# The wumpus-core package

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

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

Wumpus is a 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 quite efficient (no unnecessary stack operations).

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. There is a set of combinators for composing pictures (more-or-less similar to the usual pretty printing combinators).

With revision 0.15.0 I've added three extra helper modules that are not really part of the "core", but they provide lists of named colours and fonts.

WARNING...

wumpus-core is likely to change quite a bit with the next revision as I want to see if I can make Primitives support affine translations. Hopefully this will not change the API significantly though it will mean the generated SVG and PostScript files will be different (possibly clearer). Also the Core.BoundingBox module is not too well designed, too many functions that do not offer distinct functionality. Some functionality was removed in this revision (0.17.0) and more is likely to follow.

GENERAL DRAWBACKS...

For actually drawing pictures, diagrams, etc. Wumpus is very low level. I've worked on a complementary package wumpus-extra with higher-level stuff (polygons, arrows etc.) but it is too unstable for Hackage. Preview releases can be found at http://code.google.com/p/copperbox/ though.

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 its design permits a 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 I'm not sure about other character sets, and I may have to revise it significantly.

With revision 0.14.0, I've added the first draft of a user guide. Source for the guide is included as well as the PDF as there is an extra example picture. wumpus-extra hasn't received any more attention unfortunately, so Wumpus is still really a bit too primitive for general use. However, if you want FFI-free vector graphics and Wumpus seems to otherwise fit the task, please email me and I will try to help.

$1$ 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. 16.0 to 0.17.0:

• Added Core.WumpusTypes to export opaque versions of datatypes from Core.PictureInternal. This should make the Haddock documentation more cohesive.

• Moved the Core.PictureLanguage module into the Extra namespace (Extra.PictureLanguage). This module change in detail, if not in spirit in the future as I'm not to happy with it. Also this model is somewhat "higher-level" than the modules in wumpus-core, so a different home seems fitting.

• Removed CardinalPoint and boundaryPoint from BoundingBox.

• Argument order of textlabel and ztextlabel changed so that Point2 is the last argument.

• PathSegment constructor names changed - this is an internal change as the constructors are not exported.

• Primitive type changed - moved Ellipse properties into PrimEllipse type - internal change.

• Removed dependency on 'old-time'.

1. 15.0 to 0.16.0:

• Additions to Core.Geometry (direction, pvec, vangle, circularModulo).

• Fixed error with langle due to not accounting for circle quadrants in Core.Geometry.

• Point2 now derives Ord - so it can be used as a key for Data.Map.

• Added escape-character handling to text output in PostScript. This was causing a nasty bug where a drawing would completely fail when special chars shown (GhostView gives little hint of what is wrong when such errors are present).

• Changed BoundingBox operation corners to return a 4-tuple rather than a list.