iTextSharp ultra wide image in multiple pages horizontally

Question

I have a problem with iTextSharp. I have an image of 20000x1000 and I have to put it in a PDF with page size A1 horizontal. The tricky thing is that I need to adjust the height of the image to the PDF and print multiple pages wide in relation to the image.

I tried with this but it generates a PDF with a single page and the image adjusted both width and height.

Rectangle pageSize = PageSize.A1;
Document doc = new Document(pageSize.Rotate(), 10f, 10f, 10f, 10f);

PdfWriter writer = PdfWriter.GetInstance(doc, new FileStream(@"C:\TestFiles\Default.pdf", FileMode.Create));
doc.Open();

Image image = Image.GetInstance(@"C:\TestFiles\image.png");

PdfPTable table = new PdfPTable(1);
table.WidthPercentage = 100;
PdfPCell c = new PdfPCell(image, true);
c.Border = PdfPCell.NO_BORDER;
c.Padding = 5;
c.Image.ScaleAbsoluteHeight(pageSize.Height);
table.AddCell(c);
doc.Add(table);

doc.Close();

Thank you in advance for your help.

Bruno Lowagie Bruno Lowagie · Accepted Answer · 2016-11-30T16:59:44

Using a table is not the way to go for your requirement.

First let's take a look at how you can scale the image so that the height is adapted to the height of a rotated A1 document:

Image image = Image.GetInstance(@"C:\TestFiles\image.png");
image.ScaleToFit(image.ScaledWidth, PageSize.A1.Width);

The ScaleToFit() method scales an image so that it fits into a rectangle. In this case, we don't want the width to be reduced, so we define the width of that rectangle as equal to the width of the original image. We do want to scale the height so that it fits the height of a rotated A1 page. As we rotate the A1 page, we have to use PageSize.A1.Width instead of PageSize.A1.Height.

Suppose that you have an image that measures 500 x 1500, then the scaled image will have size 500 by 2000 because that image fits a rectangle of 500 by 1684.
Suppose that you have an image that measures 500 x 2000, then the scaled image will be 421 x 1684. The height will be reduced to fit the rotated A1 page, and the width will be reduced accordingly.
Suppose that you have an image of 5000 by 2000, then the scaled image will be 4210 x 1684.

Now we have to add the same image as many times as needed until the complete image is rendered. Note that the image bytes will only be stored once in the PDF: those bytes are reused for every page.

Float offset = 0;
while (offset <= img.ScaledWidth) {
    document.NewPage();
    img.SetAbsolutePosition(-offset, 0);
    document.Add(img);
    offset += PageSize.A1.HEIGHT;
}

What happens in the above code snippet? On the first page, we add the image at position (0, 0) which is means that the lower-left corner of the image will coincide with the lower left corner of the page.

If the image fits the page, e.g. in case the width was scaled smaller than the new offset (2384), no new page will be triggered. If the image doesn't fit the page (e.g. because the scaled width is 4210 which is greater than 2384) a new page will be created, and the same image will be added with a new offset (e.g. (-2384, 0)).

Suppose that the width of the scaled image is indeed 4210 and the width of the page is 2384, then the offset after a second page is added will be 4768. That is greater than 4210, so there will be no third page.

iTextSharp ultra wide image in multiple pages horizontally

1 Answers