Visual FoxPro Requires Chilkat v11.7.0+

Get the Modules of a QR Code (Bit Matrix)

See more QR Code Examples

Demonstrates getting the QR code itself, as a grid of dark and light modules, to draw with something other than the built-in PNG and SVG output: on a canvas, in a PDF, on a display, or with a label printer language. With output.includeModuleData the response has symbols[0].moduleData, a bit matrix with one bit per module, each row starting on a new byte, most significant bit first, 1 for dark. The quiet zone is not part of the matrix. The example prints the symbol using two characters per module. Visual FoxPro

LOCAL lnSuccess
LOCAL loJson
LOCAL loFmt
LOCAL loJsonOut
LOCAL lnWidth
LOCAL lnHeight
LOCAL lnRowBytes
LOCAL loBd
LOCAL loSbRow
LOCAL lnRow
LOCAL lnCol
LOCAL b
LOCAL lnMask

lnSuccess = 0

*  This example requires the Chilkat API to have been previously unlocked.
*  See Global Unlock Sample for sample code.

loJson = CreateObject('Chilkat.JsonObject')
loJson.UpdateString("payload.text","CHILKAT")
loJson.UpdateBool("output.includeModuleData",1)

loFmt = CreateObject('Chilkat.Formats')
loJsonOut = CreateObject('Chilkat.JsonObject')
lnSuccess = loFmt.QrCode("generate",loJson,loJsonOut)
IF (lnSuccess = 0) THEN
    ? loFmt.LastErrorText
    RELEASE loJson
    RELEASE loFmt
    RELEASE loJsonOut
    CANCEL
ENDIF

lnWidth = loJsonOut.IntOf("symbols[0].moduleData.width")
lnHeight = loJsonOut.IntOf("symbols[0].moduleData.height")
lnRowBytes = loJsonOut.IntOf("symbols[0].moduleData.rowBytes")
? "kind: " + loJsonOut.StringOf("symbols[0].moduleData.kind")
? "modules: " + STR(lnWidth) + " x " + STR(lnHeight) + ", " + STR(lnRowBytes) + " bytes per row"

*  The matrix is height rows of rowBytes bytes.
loBd = CreateObject('Chilkat.BinData')
lnSuccess = loBd.AppendEncoded(loJsonOut.StringOf("symbols[0].moduleData.bytesBase64"),"base64")
IF (lnSuccess = 0) THEN
    ? loBd.LastErrorText
    RELEASE loJson
    RELEASE loFmt
    RELEASE loJsonOut
    RELEASE loBd
    CANCEL
ENDIF

loSbRow = CreateObject('Chilkat.StringBuilder')

lnMask = 128
FOR lnRow = 0 TO lnHeight - 1
    loSbRow.Clear()
    FOR lnCol = 0 TO lnWidth - 1
        *  The module at (col,row) is a bit of the byte at (row * rowBytes) + (col / 8).
        *  The leftmost module of each byte is its most significant bit.
        IF ((lnCol % 8) = 0) THEN
            lnMask = 128
        ENDIF

        b = loBd.GetByte((lnRow * lnRowBytes) + (lnCol / 8))
        IF (((b / lnMask) % 2) = 1) THEN
            loSbRow.Append("##")
        ELSE
            loSbRow.Append("  ")
        ENDIF

        lnMask = lnMask / 2
    NEXT
    ? loSbRow.GetAsString()
NEXT

*  The same symbol as the PNG that the call also returned:

*  

*  Sample output:

*  kind: bitMatrix
*  modules: 21 x 21, 3 bytes per row
*  ##############              ##############
*  ##          ##      ####    ##          ##
*  ##  ######  ##  ##  ####    ##  ######  ##
*  ##  ######  ##  ##          ##  ######  ##
*  ##  ######  ##  ##  ##  ##  ##  ######  ##
*  ##          ##  ####  ##    ##          ##
*  ##############  ##  ##  ##  ##############
*                  ####
*  ##  ##########      ####    ##########
*      ####          ##  ########    ######
*  ####  ########    ####  ##  ####      ####
*        ##  ##      ############    ####  ##
*    ######  ####  ######  ##    ##  ##
*                  ##  ##  ##    ##  ##    ##
*  ##############        ##  ##    ##      ##
*  ##          ##  ##  ##        ######  ####
*  ##  ######  ##  ####  ##  ##    ##
*  ##  ######  ##  ##  ############    ##
*  ##  ######  ##  ##      ##  ####  ##
*  ##          ##    ##  ########          ##
*  ##############  ##      ##      ######

RELEASE loJson
RELEASE loFmt
RELEASE loJsonOut
RELEASE loBd
RELEASE loSbRow