unit Main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls, Mask, ExtDlgs;

type
  TFrmMain = class(TForm)
    BtnGenerate: TButton;
    Image1: TImage;
    MemoData: TMemo;
    Label1: TLabel;
    EditWidth: TMaskEdit;
    Label2: TLabel;
    EditHeight: TMaskEdit;
    ComboBoxErrCorrLevel: TComboBox;
    Label3: TLabel;
    procedure BtnGenerateClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  FrmMain: TFrmMain;

implementation

uses
 PngImage,
 HTTPApp,
 WinInet;

{$R *.dfm}
type
TQrImage_ErrCorrLevel=(L,M,Q,H);

const
UrlGoogleQrCode='http://chart.apis.google.com/chart?chs=%dx%d&cht=qr&chld=%s&chl=%s';
QrImgCorrStr   : array [TQrImage_ErrCorrLevel] of string=('L','M','Q','H');


procedure WinInet_HttpGet(const Url: string;Stream:TStream);
const
BuffSize = 1024*1024;
var
  hInter   : HINTERNET;
  UrlHandle: HINTERNET;
  BytesRead: DWORD;
  Buffer   : Pointer;
begin
  hInter := InternetOpen('', INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);
  if Assigned(hInter) then
  begin
    Stream.Seek(0,0);
    GetMem(Buffer,BuffSize);
    try
        UrlHandle := InternetOpenUrl(hInter, PChar(Url), nil, 0, INTERNET_FLAG_RELOAD, 0);
        if Assigned(UrlHandle) then
        begin
          repeat
            InternetReadFile(UrlHandle, Buffer, BuffSize, BytesRead);
            if BytesRead>0 then
             Stream.WriteBuffer(Buffer^,BytesRead);
          until BytesRead = 0;
          InternetCloseHandle(UrlHandle);
        end;
    finally
      FreeMem(Buffer);
    end;
    InternetCloseHandle(hInter);
  end
end;

procedure GetQrCode(Width,Height:Word;Correction_Level:TQrImage_ErrCorrLevel;const Data:string;StreamImage : TMemoryStream);
Var
 EncodedURL  : string;
begin
  EncodedURL:=Format(UrlGoogleQrCode,[Width,Height,QrImgCorrStr[Correction_Level],HTTPEncode(Data)]);
  WinInet_HttpGet(EncodedURL,StreamImage);
end;


procedure TFrmMain.BtnGenerateClick(Sender: TObject);
var
ImageStream : TMemoryStream;
PngImage    : TPngImage;
begin
 Image1.Picture:=nil;
 ImageStream:=TMemoryStream.Create;
 PngImage   :=TPngImage.Create;
 try
   try
       GetQrCode(StrToInt(Trim(EditWidth.Text)),StrToInt(Trim(EditHeight.Text)),TQrImage_ErrCorrLevel(ComboBoxErrCorrLevel.ItemIndex),MemoData.Lines.Text,ImageStream);
       if ImageStream.Size>0 then
       begin
          ImageStream.Position:=0;
          PngImage.LoadFromStream(ImageStream);
          Image1.Picture.Assign(PngImage);
       end;
   except
      on E: exception do
      ShowMessage(E.Message);
   end;
 finally
  ImageStream.Free;
  PngImage.Free;
 end;
end;

procedure TFrmMain.FormCreate(Sender: TObject);
begin
    BtnGenerateClick(Sender);
end;

end.