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https://issues.apache.org/jira/browse/PDFBOX-3885?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16110679#comment-16110679
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Andreas Lehmkühler commented on PDFBOX-3885:
--------------------------------------------
You are compariing apples with oranges or better two different coordinate
systems. PDFBox uses the lower left corner as 0,0 and poppler obviously the
upper left corner. Furthermore PDFBox provides the baseline coordinate of the
image and poppler the topline.
Which leads to the following pseudo formula
PDFBox_y = pageheight - poppler_y - imageheight
> Get wrong image location
> ------------------------
>
> Key: PDFBOX-3885
> URL: https://issues.apache.org/jira/browse/PDFBOX-3885
> Project: PDFBox
> Issue Type: Bug
> Components: Rendering
> Affects Versions: 2.0.7
> Environment: osx, java8
> Reporter: Sun Peter
> Assignee: Andreas Lehmkühler
> Labels: how-to
> Attachments: src.pdf
>
>
> I'm using below code to extract images to an XML file.
> {code:java}
> public class ImageExtractor extends PDFStreamEngine {
> private List<Image> images = new ArrayList<>();
> public ImageExtractor() {
> addOperator(new Concatenate());
> addOperator(new DrawObject());
> addOperator(new SetGraphicsStateParameters());
> addOperator(new Save());
> addOperator(new Restore());
> addOperator(new SetMatrix());
> }
> /**
> * This is used to handle an operation.
> *
> * @param operator The operation to perform.
> * @param operands The list of arguments.
> * @throws IOException If there is an error processing the operation.
> */
> @Override
> protected void processOperator(Operator operator, List<COSBase> operands)
> throws IOException {
> String operation = operator.getName();
> if ("Do".equals(operation)) {
> COSName objectName = (COSName) operands.get(0);
> PDXObject xobject = getResources().getXObject(objectName);
> if (xobject instanceof PDImageXObject) {
> PDImageXObject image = (PDImageXObject) xobject;
> String name = objectName.getName();
> String format = image.getSuffix();
> Matrix ctmNew =
> getGraphicsState().getCurrentTransformationMatrix();
> float imageWidth = ctmNew.getScalingFactorX();
> float imageHeight = ctmNew.getScalingFactorY();
> // position in user space units. 1 unit = 1/72 inch at 72 dpi
> float x = ctmNew.getTranslateX();
> float y = ctmNew.getTranslateY();
> ByteArrayOutputStream bos = new ByteArrayOutputStream();
> BufferedImage bufferedImage = image.getOpaqueImage();
> ImageIO.write(bufferedImage, format, bos);
> images.add(new Image(x, y, imageWidth, imageHeight, name,
> format, bos.toByteArray()));
> }
> } else {
> super.processOperator(operator, operands);
> }
> }
> public byte[] toZipFile(PDDocument doc) throws IOException {
> int pageNum = 0;
> StringBuilder builder = new StringBuilder("<?xml version=\"1.0\"
> encoding=\"UTF-8\"?>\n<document>\n");
> ByteArrayOutputStream bos = new ByteArrayOutputStream();
> ZipOutputStream zipOut = new ZipOutputStream(bos);
> try {
> for (PDPage page : doc.getPages()) {
> builder.append(String.format("<page width=\"%f\"
> height=\"%f\">\n", page.getBBox().getWidth(), page.getBBox().getHeight()));
> pageNum++;
> this.processPage(page);
> for (Image image : images) {
> byte[] data = image.getData();
> ZipEntry zipEntry = new ZipEntry(image.getName() + "." +
> image.getFormat());
> zipOut.putNextEntry(zipEntry);
> zipOut.write(data);
> builder.append(String.format("<image x=\"%f\" y=\"%f\"
> width=\"%f\" height=\"%f\" name=\"%s\" format=\"%s\"></image>\n",
> image.getX(), image.getY(), image.getWidth(), image.getHeight(),
> image.getName(), image.getFormat()));
> }
> builder.append("</page>\n");
> }
> builder.append("</document>");
> System.out.println(builder);
> ZipEntry xmlFile = new ZipEntry("images.xml");
> zipOut.putNextEntry(xmlFile);
>
> zipOut.write(builder.toString().getBytes(Charset.defaultCharset()));
> } finally {
> zipOut.close();
> }
> return bos.toByteArray();
> }
> }
> {code}
> Output is below. the y location is wrong. it should be 434.
> {code:xml}
> <document>
> <page width="595.000000" height="842.000000">
> <image x="48.000000" y="108.000000" width="315.000000" height="300.000000"
> name="Im12" format="jpg"></image>
> </page>
> </document>
> {code}
> I got the right output with poppler.
> {code:xml}
> <image top="434" left="48" width="315" height="300" src="src-1_1.jpg"/>
> {code}
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