How can I change page origin? - Image inserted at unexpected location - itext

Question

Using iText 7.1.9 java edition, I am attempting to add an image to a PDF at a fixed/absolute location, if the PDF is not landscape then I rotate it 90 degrees, however, once the page is rotated the origin point (was bottom left corner) also rotates (now at the top left corner and rotated 90 degrees), so when I insert the image it ends up rotated and uses the wrong origin point. See the two example PDF linked below for a visual of what is happening.
Is there any way to change a page origin point to the bottom left corner after a page is rotated? Is there a better way to rotate a page than using PdfDocument.getPage(p).setRotation?
Should I simply rotate the image and do some math to work out the new location for any additional elements? I have attempted rotating the image using imageData.setRotation(90) but it appears to do nothing.
The following are the inputs using the PDF attached at the bottom of this question:
//String pdfPath = "before_expected.pdf";
//String pdfDest = "after_expected.pdf";
//Or
String pdfPath = "before_unexpected.pdf";
String pdfDest = "after_unexpected.pdf";
The following is my code to rotate pages and add the image:
//Open existing PDF
FileInputStream inputStream = new FileInputStream(pdfPath);
PdfReader reader = new PdfReader(inputStream).setUnethicalReading(true);
//Create new PDF
FileOutputStream outputStream = new FileOutputStream(pdfDest);
PdfWriter writer = new PdfWriter(outputStream);
PdfDocument pdfDocument = new PdfDocument(reader, writer);
//Load sample image
ImageData imageData = ImageDataFactory.create("C:/sample_image.png");
Image image = new Image(imageData);
//Get root element of PDF
Document document = new Document(pdfDocument);
//Get orientation
Rectangle pageSize = pdfDocument.getPage(1).getPageSize();
System.out.println("Original rotation " + pdfDocument.getPage(1).getRotation() + System.lineSeparator() + pageSize.toString());
//Rotate 90 if page is not landscape - placeholder
if (pageSize.getHeight() > pageSize.getWidth())
{
pdfDocument.getPage(1).setRotation(pdfDocument.getPage(1).getRotation() + 90);
}
//Find page size
Rectangle currentPageSize = pdfDocument.getPage(1).getPageSizeWithRotation();
//Locate image 40% across page and 20% up page
float absoluteXpos = currentPageSize.getWidth() * 0.4f;
float absoluteYpos = currentPageSize.getHeight() * 0.2f;
System.out.println("Image location from origin: " + absoluteXpos + ", "+absoluteYpos);
//Add image
image.setFixedPosition(absoluteXpos, absoluteYpos);
document.add(image);
//Removed code to close any tidy up
document.close();
The output from the second PDF (before_unexpected.pdf) shows that it is rotated, but as mentioned above, rotating the page further appears to make no difference for adding additional content:
Original rotation 90
Rectangle: 842.0x1191.0
Image location from origin: 336.80002, 238.2
Here are the PDF files I used for testing:
The first two images show expected/desired behaviour, the last two show how the image is inserted in the wrong spot (based on the incorrect origin/rotation).
Click here for the original file for the first pdf
Click here for the processed file for the first pdf
Click here for the original file for the second pdf
Click here for the processed file for the second pdf

Answer 1

First of all, when determining whether the current page is not landscape (if (pageSize.getHeight() > pageSize.getWidth())) you should already use getPageSizeWithRotation() instead of simply getPageSize(). You use this method later on in the code and you should have used it at an earlier point as well.
Secondly, if you want to add some content to the fixed position independent of the page rotation, you can use the following instruction before adding the content:
pdfDocument.getPage(1).setIgnorePageRotationForContent(true);
The complete code:
//Open existing PDF
FileInputStream inputStream = new FileInputStream("C:/in.pdf");
PdfReader reader = new PdfReader(inputStream).setUnethicalReading(true);
//Create new PDF
FileOutputStream outputStream = new FileOutputStream("C:/Users/Alexey/Desktop/exp.pdf");
PdfWriter writer = new PdfWriter(outputStream);
PdfDocument pdfDocument = new PdfDocument(reader, writer);
//Load sample image
ImageData imageData = ImageDataFactory.create("C:/sample_image.png");
Image image = new Image(imageData);
//Get root element of PDF
pdfDocument.getPage(1).setIgnorePageRotationForContent(true);
Document document = new Document(pdfDocument);
//Get orientation
Rectangle pageSize = pdfDocument.getPage(1).getPageSizeWithRotation();
System.out.println("Original rotation " + pdfDocument.getPage(1).getRotation() + System.lineSeparator() + pageSize.toString());
//Rotate 90 if page is not landscape - placeholder
if (pageSize.getHeight() > pageSize.getWidth())
{
pdfDocument.getPage(1).setRotation(pdfDocument.getPage(1).getRotation() + 90);
}
//Find page size
Rectangle currentPageSize = pdfDocument.getPage(1).getPageSizeWithRotation();
//Locate image 40% across page and 20% up page
float absoluteXpos = currentPageSize.getWidth() * 0.4f;
float absoluteYpos = currentPageSize.getHeight() * 0.2f;
System.out.println("Image location from origin: " + absoluteXpos + ", "+absoluteYpos);
//Add image
image.setFixedPosition(absoluteXpos, absoluteYpos);
document.add(image);
//Removed code to close any tidy up
document.close();
It gives me same result for both input files: