.. _glossary: ******** Glossary ******** .. glossary:: AGG The Anti-Grain Geometry (`Agg `_) rendering engine, capable of rendering high-quality images Cairo The `Cairo graphics `_ engine dateutil The `dateutil `_ library provides extensions to the standard datetime module EPS Encapsulated Postscript (`EPS `_) freetype `freetype `_ is a font rasterization library used by matplotlib which supports TrueType, Type 1, and OpenType fonts. GDK The Gimp Drawing Kit for GTK+ GTK The GIMP Toolkit (`GTK `_) graphical user interface library JPG The Joint Photographic Experts Group (`JPEG `_) compression method and file format for photographic images numpy `numpy `_ is the standard numerical array library for python, the successor to Numeric and numarray. numpy provides fast operations for homogeneous data sets and common mathematical operations like correlations, standard deviation, fourier transforms, and convolutions. PDF Adobe's Portable Document Format (`PDF `_) PNG Portable Network Graphics (`PNG `_), a raster graphics format that employs lossless data compression which is more suitable for line art than the lossy jpg format. Unlike the gif format, png is not encumbered by requirements for a patent license. PS Postscript (`PS `_) is a vector graphics ASCII text language widely used in printers and publishing. Postscript was developed by adobe systems and is starting to show its age: for example is does not have an alpha channel. PDF was designed in part as a next-generation document format to replace postscript pygtk `pygtk `_ provides python wrappers for the :term:`GTK` widgets library for use with the GTK or GTKAgg backend. Widely used on linux, and is often packages as 'python-gtk2' pyqt `pyqt `_ provides python wrappers for the :term:`Qt` widgets library and is required by the matplotlib QtAgg and Qt4Agg backends. Widely used on linux and windows; many linux distributions package this as 'python-qt3' or 'python-qt4'. python `python `_ is an object oriented interpreted language widely used for scripting, application development, web application servers, scientific computing and more. pytz `pytz `_ provides the Olson tz database in Python. it allows accurate and cross platform timezone calculations and solves the issue of ambiguous times at the end of daylight savings Qt `Qt `__ is a cross-platform application framework for desktop and embedded development. Qt4 `Qt4 `__ is the most recent version of Qt cross-platform application framework for desktop and embedded development. raster graphics `Raster graphics `_, or bitmaps, represent an image as an array of pixels which is resolution dependent. Raster graphics are generally most practical for photo-realistic images, but do not scale easily without loss of quality. SVG The Scalable Vector Graphics format (`SVG `_). An XML based vector graphics format supported by many web browsers. TIFF Tagged Image File Format (`TIFF `_) is a file format for storing images, including photographs and line art. Tk `Tk `_ is a graphical user interface for Tcl and many other dynamic languages. It can produce rich, native applications that run unchanged across Windows, Mac OS X, Linux and more. vector graphics `vector graphics `_ use geometrical primitives based upon mathematical equations to represent images in computer graphics. Primitives can include points, lines, curves, and shapes or polygons. Vector graphics are scalable, which means that they can be resized without suffering from issues related to inherent resolution like are seen in raster graphics. Vector graphics are generally most practical for typesetting and graphic design applications. wxpython `wxpython `_ provides python wrappers for the :term:`wxWidgets` library for use with the WX and WXAgg backends. Widely used on linux, OS-X and windows, it is often packaged by linux distributions as 'python-wxgtk' wxWidgets `WX `_ is cross-platform GUI and tools library for GTK, MS Windows, and MacOS. It uses native widgets for each operating system, so applications will have the look-and-feel that users on that operating system expect.