Installing Dia On CentOS 7

Dia is a GTK+ based diagram creation program for Linux. It supports flowcharts, network diagrams, circuit diagrams, UML diagrams, and many other types. Here’s how to install and get started with Dia on CentOS 7.

Install Dia from EPEL

Dia is available in the EPEL (Extra Packages for Enterprise Linux) repository:

# Enable EPEL if not already enabled
sudo yum install epel-release

# Install Dia
sudo yum install dia

After installation, launch it from the application menu or run dia in a terminal.

Building Dia from Source

If the EPEL version is outdated or you need specific features, build from source:

# Install build dependencies
sudo yum groupinstall "Development Tools"
sudo yum install gtk2-devel libxml2-devel libxslt-devel gettext

# Download and build
wget https://ftp.gnome.org/pub/GNOME/sources/dia/0.97/dia-0.97.3.tar.xz
tar -xf dia-0.97.3.tar.xz
cd dia-0.97.3
./configure --enable-gnome
make
sudo make install

Common Diagram Types

Dia includes built-in shape libraries for many diagram types:

Flowchart — Process flows, decision trees, algorithm diagrams
UML — Class diagrams, sequence diagrams, use case diagrams
Network — Network topology, server racks, firewall layouts
Circuit — Electrical and logic circuits
Database — Entity-relationship diagrams
Sybase — Database schema diagrams
GRAFCET — Sequential function charts

Basic Usage

Creating a new diagram:

Launch Dia
Select a sheet (diagram type) from the left panel
Click a shape, then click on the canvas to place it
Use the toolbox to connect shapes with lines and arrows

Keyboard shortcuts:

Ctrl+N — New diagram
Ctrl+S — Save diagram
Ctrl+E — Export to another format
Ctrl+Z — Undo
Delete — Remove selected object
Ctrl+G — Group selected objects
Ctrl+Shift+G — Ungroup

Exporting Diagrams

Dia can export to many formats:

# From the GUI: File -> Export
# Or from the command line:
dia --export=output.png --filter=png input.dia
dia --export=output.pdf --filter=pdf input.dia
dia --export=output.svg --filter=svg input.dia

Supported export formats include PNG, SVG, PDF, EPS, PostScript, WMF, Shape, and LaTeX PGF. For high-quality print output, use SVG or PDF rather than PNG.

Custom Shapes

You can create custom shapes for Dia. A shape is defined in an XML file with a .shape extension:

~/.dia/shapes/my_custom.shape

Each shape file defines the geometry (SVG path), connection points, and text boxes. Place custom shapes in ~/.dia/shapes/ and they’ll appear in a new sheet in the toolbox.

Alternatives to Dia

While Dia is functional, there are more modern diagramming tools available:

draw.io (diagrams.net) — Web-based, free, excellent collaboration
LibreOffice Draw — Part of the LibreOffice suite, good for general diagrams
Inkscape — Vector graphics editor with diagramming capabilities
Mermaid — Text-based diagram generation (integrates with Markdown)
PlantUML — Text-based UML diagram generation

For quick network or flowchart diagrams, Dia remains a solid lightweight choice that doesn’t require an internet connection or modern web browser.

Batch Processing with Dia

Dia supports command-line batch export, useful for automated documentation pipelines:

# Export all .dia files in a directory to PNG
for f in *.dia; do
    dia --export="${f%.dia}.png" --filter=png "$f"
done

# Export to SVG for web publishing
dia --export=diagram.svg --filter=svg diagram.dia

# Export to EPS for LaTeX documents
dia --export=diagram.eps --filter=eps diagram.dia

Integrate with documentation builds:

# Makefile snippet for docs
diagrams: $(patsubst %.dia,%.png,$(wildcard images/*.dia))

%.png: %.dia
	dia --export=$@ --filter=png $<

Working with Dia Files Programmatically

Dia files are compressed XML. You can parse them directly:

# Decompress a .dia file
gunzip -c diagram.dia | xmllint --format - | less

# Extract all object types used
bunzip2 -c diagram.dia | grep 'type=' | sort -u

This makes Dia files suitable for version control (store the XML) and automated processing (count objects, validate diagram structure, generate reports).

Installing Dia on CentOS 7