mirror of
https://github.com/zxing/zxing.git
synced 2024-09-20 13:37:34 -07:00
b6128650bb
git-svn-id: https://zxing.googlecode.com/svn/trunk@1951 59b500cc-1b3d-0410-9834-0bbf25fbcc57
333 lines
13 KiB
C#
Executable file
333 lines
13 KiB
C#
Executable file
/*
|
|
* Copyright 2008 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 BinaryBitmap = com.google.zxing.BinaryBitmap;
|
|
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 ResultMetadataType = com.google.zxing.ResultMetadataType;
|
|
using ResultPoint = com.google.zxing.ResultPoint;
|
|
using BitArray = com.google.zxing.common.BitArray;
|
|
namespace com.google.zxing.oned
|
|
{
|
|
|
|
/// <summary> Encapsulates functionality and implementation that is common to all families
|
|
/// of one-dimensional barcodes.
|
|
///
|
|
/// </summary>
|
|
/// <author> dswitkin@google.com (Daniel Switkin)
|
|
/// </author>
|
|
/// <author> Sean Owen
|
|
/// </author>
|
|
/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
|
|
/// </author>
|
|
public abstract class OneDReader : Reader
|
|
{
|
|
|
|
private const int INTEGER_MATH_SHIFT = 8;
|
|
//UPGRADE_NOTE: Final was removed from the declaration of 'PATTERN_MATCH_RESULT_SCALE_FACTOR '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
|
|
internal static readonly int PATTERN_MATCH_RESULT_SCALE_FACTOR = 1 << INTEGER_MATH_SHIFT;
|
|
|
|
public virtual Result decode(BinaryBitmap image)
|
|
{
|
|
return decode(image, null);
|
|
}
|
|
|
|
// Note that we don't try rotation without the try harder flag, even if rotation was supported.
|
|
public virtual Result decode(BinaryBitmap image, System.Collections.Hashtable hints)
|
|
{
|
|
try
|
|
{
|
|
return doDecode(image, hints);
|
|
}
|
|
catch (ReaderException re)
|
|
{
|
|
bool tryHarder = hints != null && hints.ContainsKey(DecodeHintType.TRY_HARDER);
|
|
if (tryHarder && image.RotateSupported)
|
|
{
|
|
BinaryBitmap rotatedImage = image.rotateCounterClockwise();
|
|
Result result = doDecode(rotatedImage, hints);
|
|
// Record that we found it rotated 90 degrees CCW / 270 degrees CW
|
|
System.Collections.Hashtable metadata = result.ResultMetadata;
|
|
int orientation = 270;
|
|
if (metadata != null && metadata.ContainsKey(ResultMetadataType.ORIENTATION))
|
|
{
|
|
// But if we found it reversed in doDecode(), add in that result here:
|
|
orientation = (orientation + ((System.Int32) metadata[ResultMetadataType.ORIENTATION])) % 360;
|
|
}
|
|
result.putMetadata(ResultMetadataType.ORIENTATION, (System.Object) orientation);
|
|
// Update result points
|
|
ResultPoint[] points = result.ResultPoints;
|
|
int height = rotatedImage.Height;
|
|
for (int i = 0; i < points.Length; i++)
|
|
{
|
|
points[i] = new ResultPoint(height - points[i].Y - 1, points[i].X);
|
|
}
|
|
return result;
|
|
}
|
|
else
|
|
{
|
|
throw re;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// <summary> We're going to examine rows from the middle outward, searching alternately above and below the
|
|
/// middle, and farther out each time. rowStep is the number of rows between each successive
|
|
/// attempt above and below the middle. So we'd scan row middle, then middle - rowStep, then
|
|
/// middle + rowStep, then middle - (2 * rowStep), etc.
|
|
/// rowStep is bigger as the image is taller, but is always at least 1. We've somewhat arbitrarily
|
|
/// decided that moving up and down by about 1/16 of the image is pretty good; we try more of the
|
|
/// image if "trying harder".
|
|
///
|
|
/// </summary>
|
|
/// <param name="image">The image to decode
|
|
/// </param>
|
|
/// <param name="hints">Any hints that were requested
|
|
/// </param>
|
|
/// <returns> The contents of the decoded barcode
|
|
/// </returns>
|
|
/// <throws> ReaderException Any spontaneous errors which occur </throws>
|
|
private Result doDecode(BinaryBitmap image, System.Collections.Hashtable hints)
|
|
{
|
|
int width = image.Width;
|
|
int height = image.Height;
|
|
BitArray row = new BitArray(width);
|
|
|
|
int middle = height >> 1;
|
|
bool tryHarder = hints != null && hints.ContainsKey(DecodeHintType.TRY_HARDER);
|
|
int rowStep = System.Math.Max(1, height >> (tryHarder?7:4));
|
|
int maxLines;
|
|
if (tryHarder)
|
|
{
|
|
maxLines = height; // Look at the whole image, not just the center
|
|
}
|
|
else
|
|
{
|
|
maxLines = 9; // Nine rows spaced 1/16 apart is roughly the middle half of the image
|
|
}
|
|
|
|
for (int x = 0; x < maxLines; x++)
|
|
{
|
|
|
|
// Scanning from the middle out. Determine which row we're looking at next:
|
|
int rowStepsAboveOrBelow = (x + 1) >> 1;
|
|
bool isAbove = (x & 0x01) == 0; // i.e. is x even?
|
|
int rowNumber = middle + rowStep * (isAbove?rowStepsAboveOrBelow:- rowStepsAboveOrBelow);
|
|
if (rowNumber < 0 || rowNumber >= height)
|
|
{
|
|
// Oops, if we run off the top or bottom, stop
|
|
break;
|
|
}
|
|
|
|
// Estimate black point for this row and load it:
|
|
try
|
|
{
|
|
row = image.getBlackRow(rowNumber, row);
|
|
}
|
|
catch (ReaderException)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
// While we have the image data in a BitArray, it's fairly cheap to reverse it in place to
|
|
// handle decoding upside down barcodes.
|
|
for (int attempt = 0; attempt < 2; attempt++)
|
|
{
|
|
if (attempt == 1)
|
|
{
|
|
// trying again?
|
|
row.reverse(); // reverse the row and continue
|
|
// This means we will only ever draw result points *once* in the life of this method
|
|
// since we want to avoid drawing the wrong points after flipping the row, and,
|
|
// don't want to clutter with noise from every single row scan -- just the scans
|
|
// that start on the center line.
|
|
if (hints != null && hints.ContainsKey(DecodeHintType.NEED_RESULT_POINT_CALLBACK))
|
|
{
|
|
System.Collections.Hashtable newHints = System.Collections.Hashtable.Synchronized(new System.Collections.Hashtable()); // Can't use clone() in J2ME
|
|
System.Collections.IEnumerator hintEnum = hints.Keys.GetEnumerator();
|
|
//UPGRADE_TODO: Method 'java.util.Enumeration.hasMoreElements' was converted to 'System.Collections.IEnumerator.MoveNext' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilEnumerationhasMoreElements'"
|
|
while (hintEnum.MoveNext())
|
|
{
|
|
//UPGRADE_TODO: Method 'java.util.Enumeration.nextElement' was converted to 'System.Collections.IEnumerator.Current' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javautilEnumerationnextElement'"
|
|
System.Object key = hintEnum.Current;
|
|
if (!key.Equals(DecodeHintType.NEED_RESULT_POINT_CALLBACK))
|
|
{
|
|
newHints[key] = hints[key];
|
|
}
|
|
}
|
|
hints = newHints;
|
|
}
|
|
}
|
|
try
|
|
{
|
|
// Look for a barcode
|
|
Result result = decodeRow(rowNumber, row, hints);
|
|
// We found our barcode
|
|
if (attempt == 1)
|
|
{
|
|
// But it was upside down, so note that
|
|
result.putMetadata(ResultMetadataType.ORIENTATION, (System.Object) 180);
|
|
// And remember to flip the result points horizontally.
|
|
ResultPoint[] points = result.ResultPoints;
|
|
points[0] = new ResultPoint(width - points[0].X - 1, points[0].Y);
|
|
points[1] = new ResultPoint(width - points[1].X - 1, points[1].Y);
|
|
}
|
|
return result;
|
|
}
|
|
catch (ReaderException)
|
|
{
|
|
// continue -- just couldn't decode this row
|
|
}
|
|
}
|
|
}
|
|
|
|
throw ReaderException.Instance;
|
|
}
|
|
|
|
/// <summary> Records the size of successive runs of white and black pixels in a row, starting at a given point.
|
|
/// The values are recorded in the given array, and the number of runs recorded is equal to the size
|
|
/// of the array. If the row starts on a white pixel at the given start point, then the first count
|
|
/// recorded is the run of white pixels starting from that point; likewise it is the count of a run
|
|
/// of black pixels if the row begin on a black pixels at that point.
|
|
///
|
|
/// </summary>
|
|
/// <param name="row">row to count from
|
|
/// </param>
|
|
/// <param name="start">offset into row to start at
|
|
/// </param>
|
|
/// <param name="counters">array into which to record counts
|
|
/// </param>
|
|
/// <throws> ReaderException if counters cannot be filled entirely from row before running out </throws>
|
|
/// <summary> of pixels
|
|
/// </summary>
|
|
internal static void recordPattern(BitArray row, int start, int[] counters)
|
|
{
|
|
int numCounters = counters.Length;
|
|
for (int i = 0; i < numCounters; i++)
|
|
{
|
|
counters[i] = 0;
|
|
}
|
|
int end = row.Size;
|
|
if (start >= end)
|
|
{
|
|
throw ReaderException.Instance;
|
|
}
|
|
bool isWhite = !row.get_Renamed(start);
|
|
int counterPosition = 0;
|
|
int i2 = start;
|
|
while (i2 < end)
|
|
{
|
|
bool pixel = row.get_Renamed(i2);
|
|
if (pixel ^ isWhite)
|
|
{
|
|
// that is, exactly one is true
|
|
counters[counterPosition]++;
|
|
}
|
|
else
|
|
{
|
|
counterPosition++;
|
|
if (counterPosition == numCounters)
|
|
{
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
counters[counterPosition] = 1;
|
|
isWhite ^= true; // isWhite = !isWhite;
|
|
}
|
|
}
|
|
i2++;
|
|
}
|
|
// If we read fully the last section of pixels and filled up our counters -- or filled
|
|
// the last counter but ran off the side of the image, OK. Otherwise, a problem.
|
|
if (!(counterPosition == numCounters || (counterPosition == numCounters - 1 && i2 == end)))
|
|
{
|
|
throw ReaderException.Instance;
|
|
}
|
|
}
|
|
|
|
/// <summary> Determines how closely a set of observed counts of runs of black/white values matches a given
|
|
/// target pattern. This is reported as the ratio of the total variance from the expected pattern
|
|
/// proportions across all pattern elements, to the length of the pattern.
|
|
///
|
|
/// </summary>
|
|
/// <param name="counters">observed counters
|
|
/// </param>
|
|
/// <param name="pattern">expected pattern
|
|
/// </param>
|
|
/// <param name="maxIndividualVariance">The most any counter can differ before we give up
|
|
/// </param>
|
|
/// <returns> ratio of total variance between counters and pattern compared to total pattern size,
|
|
/// where the ratio has been multiplied by 256. So, 0 means no variance (perfect match); 256 means
|
|
/// the total variance between counters and patterns equals the pattern length, higher values mean
|
|
/// even more variance
|
|
/// </returns>
|
|
internal static int patternMatchVariance(int[] counters, int[] pattern, int maxIndividualVariance)
|
|
{
|
|
int numCounters = counters.Length;
|
|
int total = 0;
|
|
int patternLength = 0;
|
|
for (int i = 0; i < numCounters; i++)
|
|
{
|
|
total += counters[i];
|
|
patternLength += pattern[i];
|
|
}
|
|
if (total < patternLength)
|
|
{
|
|
// If we don't even have one pixel per unit of bar width, assume this is too small
|
|
// to reliably match, so fail:
|
|
return System.Int32.MaxValue;
|
|
}
|
|
// We're going to fake floating-point math in integers. We just need to use more bits.
|
|
// Scale up patternLength so that intermediate values below like scaledCounter will have
|
|
// more "significant digits"
|
|
int unitBarWidth = (total << INTEGER_MATH_SHIFT) / patternLength;
|
|
maxIndividualVariance = (maxIndividualVariance * unitBarWidth) >> INTEGER_MATH_SHIFT;
|
|
|
|
int totalVariance = 0;
|
|
for (int x = 0; x < numCounters; x++)
|
|
{
|
|
int counter = counters[x] << INTEGER_MATH_SHIFT;
|
|
int scaledPattern = pattern[x] * unitBarWidth;
|
|
int variance = counter > scaledPattern?counter - scaledPattern:scaledPattern - counter;
|
|
if (variance > maxIndividualVariance)
|
|
{
|
|
return System.Int32.MaxValue;
|
|
}
|
|
totalVariance += variance;
|
|
}
|
|
return totalVariance / total;
|
|
}
|
|
|
|
/// <summary> <p>Attempts to decode a one-dimensional barcode format given a single row of
|
|
/// an image.</p>
|
|
///
|
|
/// </summary>
|
|
/// <param name="rowNumber">row number from top of the row
|
|
/// </param>
|
|
/// <param name="row">the black/white pixel data of the row
|
|
/// </param>
|
|
/// <param name="hints">decode hints
|
|
/// </param>
|
|
/// <returns> {@link Result} containing encoded string and start/end of barcode
|
|
/// </returns>
|
|
/// <throws> ReaderException if an error occurs or barcode cannot be found </throws>
|
|
public abstract Result decodeRow(int rowNumber, BitArray row, System.Collections.Hashtable hints);
|
|
}
|
|
}
|