[
https://issues.apache.org/jira/browse/PDFBOX-5545?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Owen McGovern updated PDFBOX-5545:
----------------------------------
Description:
I process a lot of medical related PDF files with a lot of superscripts,
subscripts, out of order characters etc.
We tend to have trouble with the sortByPosition flag in PDFTextStripper.
If it's not enabled, we end up with characters which are out of order in some
PDFs.
If we do enable it it sometimes messes up superscript and subscript positions.
Can you expose a setter for the comparator instance, so that I can try to
correct it ? E.g.
{code:java}
private Comparator<TextPosition> textPositionComparator = new
TextPositionComparator();
/**
*
* @param newTextPositionComparator
*/
public void setTextPositionComparator(final Comparator<TextPosition>
newTextPositionComparator) {
this.textPositionComparator = newTextPositionComparator;
}
{code}
Then in the writePage() method, just use that comparator?
Users can then potentially inject their own comparator implementation in.
I want to try to implement a comparator that fixes sorting with
subscript/superscript tolerances, eg. something like this (in Kotlin and
completely untested so far... )
{code:java}
import mu.KLogging
import org.apache.pdfbox.text.TextPosition
import kotlin.math.absclass TextPositionSubscriptComparator :
Comparator<TextPosition>, KLogging() { override fun compare(pos1:
TextPosition, pos2: TextPosition): Int { val textDir =
pos1.dir.compareTo(pos2.dir)
return if (textDir != 0) {
textDir
} else {
val x1 = pos1.xDirAdj
val x2 = pos2.xDirAdj
val pos1YBottom = pos1.yDirAdj
val pos2YBottom = pos2.yDirAdj
val yDifference = abs(pos1YBottom - pos2YBottom) val
result = if (yDifference < 0.1f) {
x1.compareTo(x2)
} else {
val range1 = Pair(pos1.yDirAdj - OUT_OF_LINE_TOLERANCE,
pos1.yDirAdj + pos1.heightDir + OUT_OF_LINE_TOLERANCE)
val range2 = Pair(pos2.yDirAdj - OUT_OF_LINE_TOLERANCE,
pos2.yDirAdj + pos2.heightDir + OUT_OF_LINE_TOLERANCE) if
(range1.overlap(range2) || range2.overlap(range1)) {
x1.compareTo(x2)
} else {
if (pos1YBottom < pos2YBottom) -1 else 1
}
}// logger.info { "result = $result, [${pos1.unicode}],
x1=${pos1.x}, y1=${pos1.y} ---- [${pos2.unicode}], x2=${pos2.x}, y2=${pos1.y}"
} return result
} } companion object {
private const val OUT_OF_LINE_TOLERANCE = 2f
}
}/**
* Checks whether a numeric range overlaps with another
*/
fun Pair<Float, Float>.overlap(other: Pair<Float, Float>) =
!(first > other.second || second < other.first)
{code}
It could greatly help if the sorting comparator was configurable.
regards,
Owen
was:
I process a lot of medical related PDF files with a lot of superscripts,
subscripts, out of order characters etc.
We tend to have trouble with the sortByPosition flag in PDFTextStripper.
If it's not enabled, we end up with characters which are out of order in some
PDFs.
If we do enable it it sometimes messes up superscript and subscript positions.
Can you expose a setter for the comparator instance, so that I can try to
correct it ? E.g.
{code:java}
private Comparator<TextPosition> textPositionComparator = new
TextPositionComparator();
/**
*
* @param newTextPositionComparator
*/
public void setTextPositionComparator(final Comparator<TextPosition>
newTextPositionComparator) {
this.textPositionComparator = newTextPositionComparator;
}
{code}
Then in the writePage() method, just use that comparator?
Users can then potentially inject their own comparator implementation in.
I want to try to implement a comparator that fixes sorting with
subscript/superscript tolerances, eg. something like this (in Kotlin and
completely untested so far... )
{code:java}
import org.apache.pdfbox.text.TextPosition
import kotlin.math.abs
class TextPositionSubscriptComparator : Comparator<TextPosition> {
override fun compare(pos1: TextPosition, pos2: TextPosition): Int {
val textDir = pos1.dir.compareTo(pos2.dir)
return if (textDir != 0) {
textDir
} else {
val x1 = pos1.xDirAdj
val x2 = pos2.xDirAdj
val pos1YBottom = pos1.yDirAdj
val pos2YBottom = pos2.yDirAdj
val pos1YTop = pos1YBottom - pos1.heightDir
val pos2YTop = pos2YBottom - pos2.heightDir
val yDifference = abs(pos1YBottom - pos2YBottom)
// Superscript / subscript tolerance by ratio of the character
height
val overlap = if (pos1.heightDir > pos2.heightDir)
pos1.heightDir * INV_SIZE_RATIO_DIFFERENCE
else
pos2.heightDir * INV_SIZE_RATIO_DIFFERENCE
if ((yDifference.toDouble() < overlap || pos2YBottom >= pos1YTop)
&& pos2YBottom <= pos1YBottom || pos1YBottom in pos2YTop..pos2YBottom) {
x1.compareTo(x2)
} else {
if (pos1YBottom < pos2YBottom) -1 else 1
}
}
}
companion object {
private const val SIZE_RATIO_DIFFERENCE = 0.85f
private const val INV_SIZE_RATIO_DIFFERENCE = 1f - SIZE_RATIO_DIFFERENCE
}
}
{code}
It could greatly help if the sorting comparator was configurable.
regards,
Owen
> PDFTextStripper - Expose a setter for the TextPositionComparator
> ----------------------------------------------------------------
>
> Key: PDFBOX-5545
> URL: https://issues.apache.org/jira/browse/PDFBOX-5545
> Project: PDFBox
> Issue Type: Improvement
> Components: Text extraction
> Affects Versions: 3.0.0 PDFBox
> Reporter: Owen McGovern
> Priority: Major
>
> I process a lot of medical related PDF files with a lot of superscripts,
> subscripts, out of order characters etc.
> We tend to have trouble with the sortByPosition flag in PDFTextStripper.
> If it's not enabled, we end up with characters which are out of order in some
> PDFs.
> If we do enable it it sometimes messes up superscript and subscript positions.
> Can you expose a setter for the comparator instance, so that I can try to
> correct it ? E.g.
>
> {code:java}
> private Comparator<TextPosition> textPositionComparator = new
> TextPositionComparator();
> /**
> *
> * @param newTextPositionComparator
> */
> public void setTextPositionComparator(final Comparator<TextPosition>
> newTextPositionComparator) {
> this.textPositionComparator = newTextPositionComparator;
> }
> {code}
> Then in the writePage() method, just use that comparator?
>
> Users can then potentially inject their own comparator implementation in.
> I want to try to implement a comparator that fixes sorting with
> subscript/superscript tolerances, eg. something like this (in Kotlin and
> completely untested so far... )
>
> {code:java}
> import mu.KLogging
> import org.apache.pdfbox.text.TextPosition
> import kotlin.math.absclass TextPositionSubscriptComparator :
> Comparator<TextPosition>, KLogging() { override fun compare(pos1:
> TextPosition, pos2: TextPosition): Int { val textDir =
> pos1.dir.compareTo(pos2.dir)
> return if (textDir != 0) {
> textDir
> } else {
> val x1 = pos1.xDirAdj
> val x2 = pos2.xDirAdj
> val pos1YBottom = pos1.yDirAdj
> val pos2YBottom = pos2.yDirAdj
> val yDifference = abs(pos1YBottom - pos2YBottom) val
> result = if (yDifference < 0.1f) {
> x1.compareTo(x2)
> } else {
> val range1 = Pair(pos1.yDirAdj - OUT_OF_LINE_TOLERANCE,
> pos1.yDirAdj + pos1.heightDir + OUT_OF_LINE_TOLERANCE)
> val range2 = Pair(pos2.yDirAdj - OUT_OF_LINE_TOLERANCE,
> pos2.yDirAdj + pos2.heightDir + OUT_OF_LINE_TOLERANCE) if
> (range1.overlap(range2) || range2.overlap(range1)) {
> x1.compareTo(x2)
> } else {
> if (pos1YBottom < pos2YBottom) -1 else 1
> }
> }// logger.info { "result = $result,
> [${pos1.unicode}], x1=${pos1.x}, y1=${pos1.y} ---- [${pos2.unicode}],
> x2=${pos2.x}, y2=${pos1.y}" } return result
> } } companion object {
> private const val OUT_OF_LINE_TOLERANCE = 2f
> }
> }/**
> * Checks whether a numeric range overlaps with another
> */
> fun Pair<Float, Float>.overlap(other: Pair<Float, Float>) =
> !(first > other.second || second < other.first)
> {code}
>
> It could greatly help if the sorting comparator was configurable.
>
> regards,
> Owen
>
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