Drawing a Custom Dashed Line

Windows GDI+ provides several dash styles that are listed in the DashStyle enumeration. If those standard dash styles don't suit your needs, you can create a custom dash pattern.

To draw a custom dashed line, put the lengths of the dashes and spaces in an array and pass the address of the array as an argument to the Pen::SetDashPattern method of a Pen object. The following example draws a custom dashed line based on the array {5, 2, 15, 4}. If you multiply the elements of the array by the pen width of 5, you get {25, 10, 75, 20}. The displayed dashes alternate in length between 25 and 75, and the spaces alternate in length between 10 and 20.

REAL dashValues[4] = {5, 2, 15, 4};
Pen blackPen(Color(255, 0, 0, 0), 5);
blackPen.SetDashPattern(dashValues, 4);
stat = graphics.DrawLine(&blackPen, Point(5, 5), Point(405, 5));

The following illustration shows the resulting dashed line. Note that the final dash has to be shorter than 25 units so that the line can end at (405, 5).