How to print QR Code on ESC/POS Printer by using Delphi? - delphi

Question

this is a test code for printing on EPSON Thermal Printer.
All is working fine except the QR code part.
Printer just get stuck and I need to reset it manually.
I am following the documentation from this page: https://reference.epson-biz.com/modules/ref_escpos/index.php?content_id=143
I am using Delphi 10.3.
What am I doing wrong?
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls ,
Vcl.Printers,
WinProcs, WinTypes;
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
procedure setupPrinter(const printerName: string);
procedure PrintTest;
function DirectToPrinter(S: AnsiString; NextLine: Boolean): Boolean;
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
type
TPrnBuffRec = packed record
bufflength: Word;
Buff_1: array[0..255] of AnsiChar;
end;
function tform1.DirectToPrinter(S: AnsiString; NextLine: Boolean): Boolean;
var
Buff: TPrnBuffRec;
TestInt: Integer;
i: integer;
Device: PChar;
Driver: PChar;
Port: PChar;
begin
TestInt := PassThrough;
if Escape(Printer.Handle, QUERYESCSUPPORT, SizeOf(TESTINT), #testint, nil) > 0 then
begin
if NextLine then S := S + #13 + #10;
StrPCopy(Buff.Buff_1, S);
Buff.bufflength := StrLen(Buff.Buff_1);
Escape(Printer.Canvas.Handle, Passthrough, 0, #buff, nil);
Result := True;
end
else
Result := False;
end;
Procedure tform1.PrintTest;
var
store_len: integer;
store_pl: Byte;
store_ph : Byte;
qrData: string;
Begin
setupPrinter('EPSON TM-T88V Receipt');
Printer.BeginDoc;
DirectToPrinter(Chr(27)+Chr(64), false); //init
DirectToPrinter(Chr(27)+chr(97)+chr(49), false);
// DirectToPrinter(Chr(27)+chr(33)+Chr(8), false); //font select
DirectToPrinter(Chr(27)+chr(45)+Chr(49), false); //underline
DirectToPrinter('Test!', true);
DirectToPrinter(Chr(27)+chr(100)+Chr(5), false); //feed 5 lines
DirectToPrinter(Chr(27)+chr(45)+Chr(48), false); //underline
DirectToPrinter(Chr(27)+chr(97)+chr(48), false); //align-center
DirectToPrinter('Hello world!', true);
DirectToPrinter(
chr(29)+chr(72)+chr(49),
False
); //show content aboce barcode
//
DirectToPrinter(
chr(29)+chr(102)+chr(48),
False
); //font A
// DirectToPrinter(
// chr(29)+chr(104)+chr(50),
// False
//
// ); //height
// DirectToPrinter(
// chr(29)+chr(119)+chr(50),
// False
//
// ); //width
DirectToPrinter(
chr(29)+chr(107)+chr(4)+'*0001443AB*',
true
); //ean 39
DirectToPrinter(
chr(29)+chr(107)+chr(73)+chr(13)+chr(123)+Chr(65)+'8600123456789',
true
); // ean 128
DirectToPrinter(
chr(29)+chr(107)+chr(67)+Chr(12)+'860012345678',
true
); // ean 13
//*************************QR CODE ****************/
qrData := 'https://www.stackoverflow.com';
store_len:= Length(qrData)+3;
store_pl := store_len mod 256;
store_ph := Trunc(store_len / 256);
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+char(3)+chr(0)+Chr(49)+Chr(65)+
Chr(49)+Chr(0),false
); //QR Code: Select the model
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+chr(3)+Chr(0)+Chr(49)+Chr(67)+
Chr(2),false
); //QR Code: Set the size of module
//QR Code: Select the error correction level
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+chr(3)+Chr(0)+Chr(49)+Chr(69)+
Chr(48),false
);
//QR Code: Store the data in the symbol storage area
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+
chr(store_pl)+Chr(store_ph)+
Chr(49)+Chr(80)+Chr(48)+qrData,
false
);
// QR Code: Print the symbol data in the symbol storage area
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+chr(store_pl)+chr(store_ph)+Chr(49)+Chr(81)+Chr(48),true
);
DirectToPrinter(Chr(27)+Chr(112)+Chr(48)+Chr(60)+Chr(120), false); //drawer pulse
Printer.EndDoc;
End;
procedure TForm1.setupPrinter(const printerName: string);
var
Buff: TPrnBuffRec;
TestInt: Integer;
i: integer;
Device: PChar;
Driver: PChar;
Port: PChar;
HDeviceMode: THandle;
begin
Printer.PrinterIndex := -1;
GetMem(Device, 255);
GetMem(Driver, 255);
GetMem(Port, 255);
for I := 0 to Printer.Printers.Count - 1 do
begin
if Printer.Printers[I] = printername then
begin
printer.PrinterIndex := I;
printer.getprinter(Device, Driver, Port, HdeviceMode);
StrCat(Device, ',');
StrCat(Device, Driver);
StrCat(Device, Port);
WriteProfileString('windows', 'device', Device);
StrCopy(Device, 'windows');
SendMessage(HWND_BROADCAST, WM_WININICHANGE,
0, Longint(#Device));
break;
end;
end;
FreeMem(Device, 255);
FreeMem(Driver, 255);
FreeMem(Port, 255);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
PrintTest;
end;
end.

Answer 1

The length is specified incorrectly in the command to print the QR code.
The same data length as the command that stores the QR code, which is the previous command, is specified, but this is a fixed value of 3 bytes.
GS ( k <Function 181>
This part:
// QR Code: Print the symbol data in the symbol storage area
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+chr(store_pl)+chr(store_ph)+Chr(49)+Chr(81)+Chr(48),true
);
Please change to here:
// QR Code: Print the symbol data in the symbol storage area
DirectToPrinter(
Chr(29)+chr(40)+Chr(107)+chr(3)+chr(0)+Chr(49)+Chr(81)+Chr(48),true
);

Answer 2

You have a problem with function 165: QR Code: Select the model
You put: Chr(29)+chr(40)+Chr(107)+char(3)+chr(0)+Chr(49).....
And is: Chr(29)+chr(40)+Chr(107)+chr(4)+chr(0)+Chr(49).....