VARNA (Visualization Applet for RNA) is a Java lightweight component and applet for drawing the RNA secondary structure. Create RNA structures with this tool. It is also a Swing component that can be very easily included in an existing Java code working with RNA secondary structure to provide a fast and interactive visualization.

Being free of fancy external library dependency and/or network access, the VARNA Applet can be used as a base for a standalone applet. It looks reasonably good and scales up or down nicely to adapt to the space available on a web page, thanks to the anti-aliasing drawing primitives of Swing.

VARNA (Visualization Applet for RNA) Features:
1. Automatically scaled, anti-aliased smooth rendering
2. Support provided for input files in BPSEQ, CT, Vienna (DBN: dot bracket notation) or RNAML formats
3. Export of snapshots in vector and bitmap picture formats: EPS, SVG, XFIG, JPG, or PNG.
4. Fully-customizable, through a documented API for the component, or a set of documented "<param name="..." value="..." />"-type options for the Applet version
5. Platform and browser independence (Only requires the installation of a version 1.5 of the Java plugin
6. Support of non-canonical basepairs using the Leontis/Westhof nomenclature. Pseudoknotted structures are processed by first extracting a maximal planar subset of canonical base-pairs, draw the subset and use it as a scaffold for the rest of the base pairings.
7. Provides real time user interaction and full display customization.
8. Displays multiple secondary structures on a single Applet, saving precious computational ressources.
9. Supports semi-automated annotation of individual structural parts, color maps and chemical-probing style of annotations.
10. Open source, free-software distributed under the terms of the GNU GPL 3 license.

Requirements:
* Java

The license of this software is Free, you can free download and free use this calculator software.