System.Drawing.Drawing2D Namespace in C#

The System.Drawing.Drawing2D namespace provides advanced two-dimensional and vector graphics functionality. The following table lists some of the important classes in theSystem.Drawing.Drawing2D namespace, and their descriptions.

CLASS	DESCRIPTION
PathGradientBrush	Encapsulates a Brush object that fills the interior of a GraphicsPath object with a gradient. This class cannot be inherited.
LinearGradientBrush	Encapsulates a Brush with a linear gradient. This class cannot be inherited.
ColorBlend	Defines arrays of colors and positions used for interpolating color blending in a multicolor gradient. This class cannot be inherited.
GraphicsPath	Represents a series of connected lines and curves. This class cannot be inherited.
HatchBrush	Defines a rectangular brush with a hatch style, a foreground color, and a background color. This class cannot be inherited.
Blend	Defines a blend pattern for a LinearGradientBrush object. This class cannot be inherited.
PathData	Contains the graphical data that makes up a GraphicsPath object. This class cannot be inherited.

In the following example the System.Drawing.Drawing2D namespace is implemented, with which a star with different effects like rotation and change of color with the aid of timer is drawn.

First we are going to implement the System .Drawing.Drawing2D namespace.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D; <-//this is the necessary namespace
using System.Threading;

Then, we are going to declare the variables that are going to be used in the program.

double a = 0.0;
double angle;
Random ram = new Random();//this object is going to be used to the color
bool alto = false;

In the Form's event resize we are going to use the method Invalidate(), this method invalidates the entire surface of the control and causes the control to be redrawn.

private void Form1_Resize(object sender, EventArgs e)
{
  Invalidate();
  this.Refresh();
}

Inside of timer´s event we will implement the code of the picture,we will use the Point structure,this represents an x- and y-coordinate pair in two-dimensional space, and we can found the color and the angle for the figure´s rotation too.

private void timer1_Tick(object sender, EventArgs e)
{
    Point[] apt = new Point[5];
    for (int i = 0; i < apt.Length; i++)
    {           
      angle = ((i * 0.8 - 0.5) * Math.PI) + a;
      apt[i] = new Point((int)(ClientSize.Width * (.5 + .48 *   Math.Cos(angle))), (int)(ClientSize.Height * (.5 + .48 * Math.Sin(angle))));
    }
PathGradientBrush brocha = new PathGradientBrush(apt);
brocha.CenterColor = Color.Chocolate;
brocha.SurroundColors = new Color[5] { Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)), Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)), Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)), Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)), Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)) };

Graphics g = this.CreateGraphics();
// RECTANGLE WITH FILLER DEGRADED
Rectangle rect = new Rectangle(0, 0, ClientSize.Width, ClientSize.Height);
LinearGradientBrush lBrush = new LinearGradientBrush(rect, Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)), Color.FromArgb(ram.Next(256), ram.Next(256), ram.Next(256)), LinearGradientMode.Vertical);
g.FillRectangle(lBrush, rect);
g.FillRectangle(brocha, 0, 0, ClientSize.Width, ClientSize.Height);
Thread.Sleep(200);
 a += 45;
}

And finally, the button's code to enable and disable the timer.

private void button1_Click(object sender, EventArgs e)
        {
            if (alto == false)
            {
                timer1.Enabled = true;
                alto = true;
            }
            else
            {
                alto = false;
                timer1.Enabled = false;
            }
        }