/// <summary> Identify where the end of the middle / payload section ends. /// /// </summary> /// <param name="row">row of black/white values to search /// </param> /// <returns> Array, containing index of start of 'end block' and end of 'end /// block' /// </returns> /// <throws> ReaderException </throws> internal int[] decodeEnd(BitArray row) { // For convenience, reverse the row and then // search from 'the start' for the end block row.reverse(); try { int endStart = skipWhiteSpace(row); int[] endPattern = findGuardPattern(row, endStart, END_PATTERN_REVERSED); // The start & end patterns must be pre/post fixed by a quiet zone. This // zone must be at least 10 times the width of a narrow line. // ref: http://www.barcode-1.net/i25code.html validateQuietZone(row, endPattern[0]); // Now recalculate the indices of where the 'endblock' starts & stops to // accommodate // the reversed nature of the search int temp = endPattern[0]; endPattern[0] = row.Size - endPattern[1]; endPattern[1] = row.Size - temp; return(endPattern); } finally { // Put the row back the right way. row.reverse(); } }
/// <summary> Identify where the end of the middle / payload section ends. /// /// </summary> /// <param name="row">row of black/white values to search /// </param> /// <returns> Array, containing index of start of 'end block' and end of 'end /// block' /// </returns> /// <throws> ReaderException </throws> internal int[] decodeEnd(BitArray row) { // For convenience, reverse the row and then // search from 'the start' for the end block row.reverse(); try { int endStart = skipWhiteSpace(row); int[] endPattern = findGuardPattern(row, endStart, END_PATTERN_REVERSED); // The start & end patterns must be pre/post fixed by a quiet zone. This // zone must be at least 10 times the width of a narrow line. // ref: http://www.barcode-1.net/i25code.html validateQuietZone(row, endPattern[0]); // Now recalculate the indices of where the 'endblock' starts & stops to // accommodate // the reversed nature of the search int temp = endPattern[0]; endPattern[0] = row.Size - endPattern[1]; endPattern[1] = row.Size - temp; return endPattern; } finally { // Put the row back the right way. row.reverse(); } }
/// <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> 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; }