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gulp-marked-vega Build Status Coverage Status styled with prettier

NPM

gulp-marked-vega is a gulp plugin to replace marked-vega codeblocks with base64 image markdown tags so that any markdown parser can render the Vega or Vega-Lite charts as images.

Currently, only the marked-vega codebase markdown is supported. The image markdown is not supported yet.

API documentation can be found at https://e2fyi.github.io/gulp-marked-vega.

Installation

Yarn

yarn add gulp-marked-vega -D

Npm

npm install gulp-marked-vega -D

Usage

Gulp

Replacing marked-vega codeblocks with image. Export as markdown.

const gulp = require('gulp');
const marked_vega = require('gulp-marked-vega');

gulp
  .src('./test/sample.md')
  .pipe(marked_vega()) // replace codeblocks with image
  .pipe(gulp.dest('test/output')); // output as "test/output/sample.md"

Replacing marked-vega codeblocks with image. Export as HTML. Auto rename to <original_filename>.html.

const gulp = require('gulp');
const marked_vega = require('gulp-marked-vega');

gulp
  .src('./test/sample.md')
  .pipe(marked_vega(true)) // replace codeblocks with image and export as html
  .pipe(gulp.dest('test/output')); // output as "test/output/sample.html"

More details on how to use Gulp as part of your build chain can be found at their site.

Cli

There is also a cli to directly embed the Vega and Vega-Lite charts in your markdown file.

usage: mdvg.js [-h] [-v] -f FILE [-o OUTPUT] [--html]

cli to replace marked-vega codeblocks with base64 embedded charts.

Optional arguments:
  -h, --help            Show this help message and exit.
  -v, --version         Show program's version number and exit.
  -f FILE, --file FILE  Input markdown file to process
  -o OUTPUT, --output OUTPUT
                        Output file to write to
  --html                Convert to HTML

Embed chart only.

mdvg -f ./test/sample.md -o ./test/sample_.md

Embed and convert to HTML.

mdvg -f ./test/sample.md -o ./test/sample_.md --html

Special note on canvas

One of the underlaying lib to generate the image is canvas. canvas has some special dependencies. Hence, you will get many error message if these are not met. However, canvas-prebuilt is also been included to ensure that it will still work if canvas cannot be compiled properly.

Below is an extract from canvas repo:

You can quickly install the dependencies by using the command for your OS:

OS Command
OS X brew install pkg-config cairo pango libpng jpeg giflib
Ubuntu sudo apt-get install libcairo2-dev libjpeg8-dev libpango1.0-dev libgif-dev build-essential g++
Fedora sudo yum install cairo cairo-devel cairomm-devel libjpeg-turbo-devel pango pango-devel pangomm pangomm-devel giflib-devel
Solaris pkgin install cairo pango pkg-config xproto renderproto kbproto xextproto
Windows Instructions on their wiki

marked-vega custom Markdown Syntax

marked-vega introduces a few new markdown syntax.

1. Image markdown

Syntax

![vg|vega|vega-lite|vl](https://someurl/spec.json)

Example

![vega](barchart-vg.json)

2. Code markdown

Syntax

```vg|vega|vega-lite|vl
<Vega/Vega-Lite JSON specification>
or
<Vega/Vega-Lite JSON specification in YAML format>
```

Example - JSON specification

```vega-lite
{
  "data": {
    "values": [
      {"a": "A","b": 28}, {"a": "B","b": 55}, {"a": "C","b": 43},
      {"a": "D","b": 91}, {"a": "E","b": 81}, {"a": "F","b": 53},
      {"a": "G","b": 19}, {"a": "H","b": 87}, {"a": "I","b": 52}
    ]
  },
  "mark": "bar",
  "encoding": {
    "x": {"field": "a", "type": "ordinal"},
    "y": {"field": "b", "type": "quantitative"}
  }
}
```

Example - YAML specification

```vega-lite
data:
  values:
    - x: A
      y: 13
    - x: B
      y: 55
    - x: C
      y: 43
    - x: D
      y: 91      
    - x: E
      y: 81      
    - x: F
      y: 53      
    - x: G
      y: 19      
    - x: H
      y: 87      
    - x: I
      y: 52      
mark:
  bar
encoding:
  x:
    field: x
    type: ordinal
  y:
    field: y
    type: quantitative
```

Development

Compile and publish documentation to /docs.

npm run publish

Lint and Unit testing

npm test

Run demo

npm run demo

Resources