# The wumpus-core package

[ Tags: bsd3, graphics, library ] [ Propose Tags ]

Wumpus - (W)riter (M)onad (P)ost (S)cript.

Wumpus is a kernel library for generating 2D vector pictures, its salient feature is portability due to no FFI dependencies. It can generate PostScript (EPS) files and SVG files. The generated PostScript code is plain [1] and reasonably efficient as the use of stack operations, i.e gsave and grestore, is minimized.

Pictures in Wumpus are made from paths and text labels. Paths themselves are made from points. The usual affine transformations (rotations, scaling, translations) can be applied to geometric objects. Unlike PostScript there is no notion of a current point, Wumpus builds pictures in a coordinate-free style.

GENERAL DRAWBACKS...

For actually drawing pictures, diagrams, etc. Wumpus is very low level. There is a supplemantary package wumpus-basic available that helps create certain types of diagram, but even this lacks the higher-level stuff (polygons, arrows etc.) that would make creating general drawings easy.

Some of the design decisions made for wumpus-core are not sophisticated (e.g. how attributes like colour are handled, and how the bounding boxes of text labels are calculated), so Wumpus might be limited compared to other systems. However, the design permits a fairly simple implementation - which is a priority. Text encoding an exception - I'm not sure how reasonable the design is. The current implementation appears okay for Latin 1 but may be inadequate for other character sets, so I may have to revise it significantly.

WARNING...

The module Core.BoundingBox is likely to be reworked significantly in the future. It has too many functions that do not offer distinct functionality. Some functions were removed in revision 0.17.0 and some more are likely to follow.

$1$ Because the output is simple, straight-line PostScript code, it is possible to use GraphicsMagick or a similar tool to convert Wumpus's EPS files to many other formats (bitmaps).

Changelog:

1. 22.0 TO 0.23.0:

• Basic.GraphicsState - extracted the font face fields from FontAttr datatype into a separate datatype FontFace.

• Added PtSize a numeric type wrapping Double. This is specifically for text size calculations, vis the Core.FontSize module.

• Changed all functions in Core.FontSize to return PtSize instead of a polymorphic type u (where u is an instance of Fractional). To get to another unit type rather than FontSize use an explicit conversion that scales the value accordingly.

• Added FromPtSize class constraints to various functions in Core.Picture.