Java Stamp on certain location of pdf using iText

Question

I am making a web application using Javascript for the front end and this is how it works:

I start the application and it opens a web page via my browser.
It displays a PDF page obtained from my directory.
I have the option to click on a stamp and drag and move around the pdf and place where ever I want.
When I'm done, I could click Save and it automatically saves the pdf file in my directory.
I can open the pdf file in my folder to view the updated PDF along with the stamp added.

The problem is when I open the PDF file to view, the positioning is not identical to the positioning of the stamp in the web browser.

   

window.dragMoveListener = dragMoveListener;

    interact('.signer-box')
        .draggable({
            onmove: dragMoveListener,
            inertia: true,
            autoScroll: true,
            restrict: {
                elementRect: {top: 0, left: 0, bottom: 1, right: 1}
            }
        })
        .resizable({
            onmove: resizeMoveListener,
            inertia: true,
            edges: {left: true, right: true, bottom: true, top: true}
        })

function dragMoveListener(event) {
    var target = event.target;
    var x = (parseFloat(target.getAttribute('data-x')) || 0) + event.dx;
    var y = (parseFloat(target.getAttribute('data-y')) || 0) + event.dy;
    target.style.webkitTransform = target.style.transform = 'translate(' + x + 'px, ' + y + 'px)';
    target.setAttribute('data-x', x);
    target.setAttribute('data-y', y);
    
    computeSignerBoxPosition();
}

function resizeMoveListener(event) {
    var target = event.target;
    var x = (parseFloat(target.getAttribute('data-x')) || 0);
    var y = (parseFloat(target.getAttribute('data-y')) || 0);
    x += event.deltaRect.left;
    y += event.deltaRect.top;

    target.style.width = event.rect.width + 'px';
    target.style.height = event.rect.height + 'px';
    target.style.webkitTransform = target.style.transform = 'translate(' + x + 'px,' + y + 'px)';
    target.setAttribute('data-x', x);
    target.setAttribute('data-y', y);
    
    computeSignerBoxPosition();
}

function computeSignerBoxPosition() {
    var $signatureBox = $('.signer-box');
    var sbDataX = parseFloat($signatureBox.attr('data-x'));
    var sbDataY = parseFloat($signatureBox.attr('data-y'));
    var sbOuterWidth = $signatureBox.outerWidth();
    var sbOuterHeight = $signatureBox.outerHeight();

    var w = $('#pdf-page').width();
    var h = $('#pdf-page').height();
    
    var top = sbDataX / w;
    var left = sbDataY / h;
    var width = sbOuterWidth / w;
    var height = sbOuterHeight / h;

    document.getElementById("widthValue").value = width;
    document.getElementById("heightValue").value = height;
    document.getElementById("coorX").value = top;
    document.getElementById("coorY").value = left;
}

@charset "UTF-8";

#content{
    text-align: center;
}

#pdf-container {
    display: inline-block;
    width: 100%;
    user-select: none;
}

#pdf-page {
    width: 100%;
}

.signer-box {
    background: url('../images/pen_icon.png') #29e no-repeat 50% 50%;
    background-size: 50%;
    color: white;
    font-size: 20px;
    font-family: sans-serif;
    border-radius: 8px;
    width: 180px;
    height: 150px;
    position:absolute;
    opacity: .8;
    box-sizing: border-box;
    box-shadow: rgb(0, 0, 0, 0.7) 0.2em 0.2em 0.5em;
    -ms-touch-action: none;
    touch-action: none; 
}
  
#signature-pad {
    position: relative;
    width: 100%;
    height: 160px;
    -moz-user-select: none;
    -webkit-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

#signatureImg{
    width: 100%;
}

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
   
        <div id="content">
            <div class="wrap">
                   <hr style="border:15px;"><hr style="border:2px;">
                    
                    <div id="wrapper">
                        <div id="content">
                            <div id="pdf-container" >                   
                                <div id="signers-list">
                                   <div id="signer-1" class="signer-box"></div>
                                </div>                  
                                <img id="pdf-page" src="data:image/png;base64,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    </body>
</html>

Below is the back-end code to handle the stamping part using iText:

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
    File file = new File("D:\\Documents\\pruebaPdf\\Ejemplo_Uno.pdf");
            file.getParentFile().mkdirs();
            PdfReader reader = new PdfReader("D:\\Documents\\pruebaPdf\\Ejemplo_Uno.pdf");
     PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("D:\\Documents\\pruebaPdf\\Ejemplo_Dos.pdf"));
             Document document = new Document();
            
            try {
              
   PdfContentByte cb = stamper.getOverContent(request.getParameter("page"));
        
   float top = Float.valueOf(request.getParameter("top"));
  float left = Float.valueOf(request.getParameter("left"));
  float width = Float.valueOf(request.getParameter("width"));
  float height = Float.valueOf(request.getParameter("height"));
    
            // Just in case, take into account page rotation
            Rectangle pdfRectangle = reader.getPageSizeWithRotation(1);
    
            float pdfWidth = pdfRectangle.getWidth();
            float pdfHeight = pdfRectangle.getHeight();
    
            float llx = pdfWidth * left;
            float lly = pdfHeight * (1 - top - height);
            // Until iText 5 this code should work
            float urx = llx + (pdfWidth * width);
            float ury = lly + (pdfHeight * height);
            
           Rectangle rect = new Rectangle(llx, lly, urx, ury);
    
  rect.setBorder(Rectangle.BOX);
  rect.setBorderWidth(1);
  rect.setBackgroundColor(BaseColor.GRAY);
  rect.setBorderColor(BaseColor.GREEN);
  cb.rectangle(rect);
          
  } catch (Exception e) {
                System.out.println("ERROR=>>>>>>" + e);
   }finally{
     stamper.close();
     reader.close();
     document.close();
   }
    
 }

The position where I want the painting to come out

the position that I obtain with the coordinates that are calculated

You mention itext and imply that the pdf manipulated using itext has the stamp at the wrong position. So the code using itext is important here. — mkl, Jul 29 '21 at 20:46
As far as I can see the request parameters *mouseTop* and *mouseLeft* are never set. But they are used in the servlet to position the stamp. — mkl, Jul 29 '21 at 21:14
But even if you merely forgot to mention the code responsible for setting those parameters, just say one thing: You are aware that you work in different coordinate systems in the browser and in the pdf and transform the coordinates accordingly, don't you? — mkl, Jul 29 '21 at 21:26
@mkl and @K J It is exactly what I have in detail, I know it is not the same and that the coordinates will not coincide, so I asked for help to see if someone could help me — Sebastian Ruiz, Jul 30 '21 at 00:19
@LouisCloete concerning your edit commented as *"This has absolutely nothing to do with Java. Java !== Javascript and Java != Javascript is even false as well."* - The question is about a JavaScript front end interacting with a Java back end. Thus, both tags _do_ apply. — mkl, Aug 13 '21 at 08:38
Yes, I saw that later, but SO doesn't have the option to undo edit suggestions. I hoped the edit won't be accepted. If I could I'd just remove that edit altogether. Thanks for adding Java back as tag. — Louis Cloete, Aug 13 '21 at 08:42

jccampanero · Accepted Answer · 2021-08-07T21:39:48.440

As indicated in this companion question, the goal is to be able to translate the position and dimension of your image relative to the PDF between its representation in the browser and in the actual PDF.

In this specific use case you already have a well defined structure of elements, in which your PDF preview image is displayed in a predictable way.

Following the advice of the aforementioned question, I think you need to take the relevant points of your signature box, say:

var $signatureBox = $('.signer-box');
var sbDataX = parseFloat($signatureBox.attr('data-x'));
var sbDataY = parseFloat($signatureBox.attr('data-y'));
var sbOuterWidth = $signatureBox.outerWidth();
var sbOuterHeight = $signatureBox.outerHeight();

And convert them to percentages relative to the width and height of your PDF image:

var w = $('#pdf-page').width();
var h = $('#pdf-page').height();

var top = sbDataY / h;
var left = sbDataX / w;
var width = sbOuterWidth / w;
var height = sbOuterHeight / h;

I have used values relative to the unit, please, feel free to multiply them by 100 if you prefer to work with percentages. Just take into consideration in the next step.

These relative values top, left, width and height will be sent to your backend.

This information can be computed in your different listeners. Consider for example the definition of a common function that will be used to defined the right form values when either a drag and drop or a resize event occur:

window.dragMoveListener = dragMoveListener;

interact('.signer-box')
        .draggable({
            onmove: dragMoveListener,
            inertia: true,
            autoScroll: true,
            restrict: {
                elementRect: {top: 0, left: 0, bottom: 1, right: 1}
            }
        })
        .resizable({
            onmove: resizeMoveListener,
            inertia: true,
            edges: {left: true, right: true, bottom: true, top: true}
        })

function dragMoveListener(event) {
    var target = event.target;
    var x = (parseFloat(target.getAttribute('data-x')) || 0) + event.dx;
    var y = (parseFloat(target.getAttribute('data-y')) || 0) + event.dy;
    target.style.webkitTransform = target.style.transform = 'translate(' + x + 'px, ' + y + 'px)';
    target.setAttribute('data-x', x);
    target.setAttribute('data-y', y);
    
    computeSignerBoxPosition();
}

function resizeMoveListener(event) {
    var target = event.target;
    var x = (parseFloat(target.getAttribute('data-x')) || 0);
    var y = (parseFloat(target.getAttribute('data-y')) || 0);
    x += event.deltaRect.left;
    y += event.deltaRect.top;

    target.style.width = event.rect.width + 'px';
    target.style.height = event.rect.height + 'px';
    target.style.webkitTransform = target.style.transform = 'translate(' + x + 'px,' + y + 'px)';
    target.setAttribute('data-x', x);
    target.setAttribute('data-y', y);
    
    computeSignerBoxPosition();
}

function computeSignerBoxPosition() {
    var $signatureBox = $('.signer-box');
    var sbDataX = parseFloat($signatureBox.attr('data-x'));
    var sbDataY = parseFloat($signatureBox.attr('data-y'));
    var sbOuterWidth = $signatureBox.outerWidth();
    var sbOuterHeight = $signatureBox.outerHeight();

    var w = $('#pdf-page').width();
    var h = $('#pdf-page').height();
    
    var top = sbDataY / h;
    var left = sbDataX / w;
    var width = sbOuterWidth / w;
    var height = sbOuterHeight / h;

    document.getElementById("widthValue").value = width;
    document.getElementById("heightValue").value = height;
    document.getElementById("coorX").value = left;
    document.getElementById("coorY").value = top;
}

As mentioned, the idea is to compute the information that should be send to the backend when both listeners change. As an optimization, instead of computing the necessary information in the listener, please, consider attach to the button or visual element that you are using to submit your form a click listener that invoke the mentioned computeSignerBoxPosition function prior sending the information to the backend as it is only necessary in that moment.

With that information, as indicated in the original answer, you can obtain the right position like this:

float top = Float.valueOf(request.getParameter("top"));
float left = Float.valueOf(request.getParameter("left"));
float width = Float.valueOf(request.getParameter("width"));
float height = Float.valueOf(request.getParameter("height"));

// Just in case, take into account page rotation
Rectangle pdfRectangle = reader.getPageSizeWithRotation(1);

float pdfWidth = pdfRectangle.getWidth();
float pdfHeight = pdfRectangle.getHeight();

float llx = pdfWidth * left;
float lly = pdfHeight * (1 - top - height);
// Until iText 5 this code should work
float urx = llx + (pdfWidth * width);
float ury = lly + (pdfHeight * height);
// It seems that changed in Itext7 to this (they use just width and height)
// If it is your use case, please, comment the block above 
// and uncomment the following lines
// float urx = pdfWidth * width;
// float ury = pdfHeight * height;

Rectangle rect = new Rectangle(llx, lly, urx, ury);

PdfStampAnnotation stamp = new PdfStampAnnotation(rect).setStampName(new PdfName("Approved"));
PdfFormXObject xObj = new PdfFormXObject(new Rectangle(width,height));
PdfCanvas canvas = new PdfCanvas(xObj,doc);
canvas.addImage(image,0,0,false);

The algorithm takes into consideration that in PDF the lower-left corner of the page coincides with the origin of the coordinate system (0, 0), where positive x values are to the right of the origin and positive y values are above the origin (in contrast with the browser):

The credit for the image is for Bruno Lowagie when he describes how to interpret the coordinates of a rectangle in PDF and where is the origin of a PDF page.

It is important to note as well that the actual dimensions of your image and the PDF page in their representation in the browser and the actual PDF file should be constant, they need to preserve the proper aspect ratio; on the contrary, you need to correct your dimensions by the corresponding factor.

According to your new question, it I very important to note that the `Rectangle` definition changed in iText7. As explained in the answer, until [iText 5](https://api.itextpdf.com/iText5/java/5.5.10/com/itextpdf/text/Rectangle.html#Rectangle-float-float-float-float-) you need to pass the rectangle's lower left and upper right x and y coordinates, in that order. Since [iText7](https://api.itextpdf.com/iText7/java/7.1.0/com/itextpdf/kernel/geom/Rectangle.html#Rectangle-float-float-float-float-), they changed the meaning of the last two arguments to be the width and height of the rectangle. — jccampanero, Aug 05 '21 at 10:30
Depending on the version of the library you are using you need to take into consideration this fact. — jccampanero, Aug 05 '21 at 10:30
Hello @jccampanero if it helped me however for the positions of x and and they still do not come out correct, I have updated the question with the code that I mention — Sebastian Ruiz, Aug 06 '21 at 04:24
Hi @SebastianRuiz. Thank you very much for the feedback. Sorry, but I do not understand: you mean that the x and y position are still incorrect, is it right? Perhaps it has to do with the moment you are computing then in your code. Please, see the updated answer: the idea is to compute the information either in both listeners or ideally prior form submission. Please, can you try and see? Thank you. — jccampanero, Aug 06 '21 at 10:07
Hi @jccampanero I have updated the question to show what I get — Sebastian Ruiz, Aug 06 '21 at 15:21
Hi @SebastianRuiz. Of course... Sorry... All is fine, except that the definition of `top` and `left` are interchanged, they should be `var top = sbDataY / h; var left = sbDataX / w;`, as well as the values for `coorX` and `coorY`, thy should be `document.getElementById("coorX").value = left; document.getElementById("coorY").value = top;`. Please, see the updated answer. Please, can you try? — jccampanero, Aug 06 '21 at 17:50
I already worked, brother thank you very much, do you have any place where I can follow you? — Sebastian Ruiz, Aug 06 '21 at 21:58
You are welcome!! That is great @SebastianRuiz!! I am very very happy to hear that it worked properly. Thank you mate, although I don't think I deserve it... no Sebastian, unfortunately not: I will update my profile here if someday I wrote a blog or something similar. Thank you very much, I appreciate a lot that you want to follow me. Please, do not hesitate to contact me again if you need further help, I will be glad to help you if I can. — jccampanero, Aug 06 '21 at 22:15
@SebastianRuiz I do not wanna say that you must grant me the bounty, but if you wanna give me the bounty it should be explicitly awarded before its time run out because you started it after I posted the answer. I am sorry to bother you, but it is quite frustrating when the bounty is lost for both the OP and the people who answered the question. Thank you very much — jccampanero, Aug 12 '21 at 21:30
@jccampero Excuse me friend, this is the first time I do it, has it already worked? — Sebastian Ruiz, Aug 13 '21 at 01:15
Hi @SebastianRuiz. Please, there is no need to apologize, on the contrary, excuse me and thank you very much. Yes, it worked. Usually, if you start a bounty and approve an answer, that answer will be the awarded, ... unless it was posted before the bounty starts. In that case, it is necessary to explicitly award it to that answer. Thank you very much again Sebastian, and sorry for the inconveniences. See you my friend — jccampanero, Aug 13 '21 at 13:48

Java Stamp on certain location of pdf using iText

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