Parallel lines & rounded line

AlexB47

Hi ALL, I have a list of point coordinates (x,y) to draw a line. The line is curve. I need to draw 2 parallel line, at left and at right of this line. My scope is to draw a rounded line of intere line. Help me please, with example. Thanks.

Alex

Anurag Gandhi

Could you please make it clear what do you want to do?

AlexB47 wrote:

My scope is to draw a rounded line

Rounded line? Did you mean a Curve??

Anurag Gandhi. http://www.gandhisoft.com Life is a computer program and every one is the programmer of his own life.

dan sh

AlexB47 wrote:

The line is curve

Is it a curve or a straight line?

AlexB47 wrote:

My scope is to draw a rounded line of intere line

You mean circle? Graphics class has methods like DrawLine, DrawCurve and DrawEllipse. Read about them and you should be able to do this. Make sure you do your drawing in the Paint event and use PaintEventArgs.Graphics object to draw. Drawing the parallel lines should be simple: get the X coordinate of the "end" from where you need to draw the parallel line. Then with same X coordinate, just change the Y and draw the line. Choice of Y coordinate would depend on the length of the parallel line segment you need to draw.

50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong...!!

AlexB47

curved line. I have to build 2 parallel lines of a GPS track (so curved path). Building a sort of lane of the road. :)

Alex

Rob Philpott

That's tricky. You can only draw lines on the left and the right when the road runs north to south. With east to west, you'd need to draw them top and bottom. I think you're going to be need some trigonometry to do this. You could probably cheat by drawing a thick line and overlaying a thin line and let windows do the rounding of intersections. Are you in GDI or WPF?

Regards, Rob Philpott.

AlexB47

in GDI (I use DrawLine etc...).

Alex

AlexB47

read below...

Alex

Rob Philpott

Ok, using the 'hack' mentioned above, create a new windows forms application in visual studio, and add the following in form1.cs

protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);

GraphicsPath p = new GraphicsPath(FillMode.Alternate);
p.AddLine(0, 0, 50, 50);
p.AddLine(50, 50, 60, 50);
p.AddLine(60, 50, 60, 60);
p.AddLine(60, 60, 90, 130);

Pen pen = new Pen(Brushes.Black, 10);
Pen p2 = new Pen(Brushes.White, 4);
e.Graphics.DrawPath(pen, p);
e.Graphics.DrawPath(p2, p);

}

That's one approach...

Regards, Rob Philpott.

Luc Pattyn

yep. that is what I would try, intuitively I would use odd line widths though. :)

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Martin 0

Rob Philpott wrote:

That's one approach...

Which is nice, apart from the fact that you are not .Dispose() the GraphicsPath and Pen instances you created.

All the best, Martin

AlexB47

Thanks.. I try with your solutions ... ;)

Alex

AlexB47

Hello, I have another problem. Is there a way to avoid that the circuit is redrawn below? I to draw the current point that moves, use the DrawEllipse function (current position). How can I avoid soiling the circuit with all subsequent drawEllipse? Thanks.

Alex