/// <summary>
/// Gets the row indicator column.
/// </summary>
/// <returns>The row indicator column.</returns>
/// <param name="image">Image.</param>
/// <param name="boundingBox">Bounding box.</param>
/// <param name="startPoint">Start point.</param>
/// <param name="leftToRight">If set to <c>true</c> left to right.</param>
/// <param name="minCodewordWidth">Minimum codeword width.</param>
/// <param name="maxCodewordWidth">Max codeword width.</param>
private static DetectionResultRowIndicatorColumn getRowIndicatorColumn(BitMatrix image,
BoundingBox boundingBox,
ResultPoint startPoint,
bool leftToRight,
int minCodewordWidth,
int maxCodewordWidth)
{
DetectionResultRowIndicatorColumn rowIndicatorColumn = new DetectionResultRowIndicatorColumn(boundingBox, leftToRight);
for (int i = 0; i < 2; i++)
{
int increment = i == 0 ? 1 : -1;
int startColumn = (int)startPoint.X;
for (int imageRow = (int)startPoint.Y; imageRow <= boundingBox.MaxY &&
imageRow >= boundingBox.MinY; imageRow += increment)
{
Codeword codeword = detectCodeword(image, 0, image.Width, leftToRight, startColumn, imageRow,
minCodewordWidth, maxCodewordWidth);
if (codeword != null)
{
rowIndicatorColumn.setCodeword(imageRow, codeword);
if (leftToRight)
{
startColumn = codeword.StartX;
}
else
{
startColumn = codeword.EndX;
}
}
}
}
return(rowIndicatorColumn);
}
/// <summary>
/// Gets the barcode metadata.
/// </summary>
/// <returns>The barcode metadata.</returns>
/// <param name="leftRowIndicatorColumn">Left row indicator column.</param>
/// <param name="rightRowIndicatorColumn">Right row indicator column.</param>
private static BarcodeMetadata getBarcodeMetadata(DetectionResultRowIndicatorColumn leftRowIndicatorColumn,
DetectionResultRowIndicatorColumn rightRowIndicatorColumn)
{
BarcodeMetadata leftBarcodeMetadata;
if (leftRowIndicatorColumn == null ||
(leftBarcodeMetadata = leftRowIndicatorColumn.getBarcodeMetadata()) == null)
{
return(rightRowIndicatorColumn == null ? null : rightRowIndicatorColumn.getBarcodeMetadata());
}
BarcodeMetadata rightBarcodeMetadata;
if (rightRowIndicatorColumn == null ||
(rightBarcodeMetadata = rightRowIndicatorColumn.getBarcodeMetadata()) == null)
{
return(leftBarcodeMetadata);
}
if (leftBarcodeMetadata.ColumnCount != rightBarcodeMetadata.ColumnCount &&
leftBarcodeMetadata.ErrorCorrectionLevel != rightBarcodeMetadata.ErrorCorrectionLevel &&
leftBarcodeMetadata.RowCount != rightBarcodeMetadata.RowCount)
{
return(null);
}
return(leftBarcodeMetadata);
}
/// <summary>
/// Merge the specified leftRowIndicatorColumn and rightRowIndicatorColumn.
/// </summary>
/// <param name="leftRowIndicatorColumn">Left row indicator column.</param>
/// <param name="rightRowIndicatorColumn">Right row indicator column.</param>
private static DetectionResult merge(DetectionResultRowIndicatorColumn leftRowIndicatorColumn,
DetectionResultRowIndicatorColumn rightRowIndicatorColumn)
{
if (leftRowIndicatorColumn == null && rightRowIndicatorColumn == null)
{
return(null);
}
BarcodeMetadata barcodeMetadata = getBarcodeMetadata(leftRowIndicatorColumn, rightRowIndicatorColumn);
if (barcodeMetadata == null)
{
return(null);
}
BoundingBox boundingBox = BoundingBox.merge(adjustBoundingBox(leftRowIndicatorColumn),
adjustBoundingBox(rightRowIndicatorColumn));
return(new DetectionResult(barcodeMetadata, boundingBox));
}
/// <summary>
/// Adjusts the bounding box.
/// </summary>
/// <returns>The bounding box.</returns>
/// <param name="rowIndicatorColumn">Row indicator column.</param>
private static BoundingBox adjustBoundingBox(DetectionResultRowIndicatorColumn rowIndicatorColumn)
{
if (rowIndicatorColumn == null)
{
return(null);
}
int[] rowHeights = rowIndicatorColumn.getRowHeights();
if (rowHeights == null)
{
return(null);
}
int maxRowHeight = getMax(rowHeights);
int missingStartRows = 0;
foreach (int rowHeight in rowHeights)
{
missingStartRows += maxRowHeight - rowHeight;
if (rowHeight > 0)
{
break;
}
}
Codeword[] codewords = rowIndicatorColumn.Codewords;
for (int row = 0; missingStartRows > 0 && codewords[row] == null; row++)
{
missingStartRows--;
}
int missingEndRows = 0;
for (int row = rowHeights.Length - 1; row >= 0; row--)
{
missingEndRows += maxRowHeight - rowHeights[row];
if (rowHeights[row] > 0)
{
break;
}
}
for (int row = codewords.Length - 1; missingEndRows > 0 && codewords[row] == null; row--)
{
missingEndRows--;
}
return(rowIndicatorColumn.Box.addMissingRows(missingStartRows, missingEndRows, rowIndicatorColumn.IsLeft));
}
/// <summary>
/// Decode the specified image, imageTopLeft, imageBottomLeft, imageTopRight, imageBottomRight, minCodewordWidth
/// and maxCodewordWidth.
/// TODO: don't pass in minCodewordWidth and maxCodewordWidth, pass in barcode columns for start and stop pattern
/// columns. That way width can be deducted from the pattern column.
/// This approach also allows to detect more details about the barcode, e.g. if a bar type (white or black) is wider
/// than it should be. This can happen if the scanner used a bad blackpoint.
/// </summary>
/// <param name="image">Image.</param>
/// <param name="imageTopLeft">Image top left.</param>
/// <param name="imageBottomLeft">Image bottom left.</param>
/// <param name="imageTopRight">Image top right.</param>
/// <param name="imageBottomRight">Image bottom right.</param>
/// <param name="minCodewordWidth">Minimum codeword width.</param>
/// <param name="maxCodewordWidth">Max codeword width.</param>
public static DecoderResult decode(BitMatrix image,
ResultPoint imageTopLeft,
ResultPoint imageBottomLeft,
ResultPoint imageTopRight,
ResultPoint imageBottomRight,
int minCodewordWidth,
int maxCodewordWidth)
{
BoundingBox boundingBox = BoundingBox.Create(image, imageTopLeft, imageBottomLeft, imageTopRight, imageBottomRight);
if (boundingBox == null)
{
return(null);
}
DetectionResultRowIndicatorColumn leftRowIndicatorColumn = null;
DetectionResultRowIndicatorColumn rightRowIndicatorColumn = null;
DetectionResult detectionResult = null;
for (int i = 0; i < 2; i++)
{
if (imageTopLeft != null)
{
leftRowIndicatorColumn = getRowIndicatorColumn(image, boundingBox, imageTopLeft, true, minCodewordWidth, maxCodewordWidth);
}
if (imageTopRight != null)
{
rightRowIndicatorColumn = getRowIndicatorColumn(image, boundingBox, imageTopRight, false, minCodewordWidth, maxCodewordWidth);
}
detectionResult = merge(leftRowIndicatorColumn, rightRowIndicatorColumn);
if (detectionResult == null)
{
// TODO Based on Owen's Comments in <see cref="ZXing.ReaderException"/>, this method has been modified to continue silently
// if a barcode was not decoded where it was detected instead of throwing a new exception object.
return(null);
}
if (i == 0 && detectionResult.Box != null &&
(detectionResult.Box.MinY < boundingBox.MinY || detectionResult.Box.MaxY > boundingBox.MaxY))
{
boundingBox = detectionResult.Box;
}
else
{
detectionResult.Box = boundingBox;
break;
}
}
int maxBarcodeColumn = detectionResult.ColumnCount + 1;
detectionResult.DetectionResultColumns[0] = leftRowIndicatorColumn;
detectionResult.DetectionResultColumns[maxBarcodeColumn] = rightRowIndicatorColumn;
bool leftToRight = leftRowIndicatorColumn != null;
for (int barcodeColumnCount = 1; barcodeColumnCount <= maxBarcodeColumn; barcodeColumnCount++)
{
int barcodeColumn = leftToRight ? barcodeColumnCount : maxBarcodeColumn - barcodeColumnCount;
if (detectionResult.DetectionResultColumns[barcodeColumn] != null)
{
// This will be the case for the opposite row indicator column, which doesn't need to be decoded again.
continue;
}
DetectionResultColumn detectionResultColumn;
if (barcodeColumn == 0 || barcodeColumn == maxBarcodeColumn)
{
detectionResultColumn = new DetectionResultRowIndicatorColumn(boundingBox, barcodeColumn == 0);
}
else
{
detectionResultColumn = new DetectionResultColumn(boundingBox);
}
detectionResult.DetectionResultColumns[barcodeColumn] = detectionResultColumn;
int startColumn = -1;
int previousStartColumn = startColumn;
// TODO start at a row for which we know the start position, then detect upwards and downwards from there.
for (int imageRow = boundingBox.MinY; imageRow <= boundingBox.MaxY; imageRow++)
{
startColumn = getStartColumn(detectionResult, barcodeColumn, imageRow, leftToRight);
if (startColumn < 0 || startColumn > boundingBox.MaxX)
{
if (previousStartColumn == -1)
{
continue;
}
startColumn = previousStartColumn;
}
Codeword codeword = detectCodeword(image, boundingBox.MinX, boundingBox.MaxX, leftToRight,
startColumn, imageRow, minCodewordWidth, maxCodewordWidth);
if (codeword != null)
{
detectionResultColumn.setCodeword(imageRow, codeword);
previousStartColumn = startColumn;
minCodewordWidth = Math.Min(minCodewordWidth, codeword.Width);
maxCodewordWidth = Math.Max(maxCodewordWidth, codeword.Width);
}
}
}
return(createDecoderResult(detectionResult));
}
