It’s very easy to create Dotted, Dashed and other types of lines in Gimp. Let’s look at how to achieve these effects. This technique uses Brushes to create different types of lines
1. Create a New Document. Click on File > New (Cmd + N)
2. Select the Paintbrush Tool. (shortcut P)
3. In the Tool options select a round brush and change the size of the brush to 10px. Select Black color which would be the default color or any color of your choice.
4. Now we need to change the spacing option in the Brushes panel. Go to Windows > Dockable Dialogs > Brushes (Shift + Cmd + B). Change the spacing to 200.
5. Click anywhere on the document. Press Shift (to create a straight line) and click on another point in the document. You would get a straight dotted line as shown below.
6. You can also create dashed lines. Just change the brush type to a line. Similarly you can create other types of lines.
7. You can also stroke selections as shown below. Make a selection. Click Edit > Stroke Selection. Select Stroke with a paint tool and under options select Paintbrush. Click Stroke.
8. You will get a stroke in your selections as shown below.