / (w - r);
double y = (ym - yc) / (h - r);
double dot = x*x + y*y;
if (dot > 1) {
double mag = 1.0 / Math.Sqrt(dot);
x *= mag; y *= mag;
}
return new PointF((float)(x * (w - r) + xc), (float)(y * (h - r) + yc));
}
I've been trying to recode a C++ DirectX code to C# that would help me with Drawing a perfect circle. Currently I have this code that i translated by myself:
private void Circle(int X, int Y, int radius, int numSides, Color color)
{
Vector2[] Line = new Vector2[128];
float Step = (float)(Math.PI * 2.0 / numSides);
int Count = 0;
for (float a = 0; a < Math.PI * 2.0; a += Step)
{
float X1 = (float)(radius * Math.Cos(a) + X);
float Y1 = (float)(radius * Math.Sin(a) + Y);
float X2 = (float)(radius * Math.Cos(a + Step) + X);
float Y2 = (float)(radius * Math.Sin(a + Step) + Y);
Line[Count].X = X1;
Line[Count].Y = Y1;
Line[Count + 1].X = X2;
Line[Count + 1].Y = Y2;
Count += 2;
}
line.Begin();
line.Draw(Line, color);
line.End();
}
The problem is that the circle is drawn but also a Line from a point in the circle to the left top corner, like this.
Don't iterate with a floating point variable. They might get imprecise during the iteration. In your case, the last step is probably very close behind the upper bound (instead of hitting it exactly). So it won't get calculated and left as the default (0, 0).
So use an integer iteration variable:
for (int i = 0; i < numSides; ++i)
{
float a = i * Step;
...
}
Then, you can also get rid of Count.
Furthermore, you should make your coordinate buffer dynamic:
Vector2[] Line = new Vector2[2 * numSides];
i am currently try to inscribe diagonals of a decagon inside a circle
like this
in c# my approach would be creating a circle
e.Graphics.DrawEllipse(myPen, 0, 0, 100, 100);
and draw lines inside using
e.Graphics.DrawLine(myPen, 20, 5, 50, 50);
after that i would draw a decagon polygon.
currently im stuck at how to divide the circle into 10 parts/ finding the correct coordiantes of the points on the circumference of the circles because im not good in math,
i want to know how would i know the next point in a circumference of the circle the size of my circle is indicated above.
and also i want also to ask a better approach for my problem.
Thank you :)
Just for grits and shins, here's a generic implementation that will inscribe an X-sided polygon into the Rectangle you pass it. Note that in this approach I'm not actually calculating any absolute points. Instead, I am translating the origin, rotating the surface, and drawing the lines only with respect to the origin using a fixed length and an angle. This is repeated in a loop to achieve the end result below, and is very similar to commanding the Turtle in Logo:
public partial class Form1 : Form
{
PictureBox pb = new PictureBox();
NumericUpDown nud = new NumericUpDown();
public Form1()
{
InitializeComponent();
this.Text = "Inscribed Polygon Demo";
TableLayoutPanel tlp = new TableLayoutPanel();
tlp.RowCount = 2;
tlp.RowStyles.Clear();
tlp.RowStyles.Add(new RowStyle(SizeType.AutoSize));
tlp.RowStyles.Add(new RowStyle(SizeType.Percent, 100));
tlp.ColumnCount = 2;
tlp.ColumnStyles.Clear();
tlp.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
tlp.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
tlp.Dock = DockStyle.Fill;
this.Controls.Add(tlp);
Label lbl = new Label();
lbl.Text = "Number of Sides:";
lbl.TextAlign = ContentAlignment.MiddleRight;
tlp.Controls.Add(lbl, 0, 0);
nud.Minimum = 3;
nud.Maximum = 20;
nud.AutoSize = true;
nud.ValueChanged += new EventHandler(nud_ValueChanged);
tlp.Controls.Add(nud, 1, 0);
pb.Dock = DockStyle.Fill;
pb.Paint += new PaintEventHandler(pb_Paint);
pb.SizeChanged += new EventHandler(pb_SizeChanged);
tlp.SetColumnSpan(pb, 2);
tlp.Controls.Add(pb, 0, 1);
}
void nud_ValueChanged(object sender, EventArgs e)
{
pb.Refresh();
}
void pb_SizeChanged(object sender, EventArgs e)
{
pb.Refresh();
}
void pb_Paint(object sender, PaintEventArgs e)
{
// make circle centered and 90% of PictureBox size:
int Radius = (int)((double)Math.Min(pb.ClientRectangle.Width, pb.ClientRectangle.Height) / (double)2.0 * (double).9);
Point Center = new Point((int)((double)pb.ClientRectangle.Width / (double)2.0), (int)((double)pb.ClientRectangle.Height / (double)2.0));
Rectangle rc = new Rectangle(Center, new Size(1, 1));
rc.Inflate(Radius, Radius);
InscribePolygon(e.Graphics, rc, (int)nud.Value);
}
private void InscribePolygon(Graphics G, Rectangle rc, int numSides)
{
if (numSides < 3)
throw new Exception("Number of sides must be greater than or equal to 3!");
float Radius = (float)((double)Math.Min(rc.Width, rc.Height) / 2.0);
PointF Center = new PointF((float)(rc.Location.X + rc.Width / 2.0), (float)(rc.Location.Y + rc.Height / 2.0));
RectangleF rcF = new RectangleF(Center, new SizeF(1, 1));
rcF.Inflate(Radius, Radius);
G.DrawEllipse(Pens.Black, rcF);
float Sides = (float)numSides;
float ExteriorAngle = (float)360 / Sides;
float InteriorAngle = (Sides - (float)2) / Sides * (float)180;
float SideLength = (float)2 * Radius * (float)Math.Sin(Math.PI / (double)Sides);
for (int i = 1; i <= Sides; i++)
{
G.ResetTransform();
G.TranslateTransform(Center.X, Center.Y);
G.RotateTransform((i - 1) * ExteriorAngle);
G.DrawLine(Pens.Black, new PointF(0, 0), new PointF(0, -Radius));
G.TranslateTransform(0, -Radius);
G.RotateTransform(180 - InteriorAngle / 2);
G.DrawLine(Pens.Black, new PointF(0, 0), new PointF(0, -SideLength));
}
}
}
I got the formula for the length of the side here at Regular Polygon Calculator.
One way of dealing with this is using trigonometric functions sin and cos. Pass them the desired angle, in radians, in a loop (you need a multiple of 2*π/10, i.e. a = i*π/5 for i between 0 and 9, inclusive). R*sin(a) will give you the vertical offset from the origin; R*cos(a) will give you the horizontal offset.
Note that sin and cos are in the range from -1 to 1, so you will see both positive and negative results. You will need to add an offset for the center of your circle to make the points appear at the right spots.
Once you've generated a list of points, connect point i to point i+1. When you reach the ninth point, connect it to the initial point to complete the polygon.
I don't test it, but i think it is ok.
#define DegreeToRadian(d) d * (Pi / 180)
float r = 1; // radius
float cX = 0; // centerX
float cY = 0; // centerY
int numSegment = 10;
float angleOffset = 360.0 / numSegment;
float currentAngle = 0;
for (int i = 0; i < numSegment; i++)
{
float startAngle = DegreeToRadian(currentAngle);
float endAngle = DegreeToRadian(fmod(currentAngle + angleOffset, 360));
float x1 = r * cos(startAngle) + cX;
float y1 = r * sin(startAngle) + cY;
float x2 = r * cos(endAngle) + cX;
float y2 = r * sin(endAngle) + cY;
currentAngle += angleOffset;
// [cX, cY][x1, y1][x2, y2]
}
(fmod is c++ function equals to floatNumber % floatNumber)
I am developing a small program, and to generate the coordenates I am using this code:
public double[] GenerateNewCircle(int maxSize, int numberOfBalls, double centerx, double centery)
{
double[] position = null;
double angle = 360 / 6;
double angleRad = DegreeToRadian(incrementAngle);
position = CalculatePosition(radiusX, radiusY, centerx, centery, angleRad);
return position;
}
public double[] CalculatePosition(double radiusX, double radiusY, double centerX, double centerY, double angle)
{
double[] position = new double[2];
position[0] = Math.Cos(angle) * (radiusX + centerX)*1.5;
position[1] = Math.Sin(angle) * (radiusY + centerY)*1.5;
return position;
}
To check if not overlapping or if is in the area I used this
bool circleIsAllowed(List<Circle> circles, Circle newCircle)
{
if (newCircle.x < 10 || newCircle.x > pictureBox1.Width)
return false;
if (newCircle.y < 9 || newCircle.y > pictureBox1.Height)
return false;
foreach (Circle it in circles)
{
double aX = Math.Pow(it.x - newCircle.x, 2);
double aY = Math.Pow(it.y - newCircle.y, 2);
double Dif = Math.Abs(aX - aY);
double ra1 = it.r / 2;
double ra2 = it.r / 2;
double raDif = Math.Pow(ra1 + ra2, 2);
if ((raDif + 1) > Dif) return false;
}
return true; // no existing circle overlaps
}
I have two problems right now
It blocks because is also trying to generate a circle around it, when is a space near.
How can I increase the distance between the circles? They are too close.
This circles is to draw around a circle (around it)
This is the image:
There is mistake in second code block. Try this:
double aX = Math.Pow(it.x - newCircle.x, 2);
double aY = Math.Pow(it.y - newCircle.y, 2);
double distance = Math.Pow(aX + aY, 0.5); // distance between circles centers
double ra1 = it.r / 2;
double ra2 = it.r / 2;
// is it.r diameter? if so, then ok, else div by 2 is useless
double circlesDistance = 10; // distance between circles (not centers)
if (distance < ra1 + ra2 + circlesDistance)
{
return false;
}
To compute the distance between two circle centers, you should apply the Pythagorean Theorem:
a2 + b2 = c2.
This works perfectly if we have circles (with ellipses you'd have to compute their radius along the connection between their centres which would involve some sinus and cosinus computations).
double aX = Math.Pow(it.x - newCircle.x, 2);
double aY = Math.Pow(it.y - newCircle.y, 2);
if ((aX + aY) <= Math.Pow(it.r + newCircle.r, 2)) {
return false;
}