/// <summary>
/// Build blocks via transitive closure.
/// </summary>
private static IEnumerable <TextBlock> GetLinesGroups(TextLine[] lines, double maxDist)
{
/**************************************************************************************************
* We want to measure the distance between two lines using the following method:
* We check if two lines are overlapping horizontally.
* If they are overlapping, we compute the middle point (new X coordinate) of the overlapping area.
* We finally compute the Euclidean distance between these two middle points.
* If the two lines are not overlapping, the distance is set to the max distance.
*
* /!\ WARNING: Given how FindIndexNearest() works, if 'maxDist' > 'line Height', the algo won't
* work as the FindIndexNearest() function will always pair the pivot with itself (the pivot's top
* point (distance = height) is closer than other lines' top point).
* -> Solution would be to find more than one nearest neighbours. Use KDTree?
**************************************************************************************************/
Func <PdfLine, PdfLine, double> euclidianOverlappingMiddleDistance = (l1, l2) =>
{
var left = Math.Max(l1.Point1.X, l2.Point1.X);
var d = (Math.Min(l1.Point2.X, l2.Point2.X) - left);
if (d < 0)
{
return(double.MaxValue); // not overlapping -> max distance
}
return(Distances.Euclidean(
new PdfPoint(left + d / 2, l1.Point1.Y),
new PdfPoint(left + d / 2, l2.Point1.Y)));
};
var groupedIndexes = ClusteringAlgorithms.SimpleTransitiveClosure(lines,
euclidianOverlappingMiddleDistance,
(pivot, candidate) => maxDist,
pivot => new PdfLine(pivot.BoundingBox.BottomLeft, pivot.BoundingBox.BottomRight),
candidate => new PdfLine(candidate.BoundingBox.TopLeft, candidate.BoundingBox.TopRight),
pivot => true, (pivot, candidate) => true).ToList();
for (int a = 0; a < groupedIndexes.Count(); a++)
{
yield return(new TextBlock(groupedIndexes[a].Select(i => lines[i]).ToList()));
}
}
private static IEnumerable <TextBlock> GetLinesGroups(TextLine[] lines, double maxDist, int maxDegreeOfParallelism)
{
/**************************************************************************************************
* We want to measure the distance between two lines using the following method:
* We check if two lines are overlapping horizontally.
* If they are overlapping, we compute the middle point (new X coordinate) of the overlapping area.
* We finally compute the Euclidean distance between these two middle points.
* If the two lines are not overlapping, the distance is set to the max distance.
**************************************************************************************************/
Func <PdfLine, PdfLine, double> euclidianOverlappingMiddleDistance = (l1, l2) =>
{
var left = Math.Max(l1.Point1.X, l2.Point1.X);
var d = (Math.Min(l1.Point2.X, l2.Point2.X) - left);
if (d < 0)
{
return(double.MaxValue); // not overlapping -> max distance
}
return(Distances.Euclidean(
new PdfPoint(left + d / 2, l1.Point1.Y),
new PdfPoint(left + d / 2, l2.Point1.Y)));
};
var groupedIndexes = ClusteringAlgorithms.ClusterNearestNeighbours(lines,
euclidianOverlappingMiddleDistance,
(pivot, candidate) => maxDist,
pivot => new PdfLine(pivot.BoundingBox.BottomLeft, pivot.BoundingBox.BottomRight),
candidate => new PdfLine(candidate.BoundingBox.TopLeft, candidate.BoundingBox.TopRight),
pivot => true, (pivot, candidate) => true,
maxDegreeOfParallelism).ToList();
for (int a = 0; a < groupedIndexes.Count(); a++)
{
yield return(new TextBlock(groupedIndexes[a].Select(i => lines[i]).ToList()));
}
}