Open Source QRCode Library

mengwangk

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20 Sep 2007CPOL1 min read

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How to use QRCode library to encode and decode QRCode

Download source - 2.35 MB

Introduction

In this article, I will briefly describe the functionalities of the QRCode library.

Background

QRCode library is a .NET component that can be used to encode and decode QRCode. QRCode is a 2 dimensional bar code that originated in Japan. Nowadays, it is widely used in a wide range of industries, e.g. for vehicle parts tracking and inventory management.

QR stands for "Quick Response". It was created by the Japanese corporation Denso-Wave in 1994 and is aimed at decoding contents at high speed. Nowadays, QR Code is used in mobile phones to ease data entry.

QRCode can also be printed on a business card or shown on any display, which can then be captured by the mobile phone provided the mobile phone has the software to read QRCode.

QRCode library provides functions to:

Encode content into a QR Code image which can be saved in JPEG, GIF, PNG, or Bitmap formats
Decode a QR Code image

Using the Code

The library can be used in any .NET 2.0 Windows Application, ASP.NET Web application or Windows Mobile device application.

Some sample screenshots are displayed below:

QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
          String encoding = cboEncoding.Text ;
          if (encoding == "Byte") {
              qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
          } else if (encoding == "AlphaNumeric") {
              qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.ALPHA_NUMERIC;
          } else if (encoding == "Numeric") {
              qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.NUMERIC;
          }
          try {
              int scale = Convert.ToInt16(txtSize.Text);
              qrCodeEncoder.QRCodeScale = scale;
          } catch (Exception ex) {
              MessageBox.Show("Invalid size!");
              return;
          }
          try {
              int version = Convert.ToInt16(cboVersion.Text) ;
              qrCodeEncoder.QRCodeVersion = version;
          } catch (Exception ex) {
              MessageBox.Show("Invalid version !");
          }

          string errorCorrect = cboCorrectionLevel.Text;
          if (errorCorrect == "L")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.L;
          else if (errorCorrect == "M")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
          else if (errorCorrect == "Q")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.Q;
          else if (errorCorrect == "H")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.H;

          Image image;
          String data = txtEncodeData.Text;
          image = qrCodeEncoder.Encode(data);
          picEncode.Image = image;

History

20^th September, 2007: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

mengwangk

Software Developer (Senior)

Malaysia

A programmer for a long time, and still learning everyday.

A supporter for open source solutions, and have written quite a few open source software both in .NET and Java.

https://mengwangk.github.io/

public virtual Bitmap Encode(String content, Encoding encoding) { bool[][] matrix = calQrcode(encoding.GetBytes(content)); SolidBrush brush = new SolidBrush(qrCodeBackgroundColor); // white pixels plus 1 pixel for border int pixelesBlancos = (qrCodeScale * 4) + 1; // add the white pixels to the width and height Bitmap image = new Bitmap((matrix.Length * qrCodeScale) + (pixelesBlancos * 2), (matrix.Length * qrCodeScale) + (pixelesBlancos * 2)); Graphics g = Graphics.FromImage(image); g.FillRectangle(brush, new Rectangle(0, 0, image.Width, image.Height)); // Draw border g.DrawRectangle(new Pen(new SolidBrush(qrCodeForegroundColor)), new Rectangle(0, 0, image.Width - 1, image.Height - 1)); brush.Color = qrCodeForegroundColor ; for (int i = 0; i < matrix.Length ; i++) { for (int j = 0; j < matrix.Length ; j++) { if (matrix[j][i]) { // Draw code beyond the white space and border g.FillRectangle(brush, j * qrCodeScale + pixelesBlancos, i * qrCodeScale + pixelesBlancos, qrCodeScale, qrCodeScale); } } } return image; }

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