Ruby 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. Ruby

require 'chilkat'

success = false

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

json = Chilkat::CkJsonObject.new()
json.UpdateString("payload.text","CHILKAT")
json.UpdateBool("output.includeModuleData",true)

fmt = Chilkat::CkFormats.new()
jsonOut = Chilkat::CkJsonObject.new()
success = fmt.QrCode("generate",json,jsonOut)
if (success == false)
    print fmt.lastErrorText() + "\n";
    exit
end

width = jsonOut.IntOf("symbols[0].moduleData.width")
height = jsonOut.IntOf("symbols[0].moduleData.height")
rowBytes = jsonOut.IntOf("symbols[0].moduleData.rowBytes")
print "kind: " + jsonOut.stringOf("symbols[0].moduleData.kind") + "\n";
print "modules: " + width.to_s() + " x " + height.to_s() + ", " + rowBytes.to_s() + " bytes per row" + "\n";

#  The matrix is height rows of rowBytes bytes.
bd = Chilkat::CkBinData.new()
success = bd.AppendEncoded(jsonOut.stringOf("symbols[0].moduleData.bytesBase64"),"base64")
if (success == false)
    print bd.lastErrorText() + "\n";
    exit
end

sbRow = Chilkat::CkStringBuilder.new()

mask = 128
for row in 0 .. height - 1
    sbRow.Clear()
    for col in 0 .. width - 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 ((col % 8) == 0)
            mask = 128
        end

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

        mask = mask / 2
    end
    print sbRow.getAsString() + "\n";
end

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

#  

#  Sample output:

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