List of usage examples for org.apache.pdfbox.text TextPosition getIndividualWidths
public float[] getIndividualWidths()
From source file:com.repeatability.pdf.PDFTextStripper.java
License:Apache License
/** * This will print the text of the processed page to "output". It will estimate, based on the coordinates of the * text, where newlines and word spacings should be placed. The text will be sorted only if that feature was * enabled.//from w w w. j a v a 2 s. co m * * @throws IOException If there is an error writing the text. */ protected void writePage() throws IOException { float maxYForLine = MAX_Y_FOR_LINE_RESET_VALUE; float minYTopForLine = MIN_Y_TOP_FOR_LINE_RESET_VALUE; float endOfLastTextX = END_OF_LAST_TEXT_X_RESET_VALUE; float lastWordSpacing = LAST_WORD_SPACING_RESET_VALUE; float maxHeightForLine = MAX_HEIGHT_FOR_LINE_RESET_VALUE; PositionWrapper lastPosition = null; PositionWrapper lastLineStartPosition = null; boolean startOfPage = true; // flag to indicate start of page boolean startOfArticle; if (charactersByArticle.size() > 0) { writePageStart(); } for (List<TextPosition> textList : charactersByArticle) { if (getSortByPosition()) { TextPositionComparator comparator = new TextPositionComparator(); // because the TextPositionComparator is not transitive, but // JDK7+ enforces transitivity on comparators, we need to use // a custom quicksort implementation (which is slower, unfortunately). if (useCustomQuickSort) { QuickSort.sort(textList, comparator); } else { Collections.sort(textList, comparator); } } Iterator<TextPosition> textIter = textList.iterator(); startArticle(); startOfArticle = true; // Now cycle through to print the text. // We queue up a line at a time before we print so that we can convert // the line from presentation form to logical form (if needed). List<LineItem> line = new ArrayList<LineItem>(); textIter = textList.iterator(); // start from the beginning again // PDF files don't always store spaces. We will need to guess where we should add // spaces based on the distances between TextPositions. Historically, this was done // based on the size of the space character provided by the font. In general, this // worked but there were cases where it did not work. Calculating the average character // width and using that as a metric works better in some cases but fails in some cases // where the spacing worked. So we use both. NOTE: Adobe reader also fails on some of // these examples. // Keeps track of the previous average character width float previousAveCharWidth = -1; while (textIter.hasNext()) { TextPosition position = textIter.next(); PositionWrapper current = new PositionWrapper(position); String characterValue = position.getUnicode(); // Resets the average character width when we see a change in font // or a change in the font size if (lastPosition != null && (position.getFont() != lastPosition.getTextPosition().getFont() || position.getFontSize() != lastPosition.getTextPosition().getFontSize())) { previousAveCharWidth = -1; } float positionX; float positionY; float positionWidth; float positionHeight; // If we are sorting, then we need to use the text direction // adjusted coordinates, because they were used in the sorting. if (getSortByPosition()) { positionX = position.getXDirAdj(); positionY = position.getYDirAdj(); positionWidth = position.getWidthDirAdj(); positionHeight = position.getHeightDir(); } else { positionX = position.getX(); positionY = position.getY(); positionWidth = position.getWidth(); positionHeight = position.getHeight(); } // The current amount of characters in a word int wordCharCount = position.getIndividualWidths().length; // Estimate the expected width of the space based on the // space character with some margin. float wordSpacing = position.getWidthOfSpace(); float deltaSpace; if (wordSpacing == 0 || Float.isNaN(wordSpacing)) { deltaSpace = Float.MAX_VALUE; } else { if (lastWordSpacing < 0) { deltaSpace = wordSpacing * getSpacingTolerance(); } else { deltaSpace = (wordSpacing + lastWordSpacing) / 2f * getSpacingTolerance(); } } // Estimate the expected width of the space based on the average character width // with some margin. This calculation does not make a true average (average of // averages) but we found that it gave the best results after numerous experiments. // Based on experiments we also found that .3 worked well. float averageCharWidth; if (previousAveCharWidth < 0) { averageCharWidth = positionWidth / wordCharCount; } else { averageCharWidth = (previousAveCharWidth + positionWidth / wordCharCount) / 2f; } float deltaCharWidth = averageCharWidth * getAverageCharTolerance(); // Compares the values obtained by the average method and the wordSpacing method // and picks the smaller number. float expectedStartOfNextWordX = EXPECTED_START_OF_NEXT_WORD_X_RESET_VALUE; if (endOfLastTextX != END_OF_LAST_TEXT_X_RESET_VALUE) { if (deltaCharWidth > deltaSpace) { expectedStartOfNextWordX = endOfLastTextX + deltaSpace; } else { expectedStartOfNextWordX = endOfLastTextX + deltaCharWidth; } } if (lastPosition != null) { if (startOfArticle) { lastPosition.setArticleStart(); startOfArticle = false; } // RDD - Here we determine whether this text object is on the current // line. We use the lastBaselineFontSize to handle the superscript // case, and the size of the current font to handle the subscript case. // Text must overlap with the last rendered baseline text by at least // a small amount in order to be considered as being on the same line. // XXX BC: In theory, this check should really check if the next char is in // full range seen in this line. This is what I tried to do with minYTopForLine, // but this caused a lot of regression test failures. So, I'm leaving it be for // now if (!overlap(positionY, positionHeight, maxYForLine, maxHeightForLine)) { writeLine(normalize(line)); line.clear(); lastLineStartPosition = handleLineSeparation(current, lastPosition, lastLineStartPosition, maxHeightForLine); expectedStartOfNextWordX = EXPECTED_START_OF_NEXT_WORD_X_RESET_VALUE; maxYForLine = MAX_Y_FOR_LINE_RESET_VALUE; maxHeightForLine = MAX_HEIGHT_FOR_LINE_RESET_VALUE; minYTopForLine = MIN_Y_TOP_FOR_LINE_RESET_VALUE; } // test if our TextPosition starts after a new word would be expected to start if (expectedStartOfNextWordX != EXPECTED_START_OF_NEXT_WORD_X_RESET_VALUE && expectedStartOfNextWordX < positionX && // only bother adding a space if the last character was not a space lastPosition.getTextPosition().getUnicode() != null && !lastPosition.getTextPosition().getUnicode().endsWith(" ")) { line.add(LineItem.getWordSeparator()); } } if (positionY >= maxYForLine) { maxYForLine = positionY; } // RDD - endX is what PDF considers to be the x coordinate of the // end position of the text. We use it in computing our metrics below. endOfLastTextX = positionX + positionWidth; // add it to the list if (characterValue != null) { if (startOfPage && lastPosition == null) { writeParagraphStart();// not sure this is correct for RTL? } line.add(new LineItem(position)); } maxHeightForLine = Math.max(maxHeightForLine, positionHeight); minYTopForLine = Math.min(minYTopForLine, positionY - positionHeight); lastPosition = current; if (startOfPage) { lastPosition.setParagraphStart(); lastPosition.setLineStart(); lastLineStartPosition = lastPosition; startOfPage = false; } lastWordSpacing = wordSpacing; previousAveCharWidth = averageCharWidth; } // print the final line if (line.size() > 0) { writeLine(normalize(line)); writeParagraphEnd(); } endArticle(); } writePageEnd(); }