Delphi ActiveX Requires Chilkat v11.7.0+

Handle QR Code Errors

See more QR Code Examples

Demonstrates what happens when a request is refused. QrCode returns false and the response holds errors[0] with three members: a code that does not change between versions, the path of the request member at fault (a JSON Pointer such as /encoding/qr/version), and a message. Requests are checked strictly, so a misspelled option is an error rather than being silently ignored. LastErrorText has the same information in more detail. Delphi ActiveX

var
success: Integer;
fmt: TChilkatFormats;
json: TChilkatJsonObject;
jsonOut: TChilkatJsonObject;

begin
success := 0;

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

fmt := TChilkatFormats.Create(Self);
json := TChilkatJsonObject.Create(Self);
jsonOut := TChilkatJsonObject.Create(Self);

//  1. A misspelled option: "moduleSise" for "moduleSize".
json.UpdateString('payload.text','https://www.chilkatsoft.com/');
json.UpdateInt('render.moduleSise',8);
success := fmt.QrCode('generate',json.ControlInterface,jsonOut.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add('code: ' + jsonOut.StringOf('errors[0].code'));
    Memo1.Lines.Add('path: ' + jsonOut.StringOf('errors[0].path'));
    Memo1.Lines.Add('message: ' + jsonOut.StringOf('errors[0].message'));
  end;

//  2. A value out of range: QR versions are 1 to 40.
json.Clear();
json.UpdateString('payload.text','https://www.chilkatsoft.com/');
json.UpdateInt('encoding.qr.version',41);
success := fmt.QrCode('generate',json.ControlInterface,jsonOut.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add('code: ' + jsonOut.StringOf('errors[0].code'));
    Memo1.Lines.Add('path: ' + jsonOut.StringOf('errors[0].path'));
    Memo1.Lines.Add('message: ' + jsonOut.StringOf('errors[0].message'));
  end;

//  3. Too much data: this text does not fit a version 1 symbol.
json.Clear();
json.UpdateString('payload.text','https://www.chilkatsoft.com/barcode_overview.asp');
json.UpdateInt('encoding.qr.version',1);
success := fmt.QrCode('generate',json.ControlInterface,jsonOut.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add('code: ' + jsonOut.StringOf('errors[0].code'));
    Memo1.Lines.Add('path: ' + jsonOut.StringOf('errors[0].path'));
    Memo1.Lines.Add('message: ' + jsonOut.StringOf('errors[0].message'));
  end;

//  A program can act on the code.
if (jsonOut.StringOf('errors[0].code') = 'capacityExceeded') then
  begin
    Memo1.Lines.Add('The text is too long for the symbol size allowed.');
  end;

//  Sample output:

//  code: unknownOption
//  path: /render/moduleSise
//  message: unknown option
//  code: outOfRange
//  path: /encoding/qr/version
//  message: the value is out of range
//  code: capacityExceeded
//  path: /payload
//  message: the payload does not fit the requested QR version at the requested error-correction level
//  The text is too long for the symbol size allowed.