How do I draw a stright line which pass the diagonals of the rectangle ?

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I am trying to draw the straight line with DrawLine() method.If someone knows how please help.Thank you.

What I have tried:

public override void DrawSelf(Graphics grfx)
       {
           base.DrawSelf(grfx);

          grfx.FillRectangle(new SolidBrush(FillColor), Rectangle.X, Rectangle.Y, Rectangle.Width, Rectangle.Height);
          grfx.DrawRectangle(Pens.Black,Rectangle.X, Rectangle.Y, Rectangle.Width, Rectangle.Height);

          grfx.DrawLine(Pens.Black, Rectangle.Left, Rectangle.Top, Rectangle.Right, Rectangle.Bottom);
          grfx.DrawLine(Pens.Black, Rectangle.Right , Rectangle.Top , Rectangle.Left, Rectangle.Bottom );
          grfx.DrawLine(Pens.Black, Rectangle.Right, Rectangle.Top, Rectangle.Left+Rectangle.Right, Rectangle.Bottom);

       }

Posted 13-Jun-20 9:23am

Nadi G.

Updated 13-Jun-20 9:32am

v2

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OriginalGriff · Answer 1 · 2020-06-13T09:33:00

Solution 1

I'm not at all sure what you intend that last line to do: but since it starts at the right hand side and goes further right from there it won't be at all visible within the rest of your drawing:

C#

grfx.DrawLine(Pens.Black, Rectangle.Right, Rectangle.Top, Rectangle.Left+Rectangle.Right, Rectangle.Bottom);

Since both left and right will be positive, left + rigth will be greater than right alone (unless left is zero, in which case it's a vertical line you've already drawn).

Posted 13-Jun-20 9:33am

OriginalGriff

Comments

Nadi G. 13-Jun-20 15:53pm

I drawn the diagonals and now i am trying to draw a line which pass the middle of the rectangle.

OriginalGriff 13-Jun-20 15:57pm

A vertical line down the middle would be
X = left + (right - left) / 2, Y = top
to
X = same, Y = bottom.

Nadi G. 13-Jun-20 16:05pm

Thank you.

OriginalGriff 13-Jun-20 17:04pm

You're welcome!

Nadi G. 14-Jun-20 15:41pm

How to draw the line only to the center not all diameter?
I need to take the side/2 and take the half line
sorry for asking but my Math thinking is bad.

OriginalGriff 14-Jun-20 15:56pm

It's really difficult to work out from your description exactly what you want to do: and without that, it's pretty much impossible to tell you.
So ... get a pencil and paper, and draw a rectangle.
Label the horizontal lines L to R, and W as the length. (Left, right width).
Do the same with the verticals: T to B, H.
Now draw your diagonals, and label the centre: it's (L + (R - L) / 2, T + (B - T) / 2)

Now add the lines you are trying to draw, and it should be obvious where they start and finish!.

Nadi G. 14-Jun-20 16:09pm

Thank you.

Nadi G. 1-Jul-20 7:47am

Is there a way to draw triangle with Polygon method but using Recatngle(.Width,.Height,.X,.Y)?

Nadi G. 1-Jul-20 7:48am

I know i can draw it with points[] but i want to draw it with Rectangle class because i want to put lines in it

OriginalGriff 1-Jul-20 8:00am

No, because the Rectangle class always defines four sided objects. That's part of the definition of a Rectangle: four sides, no more, no less.

Nadi G. 2-Jul-20 7:23am

base.DrawSelf(grfx);
System.Drawing.PointF[] points = {
new System.Drawing.PointF(Location.X+Width/2, Location.Y),
new System.Drawing.PointF(Location.X+Width, Location.Y+Height),
new System.Drawing.PointF(Location.X, Location.Y+Height)
};
grfx.FillPolygon(new SolidBrush(Color.White), points);
grfx.DrawPolygon(new Pen(Color.Black, width: 4.0F), points);
grfx.DrawLine(Pens.Black, Rectangle.Left + (Rectangle.Right - Rectangle.Left) / 2, Rectangle.Top, Rectangle.Right + (Rectangle.Left - Rectangle.Right) / 2, Rectangle.Bottom);
grfx.DrawLine(Pens.Black, Rectangle.Left+103 , Rectangle.Top-32 + (Rectangle.Bottom - Rectangle.Top) / 2, Rectangle.Right , Rectangle.Bottom);
grfx.DrawLine(Pens.Black, Rectangle.Right-103, Rectangle.Top - 32 + (Rectangle.Bottom - Rectangle.Top) / 2, Rectangle.Left, Rectangle.Bottom);

Nadi G. 2-Jul-20 7:24am

i found a way but i do not know to to make trapezoid?

OriginalGriff 2-Jul-20 8:11am

Oh come on!
If you can draw a triangle, then a trapezoid is only one extra point!

            points = new PointF[] { new PointF(50, 50), new PointF(200, 200), new PointF(300, 200), new PointF(400, 50) };
            grfx.FillPolygon(new SolidBrush(Color.Blue), points);

Nadi G. 2-Jul-20 8:33am

Thank you for helping me!