Library which acts as a toolchain which simplfies the process of PDFs generation out of HTML which can be used with POS receipt printers.

Allows conversion of HTML into long and narrow PDF files which can be passed to CUPS-compatible receipts printer.

Can process basic HTML 4 supported by htmldoc.

NuGet Link

https://www.nuget.org/packages/IDCT.PosPdfAssistant/

Functions

public Box HtmlToReceipt(string html, string outputFilePath, HtmldocOptions? htmldocOptions = null)

Main method which covers all of the others in a single process. Converts HTML string into a trimmed single-page PDF file. htmldocOptions allow to set width in milimeters, bottom padding to avoid exact trimming of the whitespace in the bottom of the file, default font and its size.

Returns Box which provides width and height in points, inches and milimeters, useful for printers which require exact size to print on a paper roll.

Partial methods

public void HtmlToPdf(string html, string outputFilePath, HtmldocOptions? htmldocOptions = null)

Converts HTML to a PDF file with parameters defined in htmldocOptions. By default a very long and narrow PDF. Main difference from HtmlToReceipt is the fact that this method does not call other functions like CombineLongPdf or TrimPdf which may result in multiple pages and no trimming of the remaining whitespace.

public static void CombineLongPdf(string inputFilePath, string outputFilePath)

Combines pages of a PDF file into a single long page. Takes width from first page.

public static Box TrimPdf(string inputFilePath, string outputFilePath, int bottomMargin = 0)

Trims a PDF file, removes remaining white space at the end, supports keeping a margin in pixels.

Returns Box which provides width and height in points, inches and milimeters, useful for printers which require exact size to print on a paper roll.

Sample usage

Main namespace is IDCT, so for example to generate a simple receipt:

using IDCT;
using IDCT.Type;

PosPdfAssistant pdfAssistant = new();

string html = "" +
    "<html>" +
    "<body>" +
    "<center>" + DateTime.Now.ToLocalTime().ToString() + "</center>" +
    "<p><img src='C:\\path\\to\\file\\logo.png' width='100%'></p>" +
    "<table>" +
    "<tr><td width='100%'><b>Koku-Kola</b></td><td>3.14</td>" +
    "<tr><td width='100%'><b>Pefsi</b></td><td>6.14</td>" +
    "<tr><td width='100%'><b>Lymbark</b></td><td>2.30</td>" +
    "</table>" +
    "<hr>" +
    "<table>" +
    "<tr><td width='100%'><b>Sum</b></td><td>11,58</td>" +
    "</table>" +
    "</body>" +
    "</html>";

var size = pdfAssistant.HtmlToReceipt(html, "out.pdf", new HtmldocOptions() { Gray = true, PdfSupportedFont = PdfSupportedFont.Monospace });

Console.WriteLine(String.Format("Size in points: {0}x{1}pt", size.Width.Point, size.Height.Point));
Console.WriteLine(String.Format("Size in inches: {0}x{1}cm", size.Width.Inch, size.Height.Inch));
Console.WriteLine(String.Format("Size in milimeters: {0}x{1}mm", size.Width.Millimeter, size.Height.Millimeter));

Will result in a PDF looking like this:

Sample PDF screenshot

Sample execution results also in output to console:

Size in points: 136x237pt
Size in inches: 1,8888888888888888x3,2916666666666665cm
Size in milimeters: 47,977777777777774x83,60833333333332mm

With some printers it may be require to provide exact size, for example with Custom Engineering PLUS2:

lpr -H 172.20.0.3 -o PrintDensity=7Density+37 -o PageSize=Custom.136x237pt -o orientation-requested=3 -P printer out.pdf

Sample PDF print

Installation and requirements

Follow nuget instructions, for example to install with .NET Cli:

dotnet add package IDCT.PosPdfAssistant

Library supports Windows, OSX and Linux (tested on Debian and WSL).

htmldoc application is required. It must be installed in one of the following ways:

Available in the system, for example by installing it using Windows installer, or by apt get. Ensure that it is present in PATH enviromental variable.
By placing htmldoc in the same folder as your application which includes the library.
By providing path to htmldoc in the constructor of the instance: public PosPdfAssistant(string? htmldocPath = null)

.NET 6 or newer is required.

Depends also on open-source projects:

PDFsharp, version at least 6.0.0 (https://docs.pdfsharp.net/)
Docnet.Core, version at least 2.6.0 (https://github.com/GowenGit/docnet)

License

This application is FREE, under MIT license which means that by default without any support. At the time of writing PDFsharp and Docnet.Core are also using MIT.

Support and troubleshooting

Support is provided via e-mail . Issues or code updates reported via GitHub are more than welcome!

Link to GitHub: https://github.com/ideaconnect/pos-printer-pdf-generator

TODO

Version 2.x is meant to be fully tested using Unit and Functional Tests.

Version 3.x will attempt to get rid of htmldoc dependency in favor or parsing HTML internally.

IDCT.PosPdfAssistant [C#]