How do I draw graphics to PDF using iText?

Question

I am trying to complete an example that draws graphics and writes them to PDF, but I keep getting errors that the PDF has no pages. if I add something simple with document.add() after opening it works fine, I just never see the graphics. Here is my code:

Document document = new Document();
PdfWriter writer = new PdfWriter();
response.setContentType("application/pdf");
response.setHeader("Content-Disposition",
    " attachment; filename=\"Design.pdf\"");

writer = PdfWriter.getInstance(document, response.getOutputStream());

document.open();    
PdfContentByte cb = writer.getDirectContent();
Graphics2D graphics2D = cb.createGraphics(36, 54);
graphics2D.drawString("Hello World", 36, 54);
graphics2D.dispose();   
document.close();

Do I have to do something else to add the graphic to the document or is my syntax incorrect?

Answer 1

I am not an expert in IText, but last week I tryed to draw some circles with it. So this is what I have noticed during my tests:

If you draw graphics, you must (or lets say I must when I tryed it) "wrap" the graphics commands in a section starting with saveState() and ending with restoreState(), es well as I needed to invoke fillStroke() -- if I do not invoke fillStroke() then nothing was drawn.

Example

private void circle(float x, float y, PdfWriter writer) {
    PdfContentByte canvas = writer.getDirectContent();

    canvas.saveState();
    canvas.setColorStroke(GrayColor.BLACK);
    canvas.setColorFill(GrayColor.BLACK);
    canvas.circle(x, y, 2);
    canvas.fillStroke();

    canvas.restoreState();
}

@Test
public void testPossition() throws DocumentException, IOException {
    OutputStream outputStream = FileUtil.openOutputStream("testPosition.pdf");
    //this is my personal file util, but it does not anything more
    //then creating a file and opening the file stream.

    Document document = new Document(PageSize.A4, 50, 50, 50, 50);
    PdfWriter writer = PdfWriter.getInstance(document, outputStream);
    document.open();

    markPosition(100, 100, writer);
    document.add(new Paragraph("Total: 595 x 842 -- 72pt (1 inch)"));

    document.close();
    outputStream.flush();
    outputStream.close();
}

private void markPosition(float x, float y, PdfWriter writer)
        throws DocumentException, IOException {
    placeChunck("x: " + x + " y: " + y, x, y, writer);
    circle(x, y, writer);
}

 private void placeChunck(String text, float x, float y, PdfWriter writer)
       throws DocumentException, IOException {
    PdfContentByte canvas = writer.getDirectContent();
    BaseFont font = BaseFont.createFont(BaseFont.HELVETICA,
                  BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
    canvas.saveState();
    canvas.beginText();
    canvas.moveText(x, y);
    canvas.setFontAndSize(font, 9);
    canvas.showText(text);
    canvas.endText();
    canvas.restoreState();
}

But PdfContentByte (canvas) has much more functions, for example rectangle.