Library file presented is Barcode.h under Lib directory, which contains inline C++ code for

• Code39
• Code93
• CodeI2of5
• Code128A
• Code128B
• Code128C

1. Encode...()
2. Draw...(...)

Call default constructor first, then call following 2 functions:
BOOL Encode39(const char*pszCodeIn);
void Draw39(HDC hDC,int iX,int iY0,int iY1,const COLORREF clrBar,const COLORREF clrSpace,const int iPenW);

pszCodeIn: string to be encoded, i.e. "1234567890"
iX: start horizontal position to draw the barcode
iY0,iY1: start and end vertical positions to draw the barcode
clrBar, clrSpace: colors of bar and space
iPenW: width of pen to draw the barcode

A byte array is defined in BarcodeBase class as BYTE ia_Buf[4096];
Each byte of the array represents a bar or space, bits of the byte are encoded in the format:
[n/a][n/a][n/a][n/a][n/a][n/a][w-n][b-s]
First 6 bits are not used.
Last bit is flagged for bar or space.
Last second bit is flagged for wide or narrow.
So, value of the byte means
0x00 = a narrow space
0x01 = a narrow bar
0x02 = a wide space
0x03 = a wide bar Note:

class BarcodeEan13 is special: Last third bit is used by the class to indicate if the bar (space) is longer than others.

Sample program:

The sample is a dialog based MFC program.
Main dialog is in borderless style, when edit-box Move (refer to picture bellow) gets focus, user can use arrow keys of up, down, left and right to move main dialog.
This feature allows you to compare barcode drawn on main dialog with other barcode programs easily.
You also can use mouse to drag main dialog by clicking on it as clicking on caption of normal windows.

Controls:

• Buttons:
  OnTop/OnNormal: set the program as top-most-window or not
  Close: close the program
  Help: display this html file
  Print: print barcode
• Others
  Style: barcode styles or symbologies
  Map: map-mode used
  Move: move main dialog by arrow keys once it gets focus
  Code: string to be encoded
  X,Y,Height: for print positions, unit is in logic points.
  Pen width: width of one bar or space

Please note: 

Some MapModes (such as MM_HIENGLISH) can not be displayed properly on screen, you have to test them by printing.

Disappoint:

This sample and library file are my test program for barcode, which doesn't include second part: dynamical bitmap of barcode generated from encoding.

Why do I test barcode with bitmap? Here is answer:
As we know, there are three methods for printing:

1. By drawing 
   Such as LineTo()
2. By Bitmap
   Such as BitBlt()
3. By fonts
   Such as TextOut()

Barcode must be printed clearly with high qualities. The only way to print good barcode is by fonts. 
If you try to use the code for commercial purposes, result is very disappointed because this program dese not use fonts.