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Line Printer Class in C#

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26 Sep 2008Public Domain1 min read 267.7K   8.7K   64   115
A simple C# class for printing on old dot matrix line printers

Introduction

This class simplifies the job of printing text on line printers, in C#. I had an application that needed to print on one of such printers, so I ended up writing this helper class. Basically, it's a wrapper for the spooler API (winspool.drv); the text to be printed is sent in "RAW" mode to the spooler so that no graphics printing is involved.

Using the Code

The use of the class is pretty easy. First, the desired printing device is selected by either writing the PrinterName property or by calling the ChoosePrinter() method:

C#
LPrinter MyPrinter = new LPrinter(); // creates the printer object
MyPrinter.ChoosePrinter();// let user choose the printer device

// alternatively:
MyPrinter.PrinterName = "Epson FX-80";
// uses a specific named printer

The actual printing is done like this:

C#
MyPrinter.Open("Document Title Here"); // opens and tells the spooler the document title
MyPrinter.Print("Some text....\r\n");  // actual printing (CR+LFs are needed)
MyPrinter.Print("\x0C");               // sends a form feed (ejects the paper)
MyPrinter.Close();                     // Close the spooler

All methods Open(), Print(), Close(), and ChoosePrinter() return a boolean, in case you want to check if the operation was successful.

Some basic text effects can be achieved by sending control codes to the printer, according to the following table:

Code Description
14 enlarged characters on
20 enlarged characters off
15 compressed characters on
18 compressed characters off
ESC + "E" bold characters on
ESC + "F" bold characters off
12 FF (form feed)

For more code, check the printer's manual.

Points of Interest

Unfortunately, there is no easy way to tell if an installed printer is a line printer or a graphical one (laser or inkjet), so I was not able to filter the print dialog of ChoosePrinter(), making it display only line printers. This means that the user has to choose the right printer.

History

  • 29-Sep-2008: First (and possibly only one) version

License

This article, along with any associated source code and files, is licensed under A Public Domain dedication


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Comments and Discussions

 
QuestionMake gujrati print in C# Pin
CHAVADA SURAJ12-Dec-11 15:03
CHAVADA SURAJ12-Dec-11 15:03 
AnswerRe: Make gujrati print in C# Pin
Antonino Porcino12-Dec-11 21:36
Antonino Porcino12-Dec-11 21:36 
AnswerRe: Make gujrati print in C# Pin
lukac23-Dec-11 0:39
professionallukac23-Dec-11 0:39 
QuestionLine Printer Class problem Pin
Zil-e-Huma16-Aug-11 1:03
Zil-e-Huma16-Aug-11 1:03 
AnswerRe: Line Printer Class problem Pin
Antonino Porcino16-Aug-11 3:55
Antonino Porcino16-Aug-11 3:55 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma16-Aug-11 17:50
Zil-e-Huma16-Aug-11 17:50 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma16-Aug-11 19:42
Zil-e-Huma16-Aug-11 19:42 
GeneralRe: Line Printer Class problem Pin
Antonino Porcino16-Aug-11 20:57
Antonino Porcino16-Aug-11 20:57 
Sorry, I don't have access to a physical Line Printer right now, so I can't write and test the code for you. More or less it should be something like this:

First, you need to be able to send "bytes" to the printer with a method like this:

public void PrintByte(LinePrinter PRN, int b)
{
   byte[] buf = new byte[1];
   buf[0] = (byte) b;
   System.Text.UTF8Encoding enc = new System.Text.UTF8Encoding();
   string str = enc.GetString(buf);
   PRN.Print(str);
}


then you need a bitmap scanning routine that converts pixels into printer codes:

public void PrintBitmap(LinePrinter PRN, Bitmap bmp)
{
   int width  = bmp.Width;
   int height = bmp.Height - bmp.Height % 8;

   int numbytes = height;
   int lo = numbytes & 255;
   int hi = numbytes >> 8;

   for(int y=0;y<height;y+=8)
   {
       PrintByte(27);
       PrintByte(75);
       PrintByte(lo);
       PrintByte(hi);

       for(int x=0;x<width;x++)
       {
          int b = 0;
          for(int i=0;i<=7;i++)
          {
             Color c = bmp.GetPixel(x,y+i);
             if(c==Color.Black) b = b | (1 << (7-i));
          }
          PrintByte(b);
       }
   }
}


Short explanation: scanning is done from top to bottom, each line is composed of 8 vertical pixel. All is done with the "ESC K" printer command, that enables you to define and print a single line raster bit image on a single text line. From the printer manual:

• n1 and n2 define the number of bytes that comprise the image.
• The image consists of 256*n2+n1 bytes of data, each byte representing a single vertical column of
4/30".
• Images are printed left to right.
• Images are printed at a horizontal resolution of 60 dots per inch and at an approximate vertical resolution of 72 dots per inch.
• Each byte represents a vertical column of eight dots, the most significant bit representing the dot at the top. Simply set a bit to 1 if you want a dot to appear in that position, and to 0 if you want white space to appear.


As said above, I have not tested the code on a real printer so I won't be surprised if it doesn't work at first try.
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma17-Aug-11 0:06
Zil-e-Huma17-Aug-11 0:06 
GeneralRe: Line Printer Class problem Pin
Antonino Porcino17-Aug-11 1:50
Antonino Porcino17-Aug-11 1:50 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma17-Aug-11 4:56
Zil-e-Huma17-Aug-11 4:56 
GeneralRe: Line Printer Class problem Pin
Antonino Porcino17-Aug-11 5:32
Antonino Porcino17-Aug-11 5:32 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma17-Aug-11 18:18
Zil-e-Huma17-Aug-11 18:18 
GeneralRe: Line Printer Class problem Pin
Antonino Porcino17-Aug-11 22:26
Antonino Porcino17-Aug-11 22:26 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma17-Aug-11 23:04
Zil-e-Huma17-Aug-11 23:04 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma17-Aug-11 23:32
Zil-e-Huma17-Aug-11 23:32 
GeneralRe: Line Printer Class problem Pin
Antonino Porcino18-Aug-11 0:09
Antonino Porcino18-Aug-11 0:09 
GeneralRe: Line Printer Class problem Pin
Zil-e-Huma17-Aug-11 22:13
Zil-e-Huma17-Aug-11 22:13 
Questionprint image ? Pin
Herman_6-Aug-11 5:06
Herman_6-Aug-11 5:06 
GeneralPrint UniCode characters and other font size Pin
unodei24-Sep-10 19:58
unodei24-Sep-10 19:58 
GeneralRe: Print UniCode characters and other font size Pin
Antonino Porcino24-Sep-10 23:45
Antonino Porcino24-Sep-10 23:45 
GeneralRe: Print UniCode characters and other font size Pin
unodei25-Sep-10 2:32
unodei25-Sep-10 2:32 
GeneralRe: Print UniCode characters and other font size Pin
Antonino Porcino25-Sep-10 7:18
Antonino Porcino25-Sep-10 7:18 
GeneralRe: Print UniCode characters and other font size Pin
unodei26-Sep-10 14:31
unodei26-Sep-10 14:31 
GeneralRe: Print UniCode characters and other font size Pin
unodei26-Sep-10 14:34
unodei26-Sep-10 14:34 

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