This module gives access to the ascii diagram parser and SVG renderer.

Ascii diagram, transform your ASCII art drawing to a nicer representation

                /---------+
+---------+     |         |
|  ASCII  +---->| Diagram |
+---------+     |         |
|{flat}   |     +--+------/
\---*-----/<=======/
::: .flat .filled_shape { fill: #DDD; }

To render the diagram as a PNG file, you have to use the library rasterific-svg and JuicyPixels.

As a sample usage, to save a diagram to png, you can use the following snippet.

import Codec.Picture( writePng )
import Text.AsciiDiagram( imageOfDiagram )
import Graphics.Rasterific.Svg( loadCreateFontCache )

saveDiagramToFile :: FilePath -> Diagram -> IO ()
saveDiagramToFile path diag = do
  cache <- loadCreateFontCache "asciidiagram-fonty-fontcache"
  imageOfDiagram cache 96 diag
  writePng path img

Ascii diagram, transform your ASCII art drawing to a nicer representation

                /---------+
+---------+     |         |
|  ASCII  +---->| Diagram |
+---------+     |         |
|{flat}   |     +--+------/
\---*-----/<=======/
::: .flat .filled_shape { fill: #DED; }

The basic syntax of asciidiagrams is made of lines made out of '-' and '|' characters. They can be connected with anchors like '+' (direct connection) or '\' and '/' (smooth connections)

 -----       
   -------   
             
 |  |        
 |  |        
 |  \----    
 |           
 +-----      

You can use dashed lines by using : for vertical lines or '=' for horizontal line

 -----       
   -=-----   
             
 |  :        
 |  |        
 |  \----    
 |           
 +--=--      

Arrows are made out of the '<', '>', '^' and 'v' characters. If the arrows are not connected to any lines, the text is left as is.

     ^
     |
     |
<----+---->
     |  < > v ^
     |
     v

If the lines are closed, then it is detected as such and rendered differently

  +------+
  |      |
  |      +--+
  |      |  |
  +---+--+  |
      |     |
      +-----+

If any of the segment posess one of the dashing markers (':' or '=') Then the full shape will be dashed.

  +--+  +--+  +=-+  +=-+
  |  |  :  |  |  |  |  :
  +--+  +--+  +--+  +-=+

Any of the angle of a shape can curved one of the smooth corner anchor ('\' or '/')

  /--+  +--\  +--+  /--+
  |  |  |  |  |  |  |  |
  +--+  +--+  \--+  +--+

  /--+  /--\  /--+  /--\ .
  |  |  |  |  |  |  |  |
  +--/  +--+  \--/  +--/

  /--\ .
  |  |
  \--/
.

Adding a '*' on a line or on a shape add a little circle on it. If the bullet is not attached to any shape or lines, then it will be render like any other text.

  *-*-*
  |   |  *----*
  +---/       |
          * * *

When used at connection points, it behaves like the '+' anchor.

The shapes can ba annotated with a tag like `{tagname}`. Tags will be inserted in the class attribute of the shape and can then be stylized with a CSS.

 +--------+         +--------+
 | Source +-------->| op1    |
 | {src}  |         \---+----/
 +--------+             |
            +-------*<--/
 +------+<--| op2   |
 | Dest |   +-------+
 |{dst} |
 +------+

::: .src .filled_shape { fill: #AAF; }
::: .dst .filled_shape { stroke: #FAA; stroke-width: 3px; }

Inline css styles are introduced with the ":::" prefix at the beginning of the line. They are introduced in the style section of the generated CSS file

The generated geometry also possess some predefined class which are overidable:

• "dashed_elem" is applied on every dashed element.
• "filled_shape" is applied on every closed shape.
• "arrow_head" is applied on arrow head.
• "bullet" on every bullet placed on a shape or line.
• "line_element" on every line element, this include the arrow head.

You can then customize the appearance of the diagram as you want.

Starting with version 1.3, all shapes, text and lines are hierachised, a shape within a shape will be integrated within the same group. This allows more complex styling:

 /------------------------------------------------------\ .
 |s100                                                  |
 |    /----------------------------\                    |
 |    |s1         /--------\       |  e1    /--------\  |
 |    |      *--->|  s2    |       +------->|  s10   |  |
 |    +----+      \---+----/       |        \--------/  |
 |    | i4 |          |            |           ^        |
 |    |{ii}+---------\| e1  {lo}   |           |        |
 |    +----+         vv            | ealarm    |        |   e0      /-------------\ .
 |    |            /--------\      +-----------/        +---------->|    s50      |
 |    +----\       | s3 {lu}|      |                    |           \-------------/
 |    | o5 |   e2  \--+-----/      |                    |
 |    |{oo}|<---------/            |<-\                 |
 |    \-+--+--------------------+--/  |                 |
 |      |                       |     | eReset          |
 |      |                       \-----/                 |
 |      v                                               |
 |  /--------\                                          |
 |  |  s20   |                  {li}                    |
 |  \--------/                                          |
 \------------------------------------------------------/

::: .li .line_element { stroke: purple; }
::: .li .arrow_head, .li text { fill: gray; }
::: .lo .line_element { stroke: blue; }
::: .lo .arrow_head, .lo text { fill: green; }
::: .lu .line_element { stroke: red; }
::: .lu .arrow_head, .lu text { fill: orange; }
::: .ii .filled_shape { fill: #DDF; }
::: .ii text { fill: blue; }
::: .oo .filled_shape { fill: #DFD; }
::: .oo text { fill: pink; }

In the previous example, we can see that the lines color are 'shape scoped' and the tag applied to the shape above them applies to them

From version 1.3, you can substitute the shape of your element with one from a shape library. Right now the shape library is relatively small:

 +---------+  +----------+
 |         |  |          |
 | circle  |  |          |
 |         |  |    io    |
 |{circle} |  | {io}     |
 +---------+  +----------+

 +----------+  +----------+
 |document  |  |          |
 |          |  |          |
 |          |  | storage  |
 |{document}|  | {storage}|
 +----------+  +----------+

::: .circle .filled_shape { shape: circle; }
::: .document .filled_shape { shape: document; }
::: .storage .filled_shape { shape: storage; }
::: .io .filled_shape { shape: io; }

The mechanism use CSS styling to change the shape, if a CSS rule possess a shape pseudo attribute, then the generated shape is replaced with a SVG use tag with the value of the shape attribute as href

But, you can create your own style library and change the default stylesheet. You can retrieve the default one with the shell command `asciidiagram --dump-library default-lib.svg`

You can then add your own symbols tag in it and use it by calling `asciidiagram --with-library your-lib.svg`.