Diagrams make it easier to an understand complex issues. Creating such graphics using LibreOffice Draw or Gimp can quickly test your patience, as these programs offer an extremely large number of functions, which requires a massive learning curve.

For the occasional diagram, what you really need is an easier-to-use solution that gives usable results fast. With Dia Diagram Editor [1], professional-looking graphics and diagrams can be designed quickly with hardly any training.

Installation

Dia, which is based on the GTK+ toolkit, can be found in popular Linux distribution's repositories and set up with the respective package manager. You will typically get the latest available version since the current version, Dia v0.97, dates back to 2013. You can also find other (including older) versions on SourceForge, including various BSD derivatives, macOS, and Windows. Once installed, you will find Dia in the Applications section of your desktop's main menu.

Getting Started

When you launch Dia, a clear-cut program window opens. On the left, you will find a toolbar with numerous graphical elements that can be integrated into the diagrams. At the top below the menubar, a buttonbar allows quick access to important functions. The workspace, or canvas in Dia parlance, on the right is divided into a grid of boxes that allows precise positioning of graphic elements.

You can start using Dia without any further configuration. To create your first diagram element, use the object icons located in the lower half of toolbar on the left. If you don't see the object you need, click on the selection field in the middle of the toolbar. From the context menu that opens, select Other sheets to access additional object collections from a wide variety of disciplines (Figure 1), such as civil engineering, chemical engineering, electrical engineering, electronics, IT, lighting, hydraulics, and circuits.

Figure 1: Dia offers additional graphical elements for multiple disciplines.

To create a diagram, drag the desired object from the object collection to the canvas. The object will now have small green square handles at each corner and in the center of each side. You can change the size and aspect ratio of an object by clicking on a handle and then dragging it while holding down the left mouse button. You can reposition the object by clicking inside the object, holding down the left mouse button, and dragging the entire object to the desired location.

If you've placed several objects on the canvas, you can connect them with lines or geometric shapes using the drawing tools located at the top of the toolbar on the left. Click the desired tool and then click on the starting point for your line (or shape). While holding down the left mouse button, drag the mouse to the endpoint, and the corresponding line or geometric shape will now appear on the canvas. In this way, you can also integrate freehand symbols into the diagram and connect the individual objects with lines.

Additional Libraries

If you can't find the object you need, you can extend Dia with additional object collections with a separate repository that offers still more object collections [2].

You can integrate these collections into your existing application using the Diashapes tool. You can download the Diashapes tool for 32- and 64-bit systems from the project's website [3]. After installing the tool, integrate the additional libraries into your Dia installation (Figure 2).

Figure 2: The Diashapes tool lets you extend your Dia object toolbox.