Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // kwa package com.repeatability.pdf; import org.apache.pdfbox.text.*; import java.io.InputStream; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.pdfbox.contentstream.PDFStreamEngine; import org.apache.pdfbox.pdmodel.PDPage; import org.apache.pdfbox.pdmodel.font.encoding.GlyphList; import org.apache.pdfbox.pdmodel.common.PDRectangle; import org.apache.pdfbox.pdmodel.font.PDCIDFont; import org.apache.pdfbox.pdmodel.font.PDCIDFontType2; import org.apache.pdfbox.pdmodel.font.PDFont; import org.apache.pdfbox.pdmodel.font.PDSimpleFont; import org.apache.pdfbox.pdmodel.font.PDTrueTypeFont; import org.apache.pdfbox.pdmodel.font.PDType0Font; import org.apache.pdfbox.pdmodel.font.PDType3Font; import org.apache.pdfbox.pdmodel.graphics.state.PDGraphicsState; import java.io.IOException; import org.apache.fontbox.ttf.TrueTypeFont; import org.apache.fontbox.util.BoundingBox; import org.apache.pdfbox.util.Matrix; import org.apache.pdfbox.util.Vector; import org.apache.pdfbox.contentstream.operator.DrawObject; import org.apache.pdfbox.contentstream.operator.state.Concatenate; import org.apache.pdfbox.contentstream.operator.state.Restore; import org.apache.pdfbox.contentstream.operator.state.Save; import org.apache.pdfbox.contentstream.operator.state.SetGraphicsStateParameters; import org.apache.pdfbox.contentstream.operator.state.SetMatrix; import org.apache.pdfbox.contentstream.operator.text.BeginText; import org.apache.pdfbox.contentstream.operator.text.EndText; import org.apache.pdfbox.contentstream.operator.text.SetFontAndSize; import org.apache.pdfbox.contentstream.operator.text.SetTextHorizontalScaling; import org.apache.pdfbox.contentstream.operator.text.ShowTextAdjusted; import org.apache.pdfbox.contentstream.operator.text.ShowTextLine; import org.apache.pdfbox.contentstream.operator.text.ShowTextLineAndSpace; import org.apache.pdfbox.contentstream.operator.text.MoveText; import org.apache.pdfbox.contentstream.operator.text.MoveTextSetLeading; import org.apache.pdfbox.contentstream.operator.text.NextLine; import org.apache.pdfbox.contentstream.operator.text.SetCharSpacing; import org.apache.pdfbox.contentstream.operator.text.SetTextLeading; import org.apache.pdfbox.contentstream.operator.text.SetTextRenderingMode; import org.apache.pdfbox.contentstream.operator.text.SetTextRise; import org.apache.pdfbox.contentstream.operator.text.SetWordSpacing; import org.apache.pdfbox.contentstream.operator.text.ShowText; import org.apache.pdfbox.pdmodel.font.PDFontDescriptor; /** * PDFStreamEngine subclass for advanced processing of text via TextPosition. * * @see org.apache.pdfbox.text.TextPosition * @author Ben Litchfield * @author John Hewson */ // kwa public! public class PDFTextStreamEngine extends PDFStreamEngine { private static final Log LOG = LogFactory.getLog(PDFTextStreamEngine.class); private int pageRotation; private PDRectangle pageSize; private Matrix translateMatrix; private final GlyphList glyphList; /** * Constructor. */ PDFTextStreamEngine() throws IOException { addOperator(new BeginText()); addOperator(new Concatenate()); addOperator(new DrawObject()); // special text version addOperator(new EndText()); addOperator(new SetGraphicsStateParameters()); addOperator(new Save()); addOperator(new Restore()); addOperator(new NextLine()); addOperator(new SetCharSpacing()); addOperator(new MoveText()); addOperator(new MoveTextSetLeading()); addOperator(new SetFontAndSize()); addOperator(new ShowText()); addOperator(new ShowTextAdjusted()); addOperator(new SetTextLeading()); addOperator(new SetMatrix()); addOperator(new SetTextRenderingMode()); addOperator(new SetTextRise()); addOperator(new SetWordSpacing()); addOperator(new SetTextHorizontalScaling()); addOperator(new ShowTextLine()); addOperator(new ShowTextLineAndSpace()); // load additional glyph list for Unicode mapping String path = "org/apache/pdfbox/resources/glyphlist/additional.txt"; InputStream input = GlyphList.class.getClassLoader().getResourceAsStream(path); glyphList = new GlyphList(GlyphList.getAdobeGlyphList(), input); } /** * This will initialise and process the contents of the stream. * * @param page the page to process * @throws java.io.IOException if there is an error accessing the stream. */ @Override public void processPage(PDPage page) throws IOException { this.pageRotation = page.getRotation(); this.pageSize = page.getCropBox(); if (pageSize.getLowerLeftX() == 0 && pageSize.getLowerLeftY() == 0) { translateMatrix = null; } else { // translation matrix for cropbox translateMatrix = Matrix.getTranslateInstance(-pageSize.getLowerLeftX(), -pageSize.getLowerLeftY()); } super.processPage(page); } /** * This method was originally written by Ben Litchfield for PDFStreamEngine. */ @Override protected void showGlyph(Matrix textRenderingMatrix, PDFont font, int code, String unicode, Vector displacement) throws IOException { // // legacy calculations which were previously in PDFStreamEngine // PDGraphicsState state = getGraphicsState(); Matrix ctm = state.getCurrentTransformationMatrix(); float fontSize = state.getTextState().getFontSize(); float horizontalScaling = state.getTextState().getHorizontalScaling() / 100f; Matrix textMatrix = getTextMatrix(); BoundingBox bbox = font.getBoundingBox(); if (bbox.getLowerLeftY() < Short.MIN_VALUE) { // PDFBOX-2158 and PDFBOX-3130 // files by Salmat eSolutions / ClibPDF Library bbox.setLowerLeftY(-(bbox.getLowerLeftY() + 65536)); } // 1/2 the bbox is used as the height todo: why? float glyphHeight = bbox.getHeight() / 2; // sometimes the bbox has very high values, but CapHeight is OK PDFontDescriptor fontDescriptor = font.getFontDescriptor(); if (fontDescriptor != null) { float capHeight = fontDescriptor.getCapHeight(); if (capHeight != 0 && capHeight < glyphHeight) { glyphHeight = capHeight; } } // transformPoint from glyph space -> text space float height; if (font instanceof PDType3Font) { height = font.getFontMatrix().transformPoint(0, glyphHeight).y; } else { height = glyphHeight / 1000; } float displacementX = displacement.getX(); // the sorting algorithm is based on the width of the character. As the displacement // for vertical characters doesn't provide any suitable value for it, we have to // calculate our own if (font.isVertical()) { displacementX = font.getWidth(code) / 1000; // there may be an additional scaling factor for true type fonts TrueTypeFont ttf = null; if (font instanceof PDTrueTypeFont) { ttf = ((PDTrueTypeFont) font).getTrueTypeFont(); } else if (font instanceof PDType0Font) { PDCIDFont cidFont = ((PDType0Font) font).getDescendantFont(); if (cidFont instanceof PDCIDFontType2) { ttf = ((PDCIDFontType2) cidFont).getTrueTypeFont(); } } if (ttf != null && ttf.getUnitsPerEm() != 1000) { displacementX *= 1000f / ttf.getUnitsPerEm(); } } // (modified) combined displacement, this is calculated *without* taking the character // spacing and word spacing into account, due to legacy code in TextStripper float tx = displacementX * fontSize * horizontalScaling; float ty = displacement.getY() * fontSize; // (modified) combined displacement matrix Matrix td = Matrix.getTranslateInstance(tx, ty); // (modified) text rendering matrix Matrix nextTextRenderingMatrix = td.multiply(textMatrix).multiply(ctm); // text space -> device space float nextX = nextTextRenderingMatrix.getTranslateX(); float nextY = nextTextRenderingMatrix.getTranslateY(); // (modified) width and height calculations float dxDisplay = nextX - textRenderingMatrix.getTranslateX(); float dyDisplay = height * textRenderingMatrix.getScalingFactorY(); // // start of the original method // // Note on variable names. There are three different units being used in this code. // Character sizes are given in glyph units, text locations are initially given in text // units, and we want to save the data in display units. The variable names should end with // Text or Disp to represent if the values are in text or disp units (no glyph units are // saved). float glyphSpaceToTextSpaceFactor = 1 / 1000f; if (font instanceof PDType3Font) { glyphSpaceToTextSpaceFactor = font.getFontMatrix().getScaleX(); } float spaceWidthText = 0; try { // to avoid crash as described in PDFBOX-614, see what the space displacement should be spaceWidthText = font.getSpaceWidth() * glyphSpaceToTextSpaceFactor; } catch (Throwable exception) { LOG.warn(exception, exception); } if (spaceWidthText == 0) { spaceWidthText = font.getAverageFontWidth() * glyphSpaceToTextSpaceFactor; // the average space width appears to be higher than necessary so make it smaller spaceWidthText *= .80f; } if (spaceWidthText == 0) { spaceWidthText = 1.0f; // if could not find font, use a generic value } // the space width has to be transformed into display units float spaceWidthDisplay = spaceWidthText * textRenderingMatrix.getScalingFactorX(); // use our additional glyph list for Unicode mapping unicode = font.toUnicode(code, glyphList); // when there is no Unicode mapping available, Acrobat simply coerces the character code // into Unicode, so we do the same. Subclasses of PDFStreamEngine don't necessarily want // this, which is why we leave it until this point in PDFTextStreamEngine. if (unicode == null) { if (font instanceof PDSimpleFont) { char c = (char) code; unicode = new String(new char[] { c }); } else { // Acrobat doesn't seem to coerce composite font's character codes, instead it // skips them. See the "allah2.pdf" TestTextStripper file. return; } } // adjust for cropbox if needed Matrix translatedTextRenderingMatrix; if (translateMatrix == null) { translatedTextRenderingMatrix = textRenderingMatrix; } else { translatedTextRenderingMatrix = Matrix.concatenate(translateMatrix, textRenderingMatrix); nextX -= pageSize.getLowerLeftX(); nextY -= pageSize.getLowerLeftY(); } processTextPosition(new TextPosition(pageRotation, pageSize.getWidth(), pageSize.getHeight(), translatedTextRenderingMatrix, nextX, nextY, dyDisplay, dxDisplay, spaceWidthDisplay, unicode, new int[] { code }, font, fontSize, (int) (fontSize * textMatrix.getScalingFactorX()))); } /** * A method provided as an event interface to allow a subclass to perform some specific * functionality when text needs to be processed. * * @param text The text to be processed. */ protected void processTextPosition(TextPosition text) { // subclasses can override to provide specific functionality } }