iText: Different table rows with different cell/column widths - pdf-generation

Question

How to create with Java a table with three rows as follows:
First row has one cell 100% entire table width
Second row has first from the left cell width 50mm, and second 20mm and third 30mm which in total is 100% of table width
Third row has first from the left cell width 30mm, and second 50mm and third 10mm which in total is 90% of table width
How would the code from the iText look like?

Answer 1

So you want to use iText to create a table that looks like this:
The PDF in the screen shot was created using the TableMeasurements example. The resulting PDF can also be downloaded for inspection: table_measurements.pdf
The first thing that jumps to the eye when looking at this screen shot is the fact that the table doesn't look "complete". This means that we will have to complete the table the way I already explained on SO yesterday (and many times before that): Why the 2nd row of table won't be written? (which was actually a duplicate of How to generate pdf if our column less than the declared table column and ItextSharp, number of Cells not dividable by the length of the row and Odd Numbered Cell Not Added To Pdf and PdfTable: last cell is not visible and ...)
In the comment section, I was asked:
How can I complete row with cells with no border?
I answered:
Use table.getDefaultCell().setBorder(Rectangle.NO_BORDER);
Note that PdfPCell.NO_BORDER also works as PdfPCell extends the Rectangle class.
In your case, we'd have something like this:
public void createPdf(String dest) throws IOException, DocumentException {
Document document = new Document();
PdfWriter.getInstance(document, new FileOutputStream(dest));
document.open();
PdfPTable table = new PdfPTable(10);
table.setTotalWidth(Utilities.millimetersToPoints(100));
table.setLockedWidth(true);
table.getDefaultCell().setBorder(PdfPCell.NO_BORDER);
table.addCell(getCell(10));
table.addCell(getCell(5));
table.addCell(getCell(3));
table.addCell(getCell(2));
table.addCell(getCell(3));
table.addCell(getCell(5));
table.addCell(getCell(1));
table.completeRow();
document.add(table);
document.close();
}
To make the example more realistic, I created a table with an exact width of 100 mm. For the width to be acknowledged, I lock the width. As already explained, I make sure that default cells have no border. After adding all the cells with the different widths (10 cm, 5 cm, 3 cm, 2 cm, 3 cm, 5 cm, 1 cm), I complete the row.
What does the getCell() method look like, you might wonder. This was already answered by Amedee in the comments (which for some reason you ignored):
private PdfPCell getCell(int cm) {
PdfPCell cell = new PdfPCell();
cell.setColspan(cm);
cell.setUseAscender(true);
cell.setUseDescender(true);
Paragraph p = new Paragraph(
String.format("%smm", 10 * cm),
new Font(Font.FontFamily.HELVETICA, 8));
p.setAlignment(Element.ALIGN_CENTER);
cell.addElement(p);
return cell;
}
We create a PdfPCell and we set the colspan to reflect the width in cm. I added some more fancy stuff. I didn't use any functionality in this example that isn't explained on the official web site or on StackOverflow.
For more rowspan and colspan examples, please take a look at the Colspan and rowspan section in the official documentation.