Delphi DLL 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. Delphi DLL

var
success: Boolean;
json: HCkJsonObject;
fmt: HCkFormats;
jsonOut: HCkJsonObject;
width: Integer;
height: Integer;
rowBytes: Integer;
bd: HCkBinData;
sbRow: HCkStringBuilder;
row: Integer;
col: Integer;
b: Integer;
mask: Integer;

begin
success := False;

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

json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'payload.text','CHILKAT');
CkJsonObject_UpdateBool(json,'output.includeModuleData',True);

fmt := CkFormats_Create();
jsonOut := CkJsonObject_Create();
success := CkFormats_QrCode(fmt,'generate',json,jsonOut);
if (success = False) then
  begin
    Memo1.Lines.Add(CkFormats__lastErrorText(fmt));
    Exit;
  end;

width := CkJsonObject_IntOf(jsonOut,'symbols[0].moduleData.width');
height := CkJsonObject_IntOf(jsonOut,'symbols[0].moduleData.height');
rowBytes := CkJsonObject_IntOf(jsonOut,'symbols[0].moduleData.rowBytes');
Memo1.Lines.Add('kind: ' + CkJsonObject__stringOf(jsonOut,'symbols[0].moduleData.kind'));
Memo1.Lines.Add('modules: ' + IntToStr(width) + ' x ' + IntToStr(height) + ', ' + IntToStr(rowBytes) + ' bytes per row');

//  The matrix is height rows of rowBytes bytes.
bd := CkBinData_Create();
success := CkBinData_AppendEncoded(bd,CkJsonObject__stringOf(jsonOut,'symbols[0].moduleData.bytesBase64'),'base64');
if (success = False) then
  begin
    Memo1.Lines.Add(CkBinData__lastErrorText(bd));
    Exit;
  end;

sbRow := CkStringBuilder_Create();

mask := 128;
for row := 0 to height - 1 do
  begin
    CkStringBuilder_Clear(sbRow);
    for col := 0 to width - 1 do
      begin
        //  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 mod 8) = 0) then
          begin
            mask := 128;
          end;
        b := CkBinData_GetByte(bd,(row * rowBytes) + (col / 8));
        if (((b / mask) mod 2) = 1) then
          begin
            CkStringBuilder_Append(sbRow,'##');
          end
        else
          begin
            CkStringBuilder_Append(sbRow,'  ');
          end;
        mask := mask / 2;
      end;

    Memo1.Lines.Add(CkStringBuilder__getAsString(sbRow));
  end;

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

//  

//  Sample output:

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

CkJsonObject_Dispose(json);
CkFormats_Dispose(fmt);
CkJsonObject_Dispose(jsonOut);
CkBinData_Dispose(bd);
CkStringBuilder_Dispose(sbRow);