giv, short from G(reat|tk|NU) Image Viewer, is an open source, cross-platform and freely distributed graphical application designed to provide a vector image viewer, an 8-bit to 32-bit image viewer, as well as a floating point image viewer.

Key features include support for multi-slice images, the ability to measure distance in images, hierarchical layering of data sets, support for exporting and printing images to the PostScript, SVG, PDF and PNG file formats, pseudo coloring of images with gray levels, an interactive contrast utility, support for reading DICOM, FITS-format and npy-format images, Anti-Grain Geometry functionality for accurate and fast on-screen drawing, as well as a powerful plugin architecture.

The software has been specifically engineered to be used for computational geometry and scientific vision areas. It also allows users to easily draw vector graphics on top of any image. The giv project is comprised of three tools, giv, gtk-image-viewer and gxgraph.

While the giv component is the main hierarchical vector and image viewer, which can also be used for drawing vector graphics on top of a given image, the gtk-image-viewer component has been designed from the offset to act as an image display widget, which can handle image panning and zoom.

Lastly, the gxgraph component of the giv project is a line data plotter tool derived from the xgraph program, but ported to the GTK+ toolkit and greatly improved with new functionality, such as support for reading the giv file format syntax.

giv is written entirely in the C and C++ programming languages, using the GTK+ GUI toolkit for its graphical user interface. At the moment, it supports GNU/Linux, FreeBSD and Microsoft Windows operating systems.

It is available for download for free on Softpedia, as well as on its official website, as a universal sources archive, allowing the user to optimize the application for his/her operating system and hardware platform (32-bit and 64-bit architectures are supported).