Bézier Curve

Bézier Curves are used for smoothed line and polygons inside the Canvas; as TkPath path segments; as TkZinc 3.3.4 curve segments.

Bézier Curves are characterised by knots and control points. The Bézier control points are off the resulting curve.


Dots Per Inch

Resolution measurement for printers.



A monochrome vector graphic symbol. Usually constructed from splines or bezier-curves.

Glyphs are the character definitions inside a font.


Lagrande Curves

Interpolating Splines.

The control points of a Lagrande Curve are aligned on the resulting curve.

See also: Spiro, Hermite, B-Splines, NURBS and clothoid.


Pixel Per Inch

Resolution measurements for Displays.


Scalable Vector Graphics

2D Vector Graphics Drawing System based on a XML-Schemata.

SVG is rather a visualization system than a vector graphics drawing system. It features: filters, animations, hierarchies, transformations and viewports.


General term denoting approximating curves such as Bézier curves and interpolating curves such as Lagrande.

In »tclsplines« and Tk Canvas a two way interpolation and approximation approach is being used to smooth lines. First a interpolated curve is calculated with n predefined steps. The interpolated points are then smoothed using Bézier curve segments.

The Tk Documentation terms this »parabolic splines«. Most likely B-Splines.

Visit the following web sites on splines: Wikipedia,,, and


Tool Command Language

Pronounced »tickel«.

Tcl is a simplistic, yet powerful language, which features list and strings as data types.


Widely used Graphical User Interface Toolkit. Originally fashioned after the Motif Toolkit under X Window System.

Tk can be used with: Lisp, Ruby, Python, Perl, C, Tcl, Erlang, Limbo, Ada, Cobol...

Tk is the Graphical User Interface of the Inferno Operating System.



A predominantly rectangular shape inside a Graphical User Interface. In general actions or event handlers are associated with it.

»button«, is an example for a window. The class is »Button« and each instance of a button may have a »-command« attribute.


See Window.