Im looking for the easiest way to implement a java solution which is quiet similar to the output of
pdftotext -layout FILE
on linux machines. (And of course it should be cheap as well)
I just tried some code snippets of IText, PDFBox and PDFTextStream. The most accurate solution so far is PDFTextStream which uses the VisualOutputTarget to get a great representation of my file.
So my column layout is recognized correct and I'm able to work with it. But there should be also a solution for IText, or?
Every easy snippet I found produces plain ordered strings which are a mess (mess up row/column/lines). Is there any solution which might be easier and may not involve a own Strategy? Or is there a open Source strategy which i can use?
// I followed the instructions of mkl and have written and own strategy object as follows:
package com.test.pdfextractiontest.itext;
import ...
public class MyLocationTextExtractionStrategy implements TextExtractionStrategy {
/** set to true for debugging */
static boolean DUMP_STATE = false;
/** a summary of all found text */
private final List<TextChunk> locationalResult = new ArrayList<TextChunk>();
public MyLocationTextExtractionStrategy() {
}
@Override
public void beginTextBlock() {
}
@Override
public void endTextBlock() {
}
private boolean startsWithSpace(final String str) {
if (str.length() == 0) {
return false;
}
return str.charAt(0) == ' ';
}
private boolean endsWithSpace(final String str) {
if (str.length() == 0) {
return false;
}
return str.charAt(str.length() - 1) == ' ';
}
private List<TextChunk> filterTextChunks(final List<TextChunk> textChunks, final TextChunkFilter filter) {
if (filter == null) {
return textChunks;
}
final List<TextChunk> filtered = new ArrayList<TextChunk>();
for (final TextChunk textChunk : textChunks) {
if (filter.accept(textChunk)) {
filtered.add(textChunk);
}
}
return filtered;
}
protected boolean isChunkAtWordBoundary(final TextChunk chunk, final TextChunk previousChunk) {
final float dist = chunk.distanceFromEndOf(previousChunk);
if (dist < -chunk.getCharSpaceWidth() || dist > chunk.getCharSpaceWidth() / 2.0f) {
return true;
}
return false;
}
public String getResultantText(final TextChunkFilter chunkFilter) {
if (DUMP_STATE) {
dumpState();
}
final List<TextChunk> filteredTextChunks = filterTextChunks(this.locationalResult, chunkFilter);
Collections.sort(filteredTextChunks);
final StringBuffer sb = new StringBuffer();
TextChunk lastChunk = null;
for (final TextChunk chunk : filteredTextChunks) {
if (lastChunk == null) {
sb.append(chunk.text);
} else {
if (chunk.sameLine(lastChunk)) {
if (isChunkAtWordBoundary(chunk, lastChunk) && !startsWithSpace(chunk.text)
&& !endsWithSpace(lastChunk.text)) {
sb.append(' ');
}
final Float dist = chunk.distanceFromEndOf(lastChunk)/3;
for(int i = 0; i<Math.round(dist); i++) {
sb.append(' ');
}
sb.append(chunk.text);
} else {
sb.append('\n');
sb.append(chunk.text);
}
}
lastChunk = chunk;
}
return sb.toString();
}
eturn a String with the resulting text. */ @Override public String getResultantText() {
return getResultantText(null);
}
private void dumpState() {
for (final TextChunk location : this.locationalResult) {
location.printDiagnostics();
System.out.println();
}
}
@Override
public void renderText(final TextRenderInfo renderInfo) {
LineSegment segment = renderInfo.getBaseline();
if (renderInfo.getRise() != 0) {
final Matrix riseOffsetTransform = new Matrix(0, -renderInfo.getRise());
segment = segment.transformBy(riseOffsetTransform);
}
final TextChunk location =
new TextChunk(renderInfo.getText(), segment.getStartPoint(), segment.getEndPoint(),
renderInfo.getSingleSpaceWidth(),renderInfo);
this.locationalResult.add(location);
}
public static class TextChunk implements Comparable<TextChunk> {
/** the text of the chunk */
private final String text;
/** the starting location of the chunk */
private final Vector startLocation;
/** the ending location of the chunk */
private final Vector endLocation;
/** unit vector in the orientation of the chunk */
private final Vector orientationVector;
/** the orientation as a scalar for quick sorting */
private final int orientationMagnitude;
private final TextRenderInfo info;
private final int distPerpendicular;
private final float distParallelStart;
private final float distParallelEnd;
/** the width of a single space character in the font of the chunk */
private final float charSpaceWidth;
public TextChunk(final String string, final Vector startLocation, final Vector endLocation,
final float charSpaceWidth,final TextRenderInfo ri) {
this.text = string;
this.startLocation = startLocation;
this.endLocation = endLocation;
this.charSpaceWidth = charSpaceWidth;
this.info = ri;
Vector oVector = endLocation.subtract(startLocation);
if (oVector.length() == 0) {
oVector = new Vector(1, 0, 0);
}
this.orientationVector = oVector.normalize();
this.orientationMagnitude =
(int) (Math.atan2(this.orientationVector.get(Vector.I2), this.orientationVector.get(Vector.I1)) * 1000);
final Vector origin = new Vector(0, 0, 1);
this.distPerpendicular = (int) startLocation.subtract(origin).cross(this.orientationVector).get(Vector.I3);
this.distParallelStart = this.orientationVector.dot(startLocation);
this.distParallelEnd = this.orientationVector.dot(endLocation);
}
public Vector getStartLocation() {
return this.startLocation;
}
public Vector getEndLocation() {
return this.endLocation;
}
public String getText() {
return this.text;
}
public float getCharSpaceWidth() {
return this.charSpaceWidth;
}
private void printDiagnostics() {
System.out.println("Text (@" + this.startLocation + " -> " + this.endLocation + "): " + this.text);
System.out.println("orientationMagnitude: " + this.orientationMagnitude);
System.out.println("distPerpendicular: " + this.distPerpendicular);
System.out.println("distParallel: " + this.distParallelStart);
}
public boolean sameLine(final TextChunk as) {
if (this.orientationMagnitude != as.orientationMagnitude) {
return false;
}
if (this.distPerpendicular != as.distPerpendicular) {
return false;
}
return true;
}
public float distanceFromEndOf(final TextChunk other) {
final float distance = this.distParallelStart - other.distParallelEnd;
return distance;
}
public float myDistanceFromEndOf(final TextChunk other) {
final float distance = this.distParallelStart - other.distParallelEnd;
return distance;
}
@Override
public int compareTo(final TextChunk rhs) {
if (this == rhs) {
return 0; // not really needed, but just in case
}
int rslt;
rslt = compareInts(this.orientationMagnitude, rhs.orientationMagnitude);
if (rslt != 0) {
return rslt;
}
rslt = compareInts(this.distPerpendicular, rhs.distPerpendicular);
if (rslt != 0) {
return rslt;
}
return Float.compare(this.distParallelStart, rhs.distParallelStart);
}
private static int compareInts(final int int1, final int int2) {
return int1 == int2 ? 0 : int1 < int2 ? -1 : 1;
}
public TextRenderInfo getInfo() {
return this.info;
}
}
@Override
public void renderImage(final ImageRenderInfo renderInfo) {
// do nothing
}
public static interface TextChunkFilter {
public boolean accept(TextChunk textChunk);
}
}
As you can see most is the same as the original class. i just added this :
final Float dist = chunk.distanceFromEndOf(lastChunk)/3;
for(int i = 0; i<Math.round(dist); i++) {
sb.append(' ');
}
to the getResultantText Method to extend the gaps with spaces. But here is the problem:
the distance seems to be inaccurate or inexact. the result looks like
this:
does anyone have an idea how to calculate a better or value for the distance? i think its because the original font type is ArialMT and my editor is in courier, but to work with this sheet its recommended that i can split the table on the correct place to get my data. thats difficult due the floating start and end of an value usw.
:-/
