## PGF diagrams backend
`diagrams-pgf` is a [PGF] backend for [diagrams]. Diagrams is a powerful, flexible, declarative domain-specific language for creating vector graphics, using the [Haskell programming language][haskell].
[PGF]: http://sourceforge.net/projects/pgf/
[diagrams]: http://projects.haskell.org/diagrams/
[haskell]: http://www.haskell.org/haskellwiki/Haskell
PGF is a TeX macro package for generating graphics. It is platform- and format-independent and works together with the most important TeX backend drivers, including pdftex and dvips.
`diagrams-pgf` is a work in progress, it supports the basic features of diagrams with the following features:
- LaTeX, ConTeXt and plain TeX support
- direct PDF generation using a TeX distribution (e.g. [texlive](https://www.tug.org/texlive/)) via [texrunner].
### Usage
A simple example that uses diagrams-pgf to draw a square.
```haskell
import Diagrams.Prelude
import Diagrams.Backend.PGF.CmdLine
b1 = square 20 # lwG 0.05
main = defaultMain (pad 1.1 b1)
```
Save this to file named `square.hs` and compile this program:
```
ghc --make square.hs
```
This will generate an executable which, when run produces a TeX (or PDF) file. Run the
executable with the `--help` option to find out more about how to call it.
```
$ ./square --help
square
Usage: square [-?|--help] [-w|--width WIDTH] [-h|--height HEIGHT]
[-o|--output OUTPUT] [-f|--format FORMAT] [-a|--standalone]
[-r|--readable] [-l|--loop] [-s|--src ARG]
[-i|--interval INTERVAL]
Command-line diagram generation.
Available options:
-?,--help Show this help text
-w,--width WIDTH Desired WIDTH of the output image
-h,--height HEIGHT Desired HEIGHT of the output image
-o,--output OUTPUT OUTPUT file
-f,--format FORMAT l for LaTeX, c for ConTeXt, p for plain
TeX (default: LaTeX)
-a,--standalone Produce standalone .tex output
-r,--readable Indent lines
-l,--loop Run in a self-recompiling loop
-s,--src ARG Source file to watch
-i,--interval INTERVAL When running in a loop, check for changes every
INTERVAL seconds.
```
If no output file is given, output is send to `stdout`. Supported outputs are `.tex` and `.pdf`. PDF generation is done using [texrunner].
[texrunner]: http://www.github.com/cchalmers/texrunner
```
$ ./Square -o square.tex
$ cat ./square.tex
\begin{pgfpicture}
\pgfpathrectangle{\pgfpointorigin}{\pgfqpoint{22.0000px}{22.0000px}}
\pgfusepath{use as bounding box}
\begin{pgfscope}
\begin{pgfscope}
\pgfpathmoveto{\pgfqpoint{21.0000px}{1.0000px}}
\pgfpathlineto{\pgfqpoint{21.0000px}{21.0000px}}
\pgfpathlineto{\pgfqpoint{1.0000px}{21.0000px}}
\pgfpathlineto{\pgfqpoint{1.0000px}{1.0000px}}
\pgfpathlineto{\pgfqpoint{21.0000px}{1.0000px}}
\pgfpathclose
\definecolor{sc}{rgb}{0.0000,0.0000,0.0000}
\pgfsetstrokecolor{sc}
\pgfsetlinewidth{0.0132mm}
\pgfusepath{stroke}
\end{pgfscope}
\end{pgfscope}
\end{pgfpicture}
```
### Typesetting
`pgf-diagrams` allows typesetting TeX commands and can calculate the corresponding envelope. See the [hbox example] to see how get envelopes of text:
[hbox example]: examples/hbox.hs
### Missing features
The following features are not currently supported:
- selecting fonts (italic and bold work)
- gradients