HTML2Thermal

JavaScript library to translate subset of HTML into commands which would be executed on the thermal printer.

Library is based on the popular node-thermal-printer module which provides adapters for EPSON and STAR thermal printers command line printing.

Motivation

Compare the code in HTML and direct commands for printer.

HTML:

<center>
    <p>dsdasdas</p>
    <div style="font-weight: bold">oneone</div>
</center>

Direct JS commands:

printer.alignCenter()
printer.print('dsdasdas')
printer.newLine()
printer.bold(true)
printer.print('oneone')
printer.bold(true)
printer.newLine()
printer.alignLeft()

HTML code version:

• allows to create preview of what will be printed in the browser
• makes code more readable
• reduces integration time

Installation

npm install html2thermal node-thermal-printer

Linux specific

Linux requires build-essentials

sudo apt-get install build-essential

Documentation

Library exports 2 functions:

1. convert(xml, characterSet = 'SLOVENIA') converts xml to the thermal printer commands.
   • xml as XML code to be converted to commands
   • characterSet
2. execute(printer, xml, isCut = true) executes the commands on the thermal printer.
   • printer as an instance of the printer from the node-thermal-printer
   • xml as XML code to be executed on the thermal printer
   • isCut defines if cut operation should be executed at the end of the printing process

Supported tags

• <beep/> perform sound of an internal beeper if present
• <br/> breaks the line (new line)
• <b>...</b> sets text bold
• <center>...</center> aligns text to center
• <left>...</left> aligns text to left
• <right>...</right> aligns text to right
• <cut /> cuts the paper if printer supports it
• <partialcut /> cuts the paper and leaves the bridge in the middle if printer supports it
• <div>...</div> isolates content on the separate line
• <p>...</p> isolates content on the separate line
• <doubleheight>...</doubleheight> sets text to double height
• <u>...</u> sets underline to the text
• <ud>...</ud> sets double underline or thick to the text
• <doublewidth>...</doublewidth> sets text to double width
• <fonta>...</fonta> changes text font to the first supported (A or default)
• <fontb>...</fontb> changes text font to the second supported (B)
• <hr /> draws the line-separator
• <img src="https://github.com/knyga/html2thermal/raw/master/.." height="..." width="..." /> prints the image from src (file:, http:, https:, data:, ...), width and height in pixels are optional
• <invert>...</invert> inverts background and foreground colors
• <normal>...</normal> resets all text settings to normal, redundant operation
• <opencashdrawer /> opens cash drawer if present
• <code128 data="..." /> prints code128 bar code with data provided in the data property
• <qrcode data="..." /> prints QR code with data provided in the data property
• <quadarea>...</quadarea> sets text to quad area
• <rotate180>...</rotate180> prints content upside down
• <table>...</table> table
• <tr>...</tr> table row
• <td width="..." align="..." bold="..." style="...">...<td> cell of the table row, width property is optional and in factor (0.5, 0.25, ...), align property is optional (left, right, center), bold property is optional (true), style property is optional

Supported style properties

• font-style: bold sets text bold (NOTE: no support for number value yet)

If no tag provided, then print operation will be executed.

Character sets

• PC437_USA
• PC850_MULTILINGUAL
• PC860_PORTUGUESEƒ
• PC863_CANADIAN_FRENCH
• PC865_NORDIC
• PC851_GREEK
• PC857_TURKISH
• PC737_GREEK
• ISO8859_7_GREEK
• WPC1252
• PC866_CYRILLIC2
• PC852_LATIN2
• SLOVENIA
• PC858_EURO
• WPC775_BALTIC_RIM
• PC855_CYRILLIC
• PC861_ICELANDIC
• PC862_HEBREW
• PC864_ARABIC
• PC869_GREEK
• ISO8859_2_LATIN2
• ISO8859_15_LATIN9
• PC1125_UKRANIAN
• WPC1250_LATIN2
• WPC1251_CYRILLIC
• WPC1253_GREEK
• WPC1254_TURKISH
• WPC1255_HEBREW
• WPC1256_ARABIC
• WPC1257_BALTIC_RIM
• WPC1258_VIETNAMESE
• KZ1048_KAZAKHSTAN

Example

const printer = require('node-thermal-printer')
const {execute} = require('html2thermal')
printer.init({
  type: 'epson',
  // If you connect over TCP
  interface: 'tcp://192.168.192.168',
})

const template = `
<div>hello world</div>
<p>it is</p>
<p>me
me</p>
`

execute(printer, template);

Licence

HTML2Thermal is MIT licenсed.