What is "metapost"

MetaPost refers to both a programming language and the interpreter of the MetaPost programming language. Both are derived from Donald Knuth's Metafont language and interpreter. MetaPost produces diagrams in the PostScript programming language from a geometric/algebraic description. The language shares Metafont's declarative syntax for manipulating lines, curves, points and geometric transformations. However,

• Metafont is set up to produce fonts, in the form of image files (in .gf format) with associated font metric files (in .tfm format), whereas MetaPost produces encapsulated PostScript files
• The output of Metafont consists of the fonts at a fixed resolution in a raster-based format, whereas MetaPost's output is vector-based postscript graphics (lines, Bézier curves)
• Metafont output is monochrome, whereas MetaPost uses RGB colors.
• The MetaPost language can include text labels on the diagrams, either strings from a specified font, or anything else that can be typeset with TeX.

Many of the limitations of MetaPost derive from features of Metafont. For instance, numbers have a low-precision fixed-point representation, sufficient for representing the coordinates of points in a glyph, but this can be restrictive when working with figures in a larger coordinate space. Moreover, MetaPost does not support all features of PostScript. Most notably, paths can have only one segment (so that regions are simply connected), and regions can be filled only with uniform colours. PostScript level 1 supports tiled patterns and PostScript 3 supports Gouraud shading. To this end, the Asymptote graphics language has been developed to address these shortcomings.