Go 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. Go

    success := false

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

    json := chilkat.NewJsonObject()
    json.UpdateString("payload.text","CHILKAT")
    json.UpdateBool("output.includeModuleData",true)

    fmt := chilkat.NewFormats()
    jsonOut := chilkat.NewJsonObject()
    success = fmt.QrCode("generate",json,jsonOut)
    if success == false {
        fmt.Println(fmt.LastErrorText())
        json.DisposeJsonObject()
        fmt.DisposeFormats()
        jsonOut.DisposeJsonObject()
        return
    }

    width := jsonOut.IntOf("symbols[0].moduleData.width")
    height := jsonOut.IntOf("symbols[0].moduleData.height")
    rowBytes := jsonOut.IntOf("symbols[0].moduleData.rowBytes")
    fmt.Println("kind: ", *jsonOut.StringOf("symbols[0].moduleData.kind"))
    fmt.Println("modules: ", width, " x ", height, ", ", rowBytes, " bytes per row")

    //  The matrix is height rows of rowBytes bytes.
    bd := chilkat.NewBinData()
    success = bd.AppendEncoded(*jsonOut.StringOf("symbols[0].moduleData.bytesBase64"),"base64")
    if success == false {
        fmt.Println(bd.LastErrorText())
        json.DisposeJsonObject()
        fmt.DisposeFormats()
        jsonOut.DisposeJsonObject()
        bd.DisposeBinData()
        return
    }

    sbRow := chilkat.NewStringBuilder()
    var row int
    var col int
    var b int
    mask := 128
    for row = 0; row <= height - 1; row++ {
        sbRow.Clear()
        for col = 0; col <= width - 1; col++ {
            //  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 (col % 8) == 0 {
                mask = 128
            }

            b = bd.GetByte((row * rowBytes) + (col / 8))
            if ((b / mask) % 2) == 1 {
                sbRow.Append("##")
            } else {
                sbRow.Append("  ")
            }

            mask = mask / 2
        }

        fmt.Println(*sbRow.GetAsString())
    }

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

    //  

    //  Sample output:

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

    json.DisposeJsonObject()
    fmt.DisposeFormats()
    jsonOut.DisposeJsonObject()
    bd.DisposeBinData()
    sbRow.DisposeStringBuilder()