Barcode Generation (FWER_BarCode)

Fuente: source/classes/fwbarcod.prg, source/function/fwzebra.prg

FWER_BarCode is FiveWin's built-in barcode rendering engine. It supports 17 barcode symbologies through a native GDI engine, with optional fallback to the hbzebra library for 2D codes (QR, DataMatrix, PDF417). Barcodes can be rendered on windows, dialogs, printers, and PDF output.

Symbology Reference

nBCodeType	Symbology	Description
1	Code 39	Standard Code 39 (3-of-9) alphanumeric
2	Code 39 + check	Code 39 with mandatory check digit
3	Code 128 auto	Code 128 with automatic mode selection (A/B/C)
4	Code 128 A	Code 128 mode A (uppercase, control chars)
5	Code 128 B	Code 128 mode B (full ASCII)
6	Code 128 C	Code 128 mode C (numeric pairs, highest density)
7	EAN-8	EAN-8 (8-digit product code)
8	EAN-13	EAN-13 (13-digit product code, most common retail)
9	UPC-A	UPC-A (12-digit US product code)
10	Codabar	Codabar (libraries, blood banks, FedEx)
11	Supplement 5	5-digit supplement for EAN/UPC
12	Industrial 2 of 5	Industrial 2 of 5 numeric
13	Industrial 2 of 5 + check	Industrial 2 of 5 with check digit
14	Interleaved 2 of 5	Interleaved 2 of 5 (high-density numeric)
15	Interleaved 2 of 5 + check	Interleaved 2 of 5 with check digit
16	Matrix 2 of 5	Matrix 2 of 5 numeric
17	Matrix 2 of 5 + check	Matrix 2 of 5 with check digit

DATA Members

DATA	Default	Description
`hDC`	--	Device context handle (window, dialog, printer)
`cText`	`""`	Barcode text to encode
`nTop, nLeft`	--	Position coordinates
`nWidth, nHeight`	200, 20	Barcode dimensions
`nColText`	0 (black)	Bar (pin) color
`nColPane`	RGB(255,255,255)	Background color
`lHorizontal`	.T.	Horizontal (.T.) or vertical (.F.) orientation
`lTransparent`	.F.	Transparent background
`nPinWidth`	--	Individual bar (pin) width in pixels

Methods

Method	Description
`New( hDC, cText, nTop, nLeft, nW, nH, nType, nClrT, nClrP, lHorz, lTransp, nPinW, nFlags, lPrinter )`	Create a barcode object. Accepts numeric type (1-17) or string alias ("EAN13", "128", "39", etc.)
`ShowBarcode()`	Render the barcode to the device context using the configured parameters
`CreateBarcode( cCode )`	Generate the bar pattern string for a given code
`CheckDigit()`	Compute and append the appropriate check digit for the current symbology

Free Funciones

FW_SayBarCode()

Direct barcode rendering without creating an object instance:

FW_SayBarCode( oWnd, cText, aRect, cType, nClrT, nClrB, lVert, lTransp )

Parameters: oWnd (window/dialog/printer), cText (data to encode), aRect (array { nTop, nLeft, nBottom, nRight }), cType (symbology string), nClrT/nClrB (fore/back colors), lVert (vertical orientation), lTransp (transparent background).

FW_BarCodeBmp()

Generates a standalone bitmap handle of the barcode for use in reports or image controls.

Example: EAN-13 on Printer

#include "FiveWin.ch"

FUNCTION PrintBarcode()
   LOCAL oPrn, nRow := 2.0  // cm from top

   PRINT oPrn NAME "Barcode Test"
   PAGE
      oPrn:Say( nRow, 1.0, "Product Barcode:" )
      nRow += 0.8

      // Method 1: Using FWER_BarCode directly
      FWER_BarCode():New( oPrn:hDC, "5901234567890", ;
                          oPrn:CmToPix( nRow ),        // nTop
                          oPrn:CmToPix( 1.0 ),         // nLeft
                          oPrn:CmToPix( 5.0 ),         // nWidth
                          oPrn:CmToPix( 2.5 ),         // nHeight
                          8, 0, 16777215, .T., .F. ):ShowBarcode()

      // Method 2: Using FW_SayBarCode convenience function
      nRow += 3.0
      FW_SayBarCode( oPrn, "5901234567890", ;
                     { oPrn:CmToPix( nRow ), oPrn:CmToPix( 1.0 ), ;
                       oPrn:CmToPix( nRow + 2.5 ), oPrn:CmToPix( 6.0 ) }, ;
                     "EAN13", 0, 16777215 )
   ENDPAGE
   ENDPRINT
RETURN NIL

Notes

String type names are case-insensitive and normalized by removing "CODE" prefix, spaces, underscores, and hyphens. Example: "CODE128", "code 128", and "128" all resolve to Code 128 auto.
When the hbzebra library is linked, 2D symbologies (QR, DataMatrix, PDF417) are automatically routed through the Zebra engine, which also supports direct PDF output via TPDF object detection.
Use FWER_BarCode:lUseZebraLib := .T. at class level to force the Zebra engine for all supported symbologies.
Printer output uses GDI FillRect for bars and FillRectEx for background, ensuring correct scaling on high-DPI devices.