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Introduction
GDI+ has made the windows graphics programming really easy. You can easily draw
and control the graphical interface of you application. This section will explain
how can you draw pattern lines in GDI+.
To do anything in GDI+, you always need the object of Graphics class. Most of the
GDI+ related code in called in Paint event of ant windows controls. You can attach
handler of this event.
this.Paint += new PaintEventHandler(this_Paint);
private void this_Paint(object sender, PaintEventArgs e)
{
// drawing code here.
}
A simple line could be drawn using Graphics.DrawLine function, however you need
object on Pen to draw a line.
Pen pen = new Pen(Color.Green, 2.0F);
e.Graphics.DrawRectangle(pen, 10, 10, 200, 100);
e.Graphics.DrawLine(pen, 20, 20, 200, 20);
e.Graphics.DrawLine(pen, 20, 30, 200, 30);
e.Graphics.DrawLine(pen, 20, 40, 200, 40);
pen.Dispose();
Patterned lines
You can externally specify the pattern of the line using Pen.DashStyle. There are
some build in patterns available in .net. (Dash, Dot, DashDot, DashDotDot)
Pen pen = new Pen(Color.Black, 2.0F);
pen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
e.Graphics.DrawRectangle(pen, 10, 10, 200, 100);
e.Graphics.DrawLine(pen, 20, 20, 200, 20);
e.Graphics.DrawLine(pen, 20, 30, 200, 30);
e.Graphics.DrawLine(pen, 20, 40, 200, 40);
pen.Dispose();
Setting Custom Patterns
If you want to create you own custom pattern of the line, then you can use the Pen.DashPattern
to set you own custom pattern.
Pen pen = new Pen(Color.Black, 2.0F);
pen.DashPattern = new float[] { 4, 2, 13, 4, 2, 3 };
e.Graphics.DrawRectangle(pen, 10, 10, 200, 100);
e.Graphics.DrawLine(pen, 20, 20, 200, 20);
e.Graphics.DrawLine(pen, 20, 30, 200, 30);
e.Graphics.DrawLine(pen, 20, 40, 200, 40);
pen.Dispose();
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