Itext - Adding image in header - Empy Chunk - itext

Question

I'm trying to add an image to a PdfPageEventHelper class, as i saw in the original documentation, but when trying to add the new Chunk with the image to a Phrase, it's always empty...
This is my header and footer class
class PDFHeaderFooter extends PdfPageEventHelper {
public PDFHeaderFooter() throws BadElementException, MalformedURLException, IOException {
super();
}
Image image = Image.getInstance(imagesDir + "logo.png");
Phrase header = new Phrase(new Chunk(image, 0, 0, true));
int pagenumber;
public void onChapter(PdfWriter writer, Document document, float paragraphPosition, Paragraph title) {
pagenumber = 1;
}
public void onStartPage(PdfWriter writer, Document document) {
pagenumber++;
}
public void onEndPage(PdfWriter writer, Document document) {
Rectangle rect = writer.getBoxSize("art");
logger.debug(header.getContent());
ColumnText.showTextAligned(writer.getDirectContent(), Element.ALIGN_RIGHT, header, rect.getRight(),
rect.getTop(), 0);
ColumnText.showTextAligned(writer.getDirectContent(), Element.ALIGN_RIGHT,
new Phrase(String.format("pag. %d", pagenumber), fontSize9), (rect.getLeft() + rect.getRight()) / 2,
rect.getBottom() - 18, 0);
}
}
If i try to add the image in the document body, there is no problem at all, it's just when trying to add it the support class... is there another way?
thanks

Answer 1

The cause of the issue is that ColumnText.showTextAligned uses a ColumnText instance with a column rectangle only three units high.
The ColumnText code is designed to output one line of text at its preferred height (usually exceeding the 3 units) anyways in such a case. Most likely this is a hack to make ColumnText.showTextAligned work for a single line of text.
Unfortunately the ColumnText code at the same time scales down images in chunks to that 3 unit available column height, making them hardly more than dirt specks, or alternatively even drops them.
For phrases containing image chunks, therefore, one should not use the ColumnText.showTextAligned convenience methods but instead explicitly use a ColumnText instance with a sensible column rectangle height, e.g. replace
ColumnText.showTextAligned(writer.getDirectContent(), Element.ALIGN_RIGHT, header, rect.getRight(),
rect.getTop()-30, 0);
by
ColumnText ct = new ColumnText(writer.getDirectContent());
ct.setSimpleColumn(header, rect.getLeft(), rect.getTop(30), rect.getRight(), rect.getTop(), 2, Element.ALIGN_RIGHT);
try {
ct.go();
} catch (DocumentException e) {
throw new ExceptionConverter(e);
}
(AddHeaderImage page event listener method onEndPage)
It's not so much less convenient, after all, and one has more influence on the layout'ing details...