MetaPost

MetaPost
MetaPost
MPlogo.svg
Paradigm(s) imperative, typesetting
Appeared in 1994 (1994)
Designed by John D. Hobby
Developer Taco Hoekwater
Stable release 1.211 (1 April 2010; 18 months ago (2010-04-01))
Preview release 1.502 (27 July 2010; 15 months ago (2010-07-27))
Typing discipline duck, dynamic, strong
Influenced by Metafont
OS Cross-platform
License Public domain
Website Development website

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 excels at producing diagrams in the PostScript programming language from a geometric/algebraic description. The language shares Metafont's elegant 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 a simple RGB colour specification.
  • The MetaPost language can include text labels on the diagrams, either strings from a specified font, or pretty much anything that can be typeset with TeX
  • The Metafont interpreter was written by Donald Knuth under an open source license, allowing John D. Hobby to adapt the interpreter to his own ends, giving us MetaPost.

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.

Contents

Availability, usage

MetaPost is distributed with many current distributions of the TeX and Metafont framework. In particular, it is included in the teTeX and the TeX Live distribution, common on Linux and Unix (including Mac OS X) platforms.

The encapsulated postscript produced by Metapost is easily included in TeX, ConTeXt, and LaTeX documents via standard eps-inclusion commands. Particularly useful is the ability to include this output in the PDFTeX dialect of TeX, thus giving Portable Document Format output from TeX in a single step. This ability is implemented in ConTeXt and in the LaTeX graphics package, and can be used from plain TeX via the supp-pdf.tex macro file. ConTeXt even supports the creation of MetaPost files from within the TeX file.

Although MetaPost itself cannot generate fonts, there is another program, METATYPE1, that is designed to create Type1 fonts through MetaPost.

Examples

This is a single file example.mp which when processed by the MetaPost interpreter (via the command mpost on Linux) produces three eps files example.1, example.2, example.3. These are pictured on the right.

Metapost ex.svg
transform pagecoords;
pagecoords:=identity scaled 10mm shifted (100mm,150mm);
beginfig (1)
    fill ((0,0)--(2,0)--(2,1)--(1,1)--(1,2)--(0,2)--cycle)
        transformed pagecoords withcolor green;
    draw ((2,0)..(2,1)..(1,1)..(1,2)..(0,2))
        transformed pagecoords;
    drawarrow ((0,0)--(2,2)) transformed pagecoords;
endfig;
beginfig (2)
    draw (for i=0 upto 7: dir (135i)-- endfor cycle)
        transformed pagecoords;
endfig;
pagecoords:=identity scaled 15mm shifted (100mm,150mm);
beginfig (3);
    % declare paths to be used
    path p[],p[]t;
    % set up points by defining relationships
    z1=(0,0);   z2=z1+2up;
    z3=z1+whatever*dir (60)=z2+whatever*dir (-50);
    z4=z3+(-1.5,-.5);
    z5=z1+dir (135);
    z0=whatever[z1,z2]=whatever[z3,z4];
    % set up paths
    p0=fullcircle yscaled .5 rotated 45 shifted z0 ;
    p1=z2---z4..z0..z3---z1;
    p2=p1 cutbefore p0 cutafter p0;
    p3=p0 cutbefore p1 cutafter p1;
    p4=p2---p3---cycle;
    % define transformed versions of paths and points
    for i=0 upto 4: p[i]t=p[i] transformed pagecoords; endfor
    for i=0 upto 5: z[i]t=z[i] transformed pagecoords; endfor
    % do some drawing
    fill p4t withcolor (1,1,0.2);
    draw z1t---z2t withcolor .5white;
    draw z3t---z4t withcolor .5white;
    pickup pencircle;
    draw p0t dashed withdots scaled .3;
    draw p1t dashed evenly;
    draw p2t withcolor blue;
    draw p3t withcolor red;
    label.lrt (btex $z_0$ etex, z0t);
    label.llft (btex $z_1$ etex, z1t);
    label.top (btex $z_2$ etex, z2t);
    label.rt (btex $z_3$ etex, z3t);
    label.llft (btex $z_4$ etex, z4t);
    for i=0 upto 4:
        drawdot z[i]t withpen pencircle scaled 2;
    endfor
endfig;
bye

The resulting three eps files can be used in TeX via LaTeX's \includegraphics command, ConTeXt's \externalfigure, Plain TeX's \epsfbox command, or (in Plain pdftex) the \convertMPtoPDF command from supp-pdf.tex. To view or print the third diagram, this inclusion is necessary, as the TeX font (Metafont) is not included in the eps files produced by MetaPost.

See also

References

External links


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • MetaPost — Класс языка: императивный Появился в …   Википедия

  • Metapost — est un système qui implante un langage de construction de figures et est interpréteur de ce langage. MetaPost dérive du système Metafont du docteur Donald Knuth. MetaPost est spécialisé dans la production de diagrammes en langage PostScript à… …   Wikipédia en Français

  • MetaPost — Desarrollador Taco Hoekwater (Autor: John D. Hobby) foundry.supelec.fr/projects/metapost/ …   Wikipedia Español

  • Metapost — Maintainer: Taco Hoekwater Entwickler: John D. Hobby Aktuelle Version: 1.001 …   Deutsch Wikipedia

  • MetaPost — est un système qui implémente un langage de construction de figures et est interpréteur de ce langage. Il dérive du système Metafont du docteur Donald Knuth, et est spécialisé dans la production de diagrammes en langage PostScript à partir d une… …   Wikipédia en Français

  • MetaPost — Maintainer Taco Hoekwater Entwickler John D. Hobby Aktuelle Version 1.211 …   Deutsch Wikipedia

  • Metapost — …   Википедия

  • Metafont — Developer(s) Donald Knuth Stable release 2.718281 / March 2008 Operating syste …   Wikipedia

  • Metafont — Entwickler: Donald Knuth Aktuelle Version: 2.718281 (März 2008) …   Deutsch Wikipedia

  • ConTeXt — Not to be confused with ConTEXT. ConTeXt Original author(s) Mainly Hans Hagen and Pragma ADE …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”