how can i draw circle

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1.00/5 (1 vote)

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how can i draw a circle in c# windows form( half colored and half not)
i know how draw circle but i cant color it
i hope you understand me
and this how i draw circle

C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.DrawEllipse(Pens.Red, 50, 50, 100, 100);
        }
    }
}

is that right or not

Posted 1-Nov-11 1:04am

rawa1990

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Comments

Mehdi Gholam 1-Nov-11 7:06am

Have you tested it?

3 solutions

Solution 3

Bob's answer is correct. See some more important details below:

All you need is System.Drawing.Graphics.FillPie(Brush, Rectangle) before of DrawEllipse, see http://msdn.microsoft.com/en-us/library/dw5wshbd.aspx[^].

If you want to allocate a brush, don't dispose it manually as UJimbo advised. That code is wrong because it will leak memory/resources in the case of exceptions. The right approach is using using statement:

C#

Rectangle ellipseBounds = new Rectangle(50, 50, 100, 100); //like in your code sample
using (Brush brush = new SolidBrush(/* some parameters */)) {
    e.Graphics.FillPie(brush, ellipseBounds, 0, 180); //for example, do it before drawing lines.
    e.Graphics.DrawEllipse(Color.Red, ellipseBounds);
} //brush.Dispose will be automatically called here, even if exception is thrown

Same thing about allocation of pens, etc.

—SA

Posted 11-Dec-11 13:09pm

Sergey Alexandrovich Kryukov

Updated 11-Dec-11 15:56pm

v4

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BobJanova · Accepted Answer · 2011-11-01T01:17:00

Solution 1

If you want it half 'coloured' (you mean filled in right?) and half not, it's not a circle. It's two arcs. Use Graphics.DrawArc[^] and FillPie.

(Edit: Whose idea was it to call the Fill and Draw items different things ...)

Posted 1-Nov-11 1:17am

BobJanova

Updated 1-Nov-11 1:55am

v2

Comments

rawa1990 1-Nov-11 8:36am

thanks for the idea

Sergey Alexandrovich Kryukov 11-Dec-11 19:16pm

Agree, my 5.
I added some detail and credited this correct answer in my solution.
--SA

UJimbo · Accepted Answer · 2011-11-01T01:28:00

You can thank BobJanova for that, DrawArc was a good hint.

System.Drawing.SolidBrush brush0 = new System.Drawing.SolidBrush(System.Drawing.Color.Black);
System.Drawing.SolidBrush brush1 = new System.Drawing.SolidBrush(System.Drawing.Color.Red);
System.Drawing.SolidBrush brush2 = new System.Drawing.SolidBrush(System.Drawing.Color.Blue);

System.Drawing.Pen thePen = new System.Drawing.Pen(brush0);
System.Drawing.Graphics formGraphics = this.CreateGraphics();

formGraphics.DrawArc(thePen, new System.Drawing.Rectangle(150, 50, 100, 100), 0, 180);
formGraphics.DrawArc(thePen, new System.Drawing.Rectangle(150, 50, 100, 100), 180, 360);
formGraphics.FillPie(brush1, new System.Drawing.Rectangle(150, 50, 100, 100), 0, 180);
formGraphics.FillPie(brush2, new System.Drawing.Rectangle(150, 50, 100, 100), 180, 180);

brush0.Dispose();
brush1.Dispose();
brush2.Dispose();
thePen.Dispose();
formGraphics.Dispose();