ColumnText.ShowTextAligned() cuts off text after l

问题:

I have the following code to print a text onto a PDF document using iTextSharp:

canvas = stamper.GetOverContent(i)
watermarkFont = iTextSharp.text.pdf.BaseFont.CreateFont(iTextSharp.text.pdf.BaseFont.HELVETICA, iTextSharp.text.pdf.BaseFont.CP1252, iTextSharp.text.pdf.BaseFont.NOT_EMBEDDED)
watermarkFontColor = iTextSharp.text.BaseColor.RED
canvas.SetFontAndSize(watermarkFont, 11)
canvas.SetColorFill(watermarkFontColor)

Dim sText As String = "Line1" & vbCrLf & "Line2"
Dim nPhrase As New Phrase(sText)

ColumnText.ShowTextAligned(canvas, Element.ALIGN_TOP, nPhrase, 0, 50, 0)

However, only the first line ("Line1") is printed, the second line ("Line2") isn't.

Do I have to pass any flags to make that work?

回答1:

As documented, the ShowTextAligned() method can only be used to draw a single line. If you want to draw two lines, you have two options:

Option 1: use the method twice:

ColumnText.ShowTextAligned(canvas, Element.ALIGN_TOP, new Phrase("line 1"), 0, 50, 0)
ColumnText.ShowTextAligned(canvas, Element.ALIGN_TOP, new Phrase("line 2"), 0, 25, 0)

Option 2: use ColumnText in a different way:

ColumnText ct = new ColumnText(canvas);
ct.SetSimpleColumn(rect);
ct.AddElement(new Paragraph("line 1"));
ct.AddElement(new Paragraph("line 2"));
ct.Go();

In this code snippet, rect is of type Rectangle. It defines the area where you want to add the text. See How to add text in PdfContentByte rectangle using itextsharp?

回答2:

ColumnText.ShowTextAligned has been implemented as a short cut for the use case of adding a single line at a given position with given alignment. Confer the source code documentation:

/** Shows a line of text. Only the first line is written.
 * @param canvas where the text is to be written to
 * @param alignment the alignment
 * @param phrase the <CODE>Phrase</CODE> with the text
 * @param x the x reference position
 * @param y the y reference position
 * @param rotation the rotation to be applied in degrees counterclockwise
 */    
public static void ShowTextAligned(PdfContentByte canvas, int alignment, Phrase phrase, float x, float y, float rotation)

For more generic use cases please instantiate a ColumnText, set the content to draw and the outlines to draw in, and call Go().