This article has been
excerpted from book "Graphics Programming with GDI+".
We create a Windows application and a MainMenu control with three menu items on
the form. We call these menu items GetCapStyle, LineDashStyle, and LineDashCap,
respectively, and write menu click event handlers by double-clicking on them. On
the GetCapStyle menu item click event handler, we will read different line caps
and generate output using these line caps; on the LineDashStyle menu item click
event handler, we will generate lines with different dash styles; and on the
LineDashCap menu item click event handler, we will generate output with
different line dash caps.
The GetCapStyle menu item click event handler is shown in Listing 9.2. We create
a pen and set the starting and ending caps using the StartCap and EndCap
properties of the Pen Object, and then we draw a line.
LISTING 9.2: Getting line caps
using System;
using
System.Collections.Generic;
using
System.ComponentModel;
using System.Data;
using
System.Drawing;
using
System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using
System.Windows.Forms;
namespace
GettingSetting_Line_CapsStyles
{
public partial class Form1 :
Form
{
public Form1()
{
InitializeComponent();
}
private void
Form1_Paint(object sender,
PaintEventArgs e)
{
Graphics g =
this.CreateGraphics();
g.Clear(this.BackColor);
// Create a pen
Pen blackPen =
new Pen(Color.Black,
10);
// Set line styles
blackPen.StartCap = LineCap.Triangle;
blackPen.EndCap = LineCap.Triangle;
g.DrawLine(blackPen, 20, 10, 200, 10);
blackPen.StartCap = LineCap.Square;
blackPen.EndCap = LineCap.AnchorMask;
g.DrawLine(blackPen, 20, 50, 200, 50);
blackPen.StartCap = LineCap.DiamondAnchor;
blackPen.EndCap = LineCap.DiamondAnchor;
g.DrawLine(blackPen, 20, 70, 200, 70);
blackPen.StartCap = LineCap.Flat;
blackPen.EndCap = LineCap.Flat;
g.DrawLine(blackPen, 20, 110, 200, 110);
blackPen.StartCap = LineCap.RoundAnchor;
blackPen.EndCap = LineCap.RoundAnchor;
g.DrawLine(blackPen, 20, 130, 200, 130);
blackPen.StartCap = LineCap.Square;
blackPen.EndCap = LineCap.Square;
g.DrawLine(blackPen, 20, 150, 200, 150);
blackPen.StartCap = LineCap.SquareAnchor;
blackPen.EndCap = LineCap.SquareAnchor;
g.DrawLine(blackPen, 20, 170, 200, 170);
blackPen.StartCap = LineCap.Flat;
blackPen.EndCap = LineCap.Flat;
g.DrawLine(blackPen, 20, 190, 200, 190);
// Dispose of objects
blackPen.Dispose();
g.Dispose();
}
}
}
The output of Listing 9.2 looks like Figure 9.4, in which the lines have
different caps.
The LineDashStyle menu item click event handler code is given in Listing 9.3. We
create a pen and set the dash style and dash offset values using the DashStyle
and DashOffset properties of the Pen object, and then we draw lines.
FIGURE 9.4: Reading line caps
LISTING 9.3: Getting line dash styles
using System;
using
System.Collections.Generic;
using
System.ComponentModel;
using System.Data;
using
System.Drawing;
using
System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using
System.Windows.Forms;
namespace
GettingSetting_Line_CapsStyles
{
public partial class Form1 :
Form
{
public Form1()
{
InitializeComponent();
}
private void
Form1_Paint(object sender,
PaintEventArgs e)
{
Graphics g =
this.CreateGraphics();
g.Clear(this.BackColor);
// Create a pen
Pen blackPen =
new Pen(Color.Black,
6);
// Set line styles
blackPen.DashStyle = DashStyle.Dash;
blackPen.DashOffset = 40;
blackPen.DashCap = DashCap.Triangle;
g.DrawLine(blackPen, 20, 10, 500, 10);
blackPen.DashStyle = DashStyle.DashDot;
g.DrawLine(blackPen, 20, 30, 500, 30);
blackPen.DashStyle = DashStyle.DashDotDot;
g.DrawLine(blackPen, 20, 50, 500, 50);
blackPen.DashStyle = DashStyle.Dot;
g.DrawLine(blackPen, 20, 70, 500, 70);
blackPen.DashStyle = DashStyle.Solid;
g.DrawLine(blackPen, 20, 70, 500, 70);
// Dispose of objects
blackPen.Dispose();
g.Dispose();
}
}
}
FIGURE 9.5: Reading line dash styles
Figure 9.5 shows the output from Listing 9.3. The lines have different dash
styles.
The GetCapStyle menu item click event handler code is given in Listing 9.4. We
create a pen and set the dash cap styles using the DashCap property of the Pen
object.
LISTING 9.4: Getting dash caps
using System;
using
System.Collections.Generic;
using
System.ComponentModel;
using System.Data;
using
System.Drawing;
using
System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using
System.Windows.Forms;
namespace
GettingSetting_Line_CapsStyles
{
public partial class Form1 :
Form
{
public Form1()
{
InitializeComponent();
}
private void
Form1_Paint(object sender,
PaintEventArgs e)
{
Graphics g =
this.CreateGraphics();
g.Clear(this.BackColor);
// Create a pen
Pen blackPen =
new Pen(Color.Black,
10);
// Set DashCap styles
blackPen.DashStyle = DashStyle.DashDotDot;
blackPen.DashPattern = new float[] { 10 };
blackPen.DashCap = DashCap.Triangle;
g.DrawLine(blackPen, 20, 10, 500, 10);
blackPen.DashCap = DashCap.Flat;
g.DrawLine(blackPen, 20, 30, 500, 30);
blackPen.DashCap = DashCap.Round;
g.DrawLine(blackPen, 20, 50, 500, 50);
// Dispose of objects
blackPen.Dispose();
}
}
}
Figure 9.6 shows the output from Listing 9.4. The lines have different dash
caps: triangular, flat, and round, respectively.
FIGURE 9.6: Getting line dash caps
Conclusion
Hope the article would have helped you in understanding Getting and Setting Line
Caps and Styles in GDI+. Read other articles on GDI+ on the website.
| This book teaches
.NET developers how to work with GDI+ as they develop applications
that include graphics, or that interact with monitors or printers.
It begins by explaining the difference between GDI and GDI+, and
covering the basic concepts of graphics programming in Windows. |