zxing/csharp/qrcode/QRCodeReader.cs
2013-01-18 20:14:03 +00:00

213 lines
7.4 KiB
C#
Executable file

using System;
using System.Collections.Generic;
/*
* 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.
*/
namespace com.google.zxing.qrcode
{
using BarcodeFormat = com.google.zxing.BarcodeFormat;
using BinaryBitmap = com.google.zxing.BinaryBitmap;
using ChecksumException = com.google.zxing.ChecksumException;
using DecodeHintType = com.google.zxing.DecodeHintType;
using FormatException = com.google.zxing.FormatException;
using NotFoundException = com.google.zxing.NotFoundException;
using Reader = com.google.zxing.Reader;
using Result = com.google.zxing.Result;
using ResultMetadataType = com.google.zxing.ResultMetadataType;
using ResultPoint = com.google.zxing.ResultPoint;
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;
/// <summary>
/// This implementation can detect and decode QR Codes in an image.
///
/// @author Sean Owen
/// </summary>
public class QRCodeReader : com.google.zxing.Reader
{
private static readonly ResultPoint[] NO_POINTS = new ResultPoint[0];
private readonly Decoder decoder = new Decoder();
protected internal virtual Decoder Decoder
{
get
{
return decoder;
}
}
/// <summary>
/// Locates and decodes a QR code in an image.
/// </summary>
/// <returns> a String representing the content encoded by the QR code </returns>
/// <exception cref="NotFoundException"> if a QR code cannot be found </exception>
/// <exception cref="FormatException"> if a QR code cannot be decoded </exception>
/// <exception cref="ChecksumException"> if error correction fails </exception>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: public com.google.zxing.Result decode(com.google.zxing.BinaryBitmap image) throws com.google.zxing.NotFoundException, com.google.zxing.ChecksumException, com.google.zxing.FormatException
public Result decode(BinaryBitmap image)
{
return decode(image, null);
}
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: public com.google.zxing.Result decode(com.google.zxing.BinaryBitmap image, java.util.Map<com.google.zxing.DecodeHintType,?> hints) throws com.google.zxing.NotFoundException, com.google.zxing.ChecksumException, com.google.zxing.FormatException
public Result decode(BinaryBitmap image, IDictionary<DecodeHintType, object> hints)
{
DecoderResult decoderResult;
ResultPoint[] points;
if (hints != null && hints.ContainsKey(DecodeHintType.PURE_BARCODE))
{
BitMatrix bits = extractPureBits(image.BlackMatrix);
decoderResult = decoder.decode(bits, hints);
points = NO_POINTS;
}
else
{
DetectorResult detectorResult = (new Detector(image.BlackMatrix)).detect(hints);
decoderResult = decoder.decode(detectorResult.Bits, hints);
points = detectorResult.Points;
}
Result result = new Result(decoderResult.Text, decoderResult.RawBytes, points, BarcodeFormat.QR_CODE);
IList<sbyte[]> byteSegments = decoderResult.ByteSegments;
if (byteSegments != null)
{
result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
}
string ecLevel = decoderResult.ECLevel;
if (ecLevel != null)
{
result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
}
return result;
}
public void reset()
{
// do nothing
}
/// <summary>
/// This method detects a code in a "pure" image -- that is, pure monochrome image
/// which contains only an unrotated, unskewed, image of a code, with some white border
/// around it. This is a specialized method that works exceptionally fast in this special
/// case.
/// </summary>
/// <seealso cref= com.google.zxing.pdf417.PDF417Reader#extractPureBits(BitMatrix) </seealso>
/// <seealso cref= com.google.zxing.datamatrix.DataMatrixReader#extractPureBits(BitMatrix) </seealso>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: private static com.google.zxing.common.BitMatrix extractPureBits(com.google.zxing.common.BitMatrix image) throws com.google.zxing.NotFoundException
private static BitMatrix extractPureBits(BitMatrix image)
{
int[] leftTopBlack = image.TopLeftOnBit;
int[] rightBottomBlack = image.BottomRightOnBit;
if (leftTopBlack == null || rightBottomBlack == null)
{
throw NotFoundException.NotFoundInstance;
}
float moduleSize = getModuleSize(leftTopBlack, image);
int top = leftTopBlack[1];
int bottom = rightBottomBlack[1];
int left = leftTopBlack[0];
int right = rightBottomBlack[0];
if (bottom - top != right - left)
{
// Special case, where bottom-right module wasn't black so we found something else in the last row
// Assume it's a square, so use height as the width
right = left + (bottom - top);
}
int matrixWidth = (int)Math.Round((right - left + 1) / moduleSize);
int matrixHeight = (int) Math.Round((bottom - top + 1) / moduleSize);
if (matrixWidth <= 0 || matrixHeight <= 0)
{
throw NotFoundException.NotFoundInstance;
}
if (matrixHeight != matrixWidth)
{
// Only possibly decode square regions
throw NotFoundException.NotFoundInstance;
}
// 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.
int nudge = (int)(moduleSize / 2.0f);
top += nudge;
left += nudge;
// Now just read off the bits
BitMatrix bits = new BitMatrix(matrixWidth, matrixHeight);
for (int y = 0; y < matrixHeight; y++)
{
int iOffset = top + (int)(y * moduleSize);
for (int x = 0; x < matrixWidth; x++)
{
if (image.get(left + (int)(x * moduleSize), iOffset))
{
bits.set(x, y);
}
}
}
return bits;
}
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: private static float moduleSize(int[] leftTopBlack, com.google.zxing.common.BitMatrix image) throws com.google.zxing.NotFoundException
private static float getModuleSize(int[] leftTopBlack, BitMatrix image)
{
int height = image.Height;
int width = image.Width;
int x = leftTopBlack[0];
int y = leftTopBlack[1];
bool inBlack = true;
int transitions = 0;
while (x < width && y < height)
{
if (inBlack != image.get(x, y))
{
if (++transitions == 5)
{
break;
}
inBlack = !inBlack;
}
x++;
y++;
}
if (x == width || y == height)
{
throw NotFoundException.NotFoundInstance;
}
return (x - leftTopBlack[0]) / 7.0f;
}
}
}