Based on PythonQwt (a pure Python/PyQt reimplementation of the curve plotting Qwt C++ library, included in guiqwt base source code) and on the scientific modules NumPy and SciPy, guiqwt is a Python library providing efficient 2D data-plotting features (curve/image visualization and related tools) for interactive computing and signal/image processing application development. It is based on Qt graphical user interfaces library, and currently supports both PyQt4 and PyQt5.