wumpus-core: Pure Haskell PostScript and SVG generation.

Wumpus is a low-level library for generating static 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.

Wumpus makes pictures from paths and text labels. Paths themselves are made from points. The usual affine transformations (rotations, scaling, translations) can be applied to Pictures. 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 it is experimental - functionality is added and dropped between releases, it has no stable API.

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.

NOTE version 0.37.0 - there will be no release of Wumpus-Basic to match this release of Wumpus-Core. Wumpus-Basic is undergoing substantial change to accommodate glyph metrics and thus enable proper text bounding boxes and right and center aligned text. The improvements to Wumpus-Core merit a release so that there is not a large hiatus between the APIs of the Hackage published latest version and the SVN repository.

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

Changelog:

1. 36.0 to 0.37.0:

• The bounding box constructors have been renamed - bbox is now boundingBox and obbox becomes oboundingBox. The rationale for this change is that the names very cryptic in the first place and the constructors are used infrequently when bbox in particular makes a descriptive variable name.

• Changes to the Picture and Primitive types to enable better concatenation which is used heavily by Wumpus-Basic. The Picture API exposes a new function primCat.

• SVG font delta context change - font deltas are now annotated on Primitives not Pictures. The type of the function fontDeltaContext in Core.Picture has changed accordingly.

• SVG hyperlink change - hyperlinks no longer group primitives (although a group of primitives can be hyperlinked). The function xlinkGroup has been removed from Core.Picture, it is replaced by xlink. Primitives are now grouped with the function primGroup.

• Core.Picture - the argument order for the function rtextlabel has been changed, the positions of the angle and bottom-left corner have been swapped.

Modules

[Index]

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• wumpus-core-0.37.0.tar.gz [browse] (Cabal source package)
• Package description (revised from the package)

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Package maintainers

• StephenTetley

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