XML-ESC/POS

XML-ESC/POS is a simple python library that allows you to print receipts on ESC/POS Compatible receipt printers with a simple utf8 encoded XML format similar to HTML. Barcode, pictures, text encoding are automatically handled. No more dicking around with esc-pos commands !

The following example is self-explanatory:

<receipt>
    <h1>Receipt!</h1>
    <h2>div,span,p,ul,ol are also supported</h2>:w
    <line>
        <left>Product</left>
        <right>0.15€</right>
    </line>
    <hr />
    <line size='double-height'>
        <left>TOTAL</left>
        <right>0.15€</right>
    </line>
    <barcode encoding='ean13'>
        5449000000996
    </barcode>
    <cashdraw /> 
    <cut />
</receipt>

And printing from python is quite easy, you just need the USB product / vendor id of your printer. Some common ids are found in supported_devices.py

from xmlescpos.printer import Usb
printer = Usb(0x04b8,0x0e03)
printer.receipt("<div>Hello World!</div>")

Install

sudo pip install pyxmlescpos

Limitations

The utf8 support is incomplete, mostly asian languages are not working. Documentation is hard to find, support relies on region-specific hardware, etc. There is some very basic support for Japanese.

Documentation

XML Structure

The library prints receipts defined by utf-8 encoded XML documents. The tags and structure of the document are in many ways similar to HTML. The two main differences between XML-ESC/POS and HTML, is the presence of ESC/POS specific tags, and the lack of CSS. Oh, and it is XML based, so you must provide valid XML, or you'll get a traceback on your receipt.

The styling is done with custom attributes on the elements themselves. The styling is inherited by child elements.

Supported HTML Tags

Inline Tags

• span,em,b

Block level Tags

• p,div,section,article,header,footer,li,h1-5,hr

List tags

• ul,ol

The indentation width is determined by the tabwidth attribute, which specifies the indentation in number of white space characters. tabwidth is inherited by child elements, like all styling attributes.

ul elements also support the bullet attribute which specifies the character used to represent bullets.

<ul tabwidth='3' bullet='-'>
    <li>foo</li>
    <li>bar</li>
</ul>

Image Tags

The img tag prints the picture specified by the src attribute. The src attribute must contain the picture encoded in png, gif or jpeg in a base64 data-url.

<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAQMAA..." />

Esc/Pos Specific tags

• cut, cuts the recipt
• partialcut, partially cuts the receipt
• cashdraw, activates the cash-drawer connected to the printer

Barcode Tags

It is possible to include barcodes in your receipt with the barcode tag. The encoding attribute lets you specify the barcode encoding used, and its presence is mandatory. The following encodings are supported: UPC-A,UPC-E,EAN13,EAN8,CODE39,ITF,NW7.

<barcode encoding="EAN13">
    5400113509509
</barcode>

Line Tag

The line tag is used to quickly layout receipt lines. Its child elements must have either the left or right tag, and will be aligned left or right on the same line. There is a hard limit between the left and right part of the line, and content overflow is hidden. The placement of the limit is given by the line-ratio attribute, which is the ratio of the left part's width with the total width of the line. A ratio of 0.5 ( the default ) thus divides the line in two equal parts.

<line line-ratio='0.6'>
    <left>Product Name</left>
    <right>$0.15</right>
</line>

Value Tag

The value tag is used to format numerical values. It allows to specify the number of digits, the decimal and thousands separator independently of the formatting of the provided number. The following attributes are supported:

• value-decimals : The number of decimals
• value-width : The number will be left-padded with zeroes until its formatting has that many characters.
• value-decimals-separator : The character used to seprate the decimal and integer part of the number.
• value-thousands-separator : The character used to separate thousands.
• value-autoint : The number will not print decimals if it is an integer
• value-symbol : The unit symbol will be placed before or after the number
• value-symbol-position : before or after

<value value-symbol='€' value-symbol-position='after'>
    3.1415
</value>

Those attributes are inherited, and can thus be specified once and for all on the receipt's root element.

Styling Attributes

The following attributes are used to style the elements. They are inherited and can be applied to any element.

• align: left,right or center. Specifies the text alignment.
• underline: off or on or double
• bold: off or on
• size: normal,double,double-height,double-width, the font size.
• font: a or b, the font used (two fonts ought to be enough ... )
• width: the width of block level elements, in characters. (default 48)
• indent: The indentation (in tabs) before a block level element.
• tabwidth: The number of spaces in a single indentation level (default 2)
• color : black or red