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https://github.com/zxing/zxing.git
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7616c4d06d
git-svn-id: https://zxing.googlecode.com/svn/trunk@2558 59b500cc-1b3d-0410-9834-0bbf25fbcc57
368 lines
15 KiB
C#
Executable file
368 lines
15 KiB
C#
Executable file
using System;
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using System.Collections;
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using System.Collections.Generic;
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/*
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* Copyright 2008 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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namespace com.google.zxing.oned
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{
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using BinaryBitmap = com.google.zxing.BinaryBitmap;
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using ChecksumException = com.google.zxing.ChecksumException;
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using DecodeHintType = com.google.zxing.DecodeHintType;
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using FormatException = com.google.zxing.FormatException;
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using NotFoundException = com.google.zxing.NotFoundException;
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using Reader = com.google.zxing.Reader;
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using ReaderException = com.google.zxing.ReaderException;
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using Result = com.google.zxing.Result;
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using ResultMetadataType = com.google.zxing.ResultMetadataType;
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using ResultPoint = com.google.zxing.ResultPoint;
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using BitArray = com.google.zxing.common.BitArray;
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/// <summary>
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/// Encapsulates functionality and implementation that is common to all families
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/// of one-dimensional barcodes.
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///
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/// @author dswitkin@google.com (Daniel Switkin)
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/// @author Sean Owen
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/// </summary>
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public abstract class OneDReader : com.google.zxing.Reader
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{
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protected internal const int INTEGER_MATH_SHIFT = 8;
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protected internal static readonly int PATTERN_MATCH_RESULT_SCALE_FACTOR = 1 << INTEGER_MATH_SHIFT;
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
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//ORIGINAL LINE: public com.google.zxing.Result decode(com.google.zxing.BinaryBitmap image) throws com.google.zxing.NotFoundException, com.google.zxing.FormatException
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public virtual Result decode(BinaryBitmap image)
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{
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return decode(image, null);
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}
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// Note that we don't try rotation without the try harder flag, even if rotation was supported.
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
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//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.FormatException
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public virtual Result decode(BinaryBitmap image, IDictionary<DecodeHintType, object> hints)
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{
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try
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{
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return doDecode(image, hints);
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}
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catch (NotFoundException nfe)
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{
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bool tryHarder = hints != null && hints.ContainsKey(DecodeHintType.TRY_HARDER);
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if (tryHarder && image.RotateSupported)
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{
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BinaryBitmap rotatedImage = image.rotateCounterClockwise();
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Result result = doDecode(rotatedImage, hints);
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// Record that we found it rotated 90 degrees CCW / 270 degrees CW
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//JAVA TO C# CONVERTER TODO TASK: Java wildcard generics are not converted to .NET:
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//ORIGINAL LINE: java.util.Map<com.google.zxing.ResultMetadataType,?> metadata = result.getResultMetadata();
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IDictionary<ResultMetadataType, object> metadata = result.ResultMetadata;
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int orientation = 270;
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if (metadata != null && metadata.ContainsKey(ResultMetadataType.ORIENTATION))
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{
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// But if we found it reversed in doDecode(), add in that result here:
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orientation = (orientation + (int) metadata[ResultMetadataType.ORIENTATION]) % 360;
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}
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result.putMetadata(ResultMetadataType.ORIENTATION, orientation);
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// Update result points
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ResultPoint[] points = result.ResultPoints;
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if (points != null)
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{
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int height = rotatedImage.Height;
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for (int i = 0; i < points.Length; i++)
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{
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points[i] = new ResultPoint(height - points[i].Y - 1, points[i].X);
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}
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}
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return result;
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}
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else
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{
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throw nfe;
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}
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}
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}
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public virtual void reset()
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{
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// do nothing
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}
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/// <summary>
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/// We're going to examine rows from the middle outward, searching alternately above and below the
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/// middle, and farther out each time. rowStep is the number of rows between each successive
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/// attempt above and below the middle. So we'd scan row middle, then middle - rowStep, then
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/// middle + rowStep, then middle - (2 * rowStep), etc.
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/// rowStep is bigger as the image is taller, but is always at least 1. We've somewhat arbitrarily
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/// decided that moving up and down by about 1/16 of the image is pretty good; we try more of the
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/// image if "trying harder".
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/// </summary>
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/// <param name="image"> The image to decode </param>
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/// <param name="hints"> Any hints that were requested </param>
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/// <returns> The contents of the decoded barcode </returns>
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/// <exception cref="NotFoundException"> Any spontaneous errors which occur </exception>
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
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//ORIGINAL LINE: private com.google.zxing.Result doDecode(com.google.zxing.BinaryBitmap image, java.util.Map<com.google.zxing.DecodeHintType,?> hints) throws com.google.zxing.NotFoundException
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private Result doDecode(BinaryBitmap image, IDictionary<DecodeHintType, object> hints)
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{
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int width = image.Width;
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int height = image.Height;
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BitArray row = new BitArray(width);
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int middle = height >> 1;
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bool tryHarder = hints != null && hints.ContainsKey(DecodeHintType.TRY_HARDER);
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int rowStep = Math.Max(1, height >> (tryHarder ? 8 : 5));
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int maxLines;
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if (tryHarder)
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{
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maxLines = height; // Look at the whole image, not just the center
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}
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else
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{
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maxLines = 15; // 15 rows spaced 1/32 apart is roughly the middle half of the image
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}
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for (int x = 0; x < maxLines; x++)
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{
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// Scanning from the middle out. Determine which row we're looking at next:
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int rowStepsAboveOrBelow = (x + 1) >> 1;
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bool isAbove = (x & 0x01) == 0; // i.e. is x even?
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int rowNumber = middle + rowStep * (isAbove ? rowStepsAboveOrBelow : -rowStepsAboveOrBelow);
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if (rowNumber < 0 || rowNumber >= height)
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{
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// Oops, if we run off the top or bottom, stop
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break;
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}
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// Estimate black point for this row and load it:
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try
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{
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row = image.getBlackRow(rowNumber, row);
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}
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catch (NotFoundException nfe)
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{
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continue;
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}
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// While we have the image data in a BitArray, it's fairly cheap to reverse it in place to
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// handle decoding upside down barcodes.
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for (int attempt = 0; attempt < 2; attempt++)
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{
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if (attempt == 1) // trying again?
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{
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row.reverse(); // reverse the row and continue
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// This means we will only ever draw result points *once* in the life of this method
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// since we want to avoid drawing the wrong points after flipping the row, and,
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// don't want to clutter with noise from every single row scan -- just the scans
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// that start on the center line.
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if (hints != null && hints.ContainsKey(DecodeHintType.NEED_RESULT_POINT_CALLBACK))
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{
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//IDictionary<DecodeHintType, object> newHints = new EnumMap<DecodeHintType, object>(typeof(DecodeHintType));
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Dictionary<DecodeHintType,object> newHints = new Dictionary<DecodeHintType,object>();
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//JAVA TO C# CONVERTER TODO TASK: There is no .NET Dictionary equivalent to the Java 'putAll' method:
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//newHints.putAll(hints);
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//foreach (DecodeHintType dht in Enum.GetValues(typeof(DecodeHintType)))
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//{
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// newHints.Add(dht,dht);
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//}
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foreach (KeyValuePair<DecodeHintType,object> kvp in hints)
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{
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newHints.Add(kvp.Key,kvp.Value);
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}
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if (newHints.ContainsKey(DecodeHintType.NEED_RESULT_POINT_CALLBACK))
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{
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newHints.Remove(DecodeHintType.NEED_RESULT_POINT_CALLBACK);
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}
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hints = newHints;
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}
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}
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try
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{
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// Look for a barcode
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Result result = decodeRow(rowNumber, row, hints);
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// We found our barcode
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if (attempt == 1)
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{
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// But it was upside down, so note that
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result.putMetadata(ResultMetadataType.ORIENTATION, 180);
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// And remember to flip the result points horizontally.
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ResultPoint[] points = result.ResultPoints;
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if (points != null)
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{
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points[0] = new ResultPoint(width - points[0].X - 1, points[0].Y);
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points[1] = new ResultPoint(width - points[1].X - 1, points[1].Y);
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}
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}
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return result;
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}
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catch (ReaderException re)
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{
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// continue -- just couldn't decode this row
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}
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}
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}
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throw NotFoundException.NotFoundInstance;
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}
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/// <summary>
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/// Records the size of successive runs of white and black pixels in a row, starting at a given point.
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/// The values are recorded in the given array, and the number of runs recorded is equal to the size
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/// of the array. If the row starts on a white pixel at the given start point, then the first count
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/// recorded is the run of white pixels starting from that point; likewise it is the count of a run
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/// of black pixels if the row begin on a black pixels at that point.
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/// </summary>
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/// <param name="row"> row to count from </param>
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/// <param name="start"> offset into row to start at </param>
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/// <param name="counters"> array into which to record counts </param>
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/// <exception cref="NotFoundException"> if counters cannot be filled entirely from row before running out
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/// of pixels </exception>
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
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//ORIGINAL LINE: protected static void recordPattern(com.google.zxing.common.BitArray row, int start, int[] counters) throws com.google.zxing.NotFoundException
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protected internal static void recordPattern(BitArray row, int start, int[] counters)
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{
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int numCounters = counters.Length;
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//Arrays.fill(counters, 0, numCounters, 0);
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counters.Fill(0);
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int end = row.Size;
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if (start >= end)
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{
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throw NotFoundException.NotFoundInstance;
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}
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bool isWhite = !row.get(start);
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int counterPosition = 0;
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int i = start;
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while (i < end)
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{
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if (row.get(i) ^ isWhite) // that is, exactly one is true
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{
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counters[counterPosition]++;
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}
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else
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{
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counterPosition++;
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if (counterPosition == numCounters)
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{
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break;
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}
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else
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{
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counters[counterPosition] = 1;
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isWhite = !isWhite;
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}
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}
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i++;
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}
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// If we read fully the last section of pixels and filled up our counters -- or filled
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// the last counter but ran off the side of the image, OK. Otherwise, a problem.
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if (!(counterPosition == numCounters || (counterPosition == numCounters - 1 && i == end)))
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{
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throw NotFoundException.NotFoundInstance;
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}
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}
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
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//ORIGINAL LINE: protected static void recordPatternInReverse(com.google.zxing.common.BitArray row, int start, int[] counters) throws com.google.zxing.NotFoundException
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protected internal static void recordPatternInReverse(BitArray row, int start, int[] counters)
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{
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// This could be more efficient I guess
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int numTransitionsLeft = counters.Length;
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bool last = row.get(start);
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while (start > 0 && numTransitionsLeft >= 0)
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{
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if (row.get(--start) != last)
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{
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numTransitionsLeft--;
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last = !last;
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}
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}
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if (numTransitionsLeft >= 0)
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{
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throw NotFoundException.NotFoundInstance;
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}
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recordPattern(row, start + 1, counters);
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}
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/// <summary>
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/// Determines how closely a set of observed counts of runs of black/white values matches a given
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/// target pattern. This is reported as the ratio of the total variance from the expected pattern
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/// proportions across all pattern elements, to the length of the pattern.
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/// </summary>
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/// <param name="counters"> observed counters </param>
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/// <param name="pattern"> expected pattern </param>
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/// <param name="maxIndividualVariance"> The most any counter can differ before we give up </param>
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/// <returns> ratio of total variance between counters and pattern compared to total pattern size,
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/// where the ratio has been multiplied by 256. So, 0 means no variance (perfect match); 256 means
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/// the total variance between counters and patterns equals the pattern length, higher values mean
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/// even more variance </returns>
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protected internal static int patternMatchVariance(int[] counters, int[] pattern, int maxIndividualVariance)
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{
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int numCounters = counters.Length;
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int total = 0;
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int patternLength = 0;
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for (int i = 0; i < numCounters; i++)
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{
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total += counters[i];
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patternLength += pattern[i];
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}
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if (total < patternLength)
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{
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// If we don't even have one pixel per unit of bar width, assume this is too small
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// to reliably match, so fail:
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return int.MaxValue;
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}
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// We're going to fake floating-point math in integers. We just need to use more bits.
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// Scale up patternLength so that intermediate values below like scaledCounter will have
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// more "significant digits"
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int unitBarWidth = (total << INTEGER_MATH_SHIFT) / patternLength;
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maxIndividualVariance = (maxIndividualVariance * unitBarWidth) >> INTEGER_MATH_SHIFT;
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int totalVariance = 0;
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for (int x = 0; x < numCounters; x++)
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{
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int counter = counters[x] << INTEGER_MATH_SHIFT;
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int scaledPattern = pattern[x] * unitBarWidth;
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int variance = counter > scaledPattern ? counter - scaledPattern : scaledPattern - counter;
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if (variance > maxIndividualVariance)
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{
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return int.MaxValue;
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}
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totalVariance += variance;
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}
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return totalVariance / total;
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}
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/// <summary>
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/// <p>Attempts to decode a one-dimensional barcode format given a single row of
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/// an image.</p>
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/// </summary>
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/// <param name="rowNumber"> row number from top of the row </param>
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/// <param name="row"> the black/white pixel data of the row </param>
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/// <param name="hints"> decode hints </param>
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/// <returns> <seealso cref="Result"/> containing encoded string and start/end of barcode </returns>
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/// <exception cref="NotFoundException"> if an error occurs or barcode cannot be found </exception>
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
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//ORIGINAL LINE: public abstract com.google.zxing.Result decodeRow(int rowNumber, com.google.zxing.common.BitArray row, java.util.Map<com.google.zxing.DecodeHintType,?> hints) throws com.google.zxing.NotFoundException, com.google.zxing.ChecksumException, com.google.zxing.FormatException;
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public abstract Result decodeRow(int rowNumber, BitArray row, IDictionary<DecodeHintType, object> hints);
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}
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} |