R Wrapper for 'pikchr' (PIC) Diagram Language

An 'R' interface to 'pikchr' (< https://pikchr.org>, pronounced "picture"), a 'PIC'-like markup language for creating diagrams within technical documentation. Originally developed by Brian Kernighan, 'PIC' has been adapted into 'pikchr' by D. Richard Hipp, the creator of 'SQLite'. 'pikchr' is designed to be embedded in fenced code blocks of Markdown or other documentation markup languages, making it ideal for generating diagrams in text-based formats. This package allows R users to seamlessly integrate the descriptive syntax of 'pikchr' for diagram creation directly within the 'R' environment.

pikchr

Welcome to the pikchr package website, an R interface for the PIC diagramming language, powered by the parser from https://pikchr.org. The pikchr package allows you to create diagrams directly within R, combining simplicity and precision for efficient diagram generation.

With pikchr, you can produce complex diagrams for documentation, presentations, articles, and more, all from your R environment. The straightforward nature of the PIC language, paired with the power of R, makes this package a valuable tool for those needing precise, customizable visualizations in academic, technical, and scientific projects.

The {pikchr} knitr engine works seamlessly with both RMarkdown and Quarto documents, supporting all output formats: HTML, PDF (LaTeX), Word (DOCX), EPUB, Typst, and more. It also supports standard knitr features like fig.cap, fig.alt, fig.align, and dpi.

## Installation

You can install directly from CRAN or the development version of pikchr from GitHub with:

# install.packages("pak")
pak::pak("StrategicProjects/pikchr")

library(pikchr)

pikchr('
/*
basic example code
*/
arrow right 200% "Rmarkdown" "Source" # teste
box rad 10px "Rmarkdown" "(knitr)" bold  fit
arrow right 200% "HTML+SVG" "Output" 
arrow <-> down from last box.s
box same "Pikchr" "(pikchr.c)" bold fit
',
       width = "75%", 
       height = "auto",
       fontSize = '75%',
       fontFamily = "Flamenco")

You can also use the {pikchr} engine in RMarkdown or Quarto documents. It supports chunk options via the #| YAML syntax:

```{pikchr}
#| width: 50%
#| height: auto
#| align: center
#| fontSize: 14
#| fontFamily: Jost
#| fig.cap: "A pikchr diagram"
#| fig.alt: "Diagram showing the RMarkdown to HTML+SVG pipeline"
/*
  basic example code in a markdown chunk.
*/
  arrow right 200% "Rmarkdown" "Source" # teste
box rad 10px "Rmarkdown" "(knitr)"  fit fill 0xEE964B
arrow right 200% "HTML+SVG" "Output" 
arrow <-> down from last box.s
box same "Pikchr" "(pikchr.c)" fit fill 0xF4D35E
```

lgt = .2

define hex_up { 
    A:line right $1*(sqrt(3)/2) down $1/2 \
        then down $1 \
        then down $1/2 left $1*(sqrt(3)/2) \
        then up $1/2 left $1*(sqrt(3)/2) \
        then up $1 \
        then right $1*(sqrt(3)/2) up $1/2 \
        close color $3 fill $4
    text $2 at last .c color $5
}

define hex_dgr {
   P:(0,0)
   C1: circle rad .01 with .c at P.c thin color $2
   C2: circle rad .01 with .c at C1.c + ($1*(sqrt(3)/2), -$1/2) thin color $2
   C3: circle rad .01 with .c at C2.c + (0, -$1) thin  color $2
   C4: circle rad .01 with .c at C3.c + (-$1*(sqrt(3)/2), -$1/2) thin color $2
   C5: circle rad .01 with .c at C4.c + (-$1*(sqrt(3)/2), $1/2) thin color $2
   C6: circle rad .01 with .c at C5.c + (0, $1) thin color $2
   L1: line from C1.se to C2.nw thin color $2
   L2: line from C2.s to C3.n thin color $2
   L3: line from C3.sw to C4.ne thin color $2
   L4: line from C4.nw to C5.se thin color $2
   L5: line from C5.n to C6.s thin color $2
   L6: line from C6.ne to C1.sw thin color $2
   
}


H2: [hex_up(lgt ,  "Pikchr" small, 0x196F3D, 0x27AE60, white)]
H3: [hex_dgr(lgt*.8, 0x7DCEA0)] with .c at H2.c
H4: [hex_dgr(lgt*.6, 0x52BE80)] with .c at H2.c