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https://github.com/lolipopj/mdimg
Convert Markdown or HTML to image!
https://github.com/lolipopj/mdimg
html image javascript markdown marked nodejs puppeteer
Last synced: about 2 hours ago
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Convert Markdown or HTML to image!
- Host: GitHub
- URL: https://github.com/lolipopj/mdimg
- Owner: LolipopJ
- Created: 2022-02-15T04:47:18.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2023-04-18T16:54:56.000Z (over 1 year ago)
- Last Synced: 2024-04-03T00:54:05.643Z (8 months ago)
- Topics: html, image, javascript, markdown, marked, nodejs, puppeteer
- Language: JavaScript
- Homepage: https://www.npmjs.com/package/mdimg
- Size: 1.16 MB
- Stars: 21
- Watchers: 1
- Forks: 8
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# mdimg
A tool that can be used to convert **Markdown** or **HTML** format text to an image.
## How does it work?
First, the script calls [marked](https://github.com/markedjs/marked) to parse Markdown into a HTML document. Next, use [Puppeteer](https://github.com/puppeteer/puppeteer) to start a headless browser and render the document with HTML and CSS templates. Finally, export our image through Puppeteer's [screenshot](https://pptr.dev/guides/screenshots/) API.
## Preview
Rendering results:
| MacOS | Windows | HTML Template | CSS Template | Notes |
| ------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ | ------------- | ------------ | ------------------------------------------------- |
| 
| 
| `default` | `default` |
| 
| 
| `default` | `empty` | Only use base stylesheets |
| 
| 
| `default` | `github` |
| 
| 
| `default` | `githubDark` | Should be used with `theme: "dark"` |
| 
| 
| `words` | `words` | It is recommended to use with **plain text only** |
## Requirements
This tool requires a LTS Node version (v18.0.0+).
If your node version is lower than 18, please use the legacy version [0.2.3](https://www.npmjs.com/package/mdimg/v/0.2.3).
## Installation
CLI:
```bash
npm install -g mdimg
```
In Node.js project:
```bash
npm install mdimg
```
## Usage
### CLI
Example:
```bash
mdimg -i path/to/input.md -o path/to/output.png -w 600 --css github
```
mdimg will read text from `path/to/input.md` and convert it to an image file `path/to/output.png`.
When using the command, you must specify either `-i` (input file, recommended) or `-t` (directly input text).
When using `-t` to input Markdown text directly, escape characters will **not be available**. To fix this, for example, you should replace `\n` with `
`.
You can always call `mdimg -h` to get complete help.
### In Node.js project
Import mdimg to your project:
```js
import { mdimg } from "mdimg";
```
Convert markdown file to an image:
```js
const convertRes = await mdimg({
inputFilename: "path/to/input.md",
outputFilename: "path/to/output.png",
width: 600,
cssTemplate: "github",
theme: "light",
// or with dark theme
// cssTemplate: "githubDark",
// theme: "dark",
});
console.log(
`Convert to image successfully!\nImage has been saved as \`${convertRes.path}\``,
);
```
Convert markdown text to blob:
```js
const convertRes = await mdimg({
inputText: "# Hello world",
encoding: "blob",
});
// import { writeFileSync } from "fs";
// writeFileSync("path/to/output.png", convertRes.data);
```
When using `mdimg()` method, you must specify either `inputFilename` (input file) or `inputText` (directly input text).
Here are all available options:
| Argument | Type | Default | Notes |
| -------------- | -------------------------------- | -------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| inputText | `String` | `undefined` | Input Markdown or HTML text directly. This option **has no effect** if `inputFilename` is specified |
| inputFilename | `String` | `undefined` | Read Markdown or HTML text from a file |
| outputFilename | `String` | `./mdimg_output/mdimg_${new Date()}.${type}` | Output binary image filename. Available file extensions: `jpeg`, `png`, `webp`. Available when `encoding` option is `binary` |
| type | `"jpeg" \| "png" \| "webp"` | `png` | File type of the image. Type will be inferred from `outputFilename` if specified |
| width | `Number` | `800` | Width in pixel of output image |
| height | `Number` | `100` | Min-height in pixel of output image. No less than `100` |
| encoding | `"base64" \| "binary" \| "blob"` | `binary` | Encode type of output image |
| quality | `Number` | `100` | Quality of the image, between 0-100. **Not applicable** to `png` image |
| htmlText | `String` | `undefined` | HTML rendering text |
| cssText | `String` | `undefined` | CSS rendering text |
| htmlTemplate | `String` | `default` | HTML rendering template. Available presets can be found in [`template/html`](./template/html/). If ends with `.html`, the mdimg will try to read local file. This option **has no effect** if `htmlText` is specified |
| cssTemplate | `String` | `default` | CSS rendering template. Available presets can be found in [`template/css`](./template/css/). If ends with `.css`, the mdimg will try to read local file. This option **has no effect** if `cssText` is specified |
| theme | `light` \| `dark` | `light` | Rendering color theme, will impact styles of code block and so on |
| extensions | `Boolean \| IExtensionOptions` | `true` | Configurations for [extensions](#extensions) |
| log | `Boolean` | `false` | Print execution logs via stderr |
| debug | `Boolean` | `false` | Whether to keep temporary HTML file after rendering |
| puppeteerProps | `LaunchOptions` | `undefined` | [Launch options](https://pptr.dev/api/puppeteer.puppeteerlaunchoptions) of Puppeteer |
Returns: `Promise`
| Key | Value Type | Notes |
| ---- | ------------------------ | ------------------------------------------------------------------------------------------------------------------------ |
| data | `string` \| `Uint8Array` | BASE64 encoded string (`encoding` is `base64`) or Uint8Array blob (`encoding` is `binary` or `blob`) of the output image |
| path | `string` | Path of output image. Available when `encoding` is `binary` |
| html | `string` | Rendered HTML document |
## Custom template
> **😍 Contribute to template presets via [pull requests](https://github.com/LolipopJ/mdimg/pulls) is welcomed!**
Template presets are stored in the `template` directory.
If you execute the following command:
```bash
mdimg --html custom --css custom
```
Or in Node.js project:
```js
await mdimg({
htmlTemplate: "custom",
cssTemplate: "custom",
});
```
The mdimg will read `template/html/custom.html` as HTML template and `template/css/custom.css` as CSS template in the mdimg directory to render the image.
### HTML Template
Create a new `.html` file in `template/html` directory.
There is only one rule you need to follow: an element with id `mdimg-body` wrapping an element with class `markdown-body`.
The simplest example:
```html
```
The mdimg will put the parsed HTML content in the element which `class="markdown-body"` (elements inside will be **replaced**), and finally generate the image for the whole element which `id="mdimg-body"`.
### CSS Template
Nothing to note, create a new `.css` file in `template/css` directory and then make your style!
For further development, it is recommended that write `.scss` or `.sass` files in the `template/scss` directory, and use the following command to generate CSS templates:
```bash
# Build .scss and .sass files
yarn rollup:sass
```
CSS templates with the corresponding name will be generated in `template/css` directory.
## Local Template
Template presets may not often meet your needs. If you already know the specifications of [HTML template](#html-template) and [CSS template](#css-template), you can pass the template directly. There are two methods:
1. Using local template file. Pass a local filepath with the **file extension `.html` and `.css`** through options `--html` and `--css` with CLI (`htmlTemplate` and `cssTemplate` with Node.js).
2. Using template text. Pass template text through `--htmlText` and `--cssText` with CLI (`htmlText` and `cssText` with Node.js).
CLI:
```bash
# use local file
mdimg --html path/to/custom.html --css path/to/custom.css
# use text directly
mdimg --htmlText '
' --cssText '@import "https://cdn.jsdelivr.net/npm/normalize.css/normalize.min.css"; .markdown-body { padding: 6rem 4rem; }'
```
Or in Node.js project:
```js
// use local file
await mdimg({
htmlTemplate: "path/to/custom.html",
cssTemplate: "path/to/custom.css",
});
// use text directly
await mdimg({
htmlText: `
`,
cssText: `@import "https://cdn.jsdelivr.net/npm/normalize.css/normalize.min.css";
.markdown-body {
padding: 6rem 4rem;
}`,
});
```
## Extensions
Extensions are default enabled. You can easily configuration them in Node.js:
```ts
await mdimg({
extensions: false, // disable all extensions
});
await mdimg({
extensions: {
highlightJs: false, // disable highlight.js
mathJax: {
// further configuration for MathJax
// ...
},
mermaid: true, // enable mermaid (by default)
},
});
```
In CLI, you can only enable or disable extensions globally:
```bash
mdimg --extensions false # disable all extensions
```
### Extended Syntaxes
Some extended syntaxes, such as LaTeX, can't be parsed by pure marked correctly. To solve this problem, the mdimg introduces some third-party libraries to enhance rendering capabilities. Below are introduced libraries:
#### [MathJax](https://github.com/mathjax/MathJax)
> MathJax is an open-source JavaScript display engine for **LaTeX**, **MathML**, and **AsciiMath** notation.
⚠️ The single dollar sign `$` is **not enabled by default** to render inline LaTeX. Because It is used too frequently in normal text, so if you want to use it for math delimiters, you must specify it explicitly. In Node.js project:
```ts
await mdimg({
extensions: {
mathJax: {
tex: {
inlineMath: [
["$", "$"],
["\\(", "\\)"],
],
},
},
},
});
```
CLI doesn't support to configuration extensions, so you need to override MathJax options in HTML template directly:
```html
MathJax = {
tex: {
inlineMath: [
["$", "$"],
["\\(", "\\)"],
],
},
};
```
```bash
mdimg --html path/to/template.html
```
⚠️ Due to the [parse behaviors](https://andrzejq.github.io/markdown-mathjax/editor/md-mhj.html) between marked and MathJax: "\\" before any ASCII punctuation character is backslash escape, so "\\\\" (or "\\,") should be written as "\\\\\\\\" (or "\\\\,"). You need to manually replace characters or **wrap the LaTeX code in a `
` block**. Example:
```md
$$
A_{m,n} =
\begin{pmatrix}
a_{1,1} & a_{1,2} & \cdots & a_{1,n} \\
a_{2,1} & a_{2,2} & \cdots & a_{2,n} \\
\vdots & \vdots & \ddots & \vdots \\
a_{m,1} & a_{m,2} & \cdots & a_{m,n}
\end{pmatrix}
$$
```
#### [Mermaid](https://github.com/mermaid-js/mermaid)
> Mermaid is a JavaScript-based **diagramming** and **charting** tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams.
Sequence diagram example:
````md
```mermaid
sequenceDiagram
Alice->>Bob: Hello Bob, how are you ?
Bob->>Alice: Fine, thank you. And you?
create participant Carl
Alice->>Carl: Hi Carl!
create actor D as Donald
Carl->>D: Hi!
destroy Carl
Alice-xCarl: We are too many
destroy Bob
Bob->>Alice: I agree
```
````
### Other Extensions
#### [Highlight.js](https://github.com/highlightjs/highlight.js)
> Highlight.js is a syntax highlighter.
## Development
```bash
git clone https://github.com/LolipopJ/mdimg.git
cd mdimg
yarn
```
### Lint
```bash
# Check lint rules
yarn lint
# Check lint rules and fix resolvable errors
yarn lint:fix
```
### Build
```bash
# Build .js, .scss and .sass files
yarn build
```
### Test
```bash
# Build productions before testing
yarn build
# Run test cases
yarn test
```
## Inspired by
- [md2img](https://github.com/363797271/md2img). Provided me the idea and a complete feasible solution.