zxing/csharp/qrcode/QRCodeReader.cs
srowen d4efd44fb0 New C# port from Suraj Supekar
git-svn-id: https://zxing.googlecode.com/svn/trunk@1202 59b500cc-1b3d-0410-9834-0bbf25fbcc57
2010-02-05 19:52:53 +00:00

180 lines
6.1 KiB
C#
Executable file

/*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using BarcodeFormat = com.google.zxing.BarcodeFormat;
using DecodeHintType = com.google.zxing.DecodeHintType;
using Reader = com.google.zxing.Reader;
using ReaderException = com.google.zxing.ReaderException;
using Result = com.google.zxing.Result;
using ResultPoint = com.google.zxing.ResultPoint;
using ResultMetadataType = com.google.zxing.ResultMetadataType;
using BinaryBitmap = com.google.zxing.BinaryBitmap;
using BitMatrix = com.google.zxing.common.BitMatrix;
using DecoderResult = com.google.zxing.common.DecoderResult;
using DetectorResult = com.google.zxing.common.DetectorResult;
using Decoder = com.google.zxing.qrcode.decoder.Decoder;
using Detector = com.google.zxing.qrcode.detector.Detector;
namespace com.google.zxing.qrcode
{
/// <summary> This implementation can detect and decode QR Codes in an image.
///
/// </summary>
/// <author> Sean Owen
/// </author>
/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
/// </author>
public class QRCodeReader : Reader
{
virtual protected internal Decoder Decoder
{
get
{
return decoder;
}
}
//UPGRADE_NOTE: Final was removed from the declaration of 'NO_POINTS '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
private static readonly ResultPoint[] NO_POINTS = new ResultPoint[0];
//UPGRADE_NOTE: Final was removed from the declaration of 'decoder '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
private Decoder decoder = new Decoder();
/// <summary> Locates and decodes a QR code in an image.
///
/// </summary>
/// <returns> a String representing the content encoded by the QR code
/// </returns>
/// <throws> ReaderException if a QR code cannot be found, or cannot be decoded </throws>
public virtual Result decode(BinaryBitmap image)
{
return decode(image, null);
}
public virtual Result decode(BinaryBitmap image, System.Collections.Hashtable hints)
{
DecoderResult decoderResult;
ResultPoint[] points;
if (hints != null && hints.ContainsKey(DecodeHintType.PURE_BARCODE))
{
BitMatrix bits = extractPureBits(image.BlackMatrix);
decoderResult = decoder.decode(bits);
points = NO_POINTS;
}
else
{
DetectorResult detectorResult = new Detector(image.BlackMatrix).detect(hints);
decoderResult = decoder.decode(detectorResult.Bits);
points = detectorResult.Points;
}
Result result = new Result(decoderResult.Text, decoderResult.RawBytes, points, BarcodeFormat.QR_CODE);
if (decoderResult.ByteSegments != null)
{
result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, decoderResult.ByteSegments);
}
if (decoderResult.ECLevel != null)
{
result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, decoderResult.ECLevel.ToString());
}
return result;
}
/// <summary> This method detects a barcode in a "pure" image -- that is, pure monochrome image
/// which contains only an unrotated, unskewed, image of a barcode, with some white border
/// around it. This is a specialized method that works exceptionally fast in this special
/// case.
/// </summary>
private static BitMatrix extractPureBits(BitMatrix image)
{
// Now need to determine module size in pixels
int height = image.Height;
int width = image.Width;
int minDimension = System.Math.Min(height, width);
// First, skip white border by tracking diagonally from the top left down and to the right:
int borderWidth = 0;
while (borderWidth < minDimension && !image.get_Renamed(borderWidth, borderWidth))
{
borderWidth++;
}
if (borderWidth == minDimension)
{
throw ReaderException.Instance;
}
// And then keep tracking across the top-left black module to determine module size
int moduleEnd = borderWidth;
while (moduleEnd < minDimension && image.get_Renamed(moduleEnd, moduleEnd))
{
moduleEnd++;
}
if (moduleEnd == minDimension)
{
throw ReaderException.Instance;
}
int moduleSize = moduleEnd - borderWidth;
// And now find where the rightmost black module on the first row ends
int rowEndOfSymbol = width - 1;
while (rowEndOfSymbol >= 0 && !image.get_Renamed(rowEndOfSymbol, borderWidth))
{
rowEndOfSymbol--;
}
if (rowEndOfSymbol < 0)
{
throw ReaderException.Instance;
}
rowEndOfSymbol++;
// Make sure width of barcode is a multiple of module size
if ((rowEndOfSymbol - borderWidth) % moduleSize != 0)
{
throw ReaderException.Instance;
}
int dimension = (rowEndOfSymbol - borderWidth) / moduleSize;
// Push in the "border" by half the module width so that we start
// sampling in the middle of the module. Just in case the image is a
// little off, this will help recover.
borderWidth += (moduleSize >> 1);
int sampleDimension = borderWidth + (dimension - 1) * moduleSize;
if (sampleDimension >= width || sampleDimension >= height)
{
throw ReaderException.Instance;
}
// Now just read off the bits
BitMatrix bits = new BitMatrix(dimension);
for (int i = 0; i < dimension; i++)
{
int iOffset = borderWidth + i * moduleSize;
for (int j = 0; j < dimension; j++)
{
if (image.get_Renamed(borderWidth + j * moduleSize, iOffset))
{
bits.set_Renamed(j, i);
}
}
}
return bits;
}
}
}