二维码相关内容收集

1、zbar 读取

http://zbar.sourceforge.net/download.html

ZBar is an open source software suite for reading bar codes      from various sources, such as video streams, image files and raw      intensity sensors.  It supports many popular symbologies      (types of bar codes) including EAN-13/UPC-A, UPC-E, EAN-8, Code      128, Code 39, Interleaved 2 of 5 and QR Code.

2、ZxingQrcode

http://zarko-gajic.iz.hr/firemonkey-mobile-android-ios-qr-code-generation-using-delphi-xe-5-delphizxingqrcode/

In the VCL, the TCanvas class allows accessing single pixels through the “Canvas.Pixels()” property. In FireMonkey this is not supported and you have to use the SetPixel property of a TBitmapData instance.

Once the qr code is generated, to convert it to a bitmap image, in FireMonkey:

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var   QRCode: TDelphiZXingQRCode;   Row, Column: Integer;   pixelColor : TAlphaColor;   vBitMapData : TBitmapData;   rSrc, rDest : TRectF;   s : widestring; begin   QRCode := TDelphiZXingQRCode.Create;   try     QRCode.Data := edtText.Text;     QRCode.Encoding := TQRCodeEncoding(cmbEncoding.ItemIndex);     QRCode.QuietZone := StrToIntDef(edtQuietZone.Text, 4);     QRCodeBitmap.SetSize(QRCode.Rows, QRCode.Columns);     for Row := 0 to QRCode.Rows - 1 do     begin       for Column := 0 to QRCode.Columns - 1 do       begin         if (QRCode.IsBlack[Row, Column]) then           pixelColor := TAlphaColors.Black         else           pixelColor := TAlphaColors.White;           if QRCodeBitmap.Map(TMapAccess.maWrite, vBitMapData)  then         try           vBitMapData.SetPixel(Column, Row, pixelColor);         finally           QRCodeBitmap.Unmap(vBitMapData);         end;       end;     end;   finally     QRCode.Free;   end;     //refresh image control imgQRCode is a TImage   {code below} end;

Note: compare this with the VCL approach of TDelphiZXingQRCode usage.

 

VCL’s Canvas.StretchDraw to FMX’s Canvas.DrawBitmap

There’s no StrecthDraw in FMX’s Canvas class. There’s DrawBitmap. StretchDraw by default does no antialiasing. FMX does. So I had to play a little until I was able to make it work correctly.

I’ve decided to use TImage and not TPaintBox as I was simply not able to make TPictureBox in FireMonkey draw what I wanted

Using TImage, the code to get/display the generated QR Code is as follows:

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//refresh image. imgQRCode is a TImage   imgQRCode.Bitmap.SetSize(QRCodeBitmap.Width, QRCodeBitmap.Height);   rSrc := TRectF.Create(0, 0, QRCodeBitmap.Width, QRCodeBitmap.Height); rDest := TRectF.Create(0, 0, imgQRCode.Bitmap.Width, imgQRCode.Bitmap.Height);   if imgQRCode.Bitmap.Canvas.BeginScene then try   imgQRCode.Bitmap.Canvas.Clear(TAlphaColors.White);     imgQRCode.Bitmap.Canvas.DrawBitmap(QRCodeBitmap, rSrc, rDest, 1); finally   imgQRCode.Bitmap.Canvas.EndScene; end;

Aliasing – Do Not Need It!

By default, in FMX, when using DrawBitmap to resize it, antialiasing is used by default. There are two properties you need to set to ensure a bigger copy of your (small) qr code is drawn pixel-copy-perfect.

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begin   imgQRCode.DisableInterpolation := true;   imgQRCode.WrapMode := TImageWrapMode.iwStretch; end;

In a FireMonkey Desktop application, this works as expected.

On FireMonkey Mobile it does not   – the resized image is still blurred (antialiasing used).

That’s it. QR Codes generation in FireMonkey – both desktop and mobile!

Download the FMX version of DelphiZXIngQRCode.pas: FMX-DelphiZXIngQRCode

Comments are welcome (even more if you know how to resize a bitmap in FireMonkey on mobile without antialiasing)!

 

相关链接：  http://zarko-gajic.iz.hr/generating-qr-codes-using-delphi-delphizxingqrcode-open-source-unit-by-debenu/