Applications in geographic information systems, electronic design automation, and complex visualization require a second level of graphics to display and manage arbitrary drawings such as maps, engineering diagrams, and images. Many successful programmers work only on form-based office automation tasks. However, Tk's canvas can help those with more general needs. Tk is the established basis for successful commercial GUI applications, many of which have stringent requirements for scale and performance. Geometry Tk's fans also laud the toolkit for its geometry management.
Geometry is the positioning of widgets on the visual screen.
Windows's Visual Basic is reputedly easy for beginners because of its IDE's facility for dragging and dropping widgets into a form. However, due to its inflexibility in managing windows of variable sizes, this approach is severely limited in building professional applications. Tk, by contrast, offers a variety of geometry managers, most of which can intelligently handle window resizing. This places three buttons in a sequence from left to right. Tk makes sure that the buttons are symmetrical and that they adjust properly to size changes.