Dia is a free, open-source diagram editor for Windows, macOS, and Linux that helps you create flowcharts, network diagrams, UML diagrams, and other structured graphics. Inspired by the commercial Visio application, Dia provides essential diagramming capabilities without cost.
The extensive shape library includes categories for flowcharts, UML, network diagrams, circuit diagrams, and more. Each category contains properly designed shapes with connection points. Custom shape sheets add specialized symbols for specific industries or needs.
Drawing tools include lines, polylines, curves, and basic shapes. Objects snap to grid and alignment guides for precise positioning. Connection points on shapes accept lines that stay connected when shapes move. Text labels attach to shapes and connections.
Layers organize complex diagrams with elements that can be shown or hidden individually. Z-ordering controls which objects appear in front. Grouping combines objects that work together. Object properties set colors, line styles, and other attributes.
Export formats include SVG, PNG, EPS, PDF, and more for various uses. The native .dia format saves edits non-destructively. Import from Visio VDX files enables working with existing diagrams.
Support for Python plugins extends functionality with custom shapes, file formats, and automation. The command-line interface enables batch processing. Print options handle multi-page diagrams with proper pagination. The interface adapts to different screen sizes and resolutions.