Java iText Rotate a Link Rectangle

Question

I need to rotate a link rectangle using Java iText.

The original link rectangle appears in red. The rotated link rectangle appears in green.

My code:

PdfReader reader = new PdfReader( "input/blank.pdf" );
PdfStamper stamper = new PdfStamper( reader, new FileOutputStream(  "output/blank_stamped.pdf" ) );
Rectangle linkLocation = new Rectangle( 100, 700, 100 + 200, 700 + 25 );
PdfName highlight = PdfAnnotation.HIGHLIGHT_INVERT;
PdfAnnotation linkRed  = PdfAnnotation.createLink( stamper.getWriter(), linkLocation, highlight, "red" );
PdfAnnotation linkGreen = PdfAnnotation.createLink( stamper.getWriter(), linkLocation, highlight, "green" );
BaseColor baseColorRed = new BaseColor(255,0,0);
BaseColor baseColorGreen = new BaseColor(0,255,0);
linkRed.setColor(baseColorRed);
linkGreen.setColor(baseColorGreen);
double angleDegrees = 10;
double angleRadians = Math.PI*angleDegrees/180;
stamper.addAnnotation(linkRed, 1);
linkGreen.applyCTM(AffineTransform.getRotateInstance(angleRadians));
stamper.addAnnotation(linkGreen, 1);
stamper.close();

But this code does not rotate the recangle.

Answer 1

Please take a look at the following screen shot:

I have added 5 annotations to a simple Hello World file.

The first two are link annotations. Their position is defined by the rectangles linkLocation1 and linkLocation2 :

Rectangle linkLocation1 = new Rectangle(30, 770, 120, 800);
PdfAnnotation link1 = PdfAnnotation.createLink(stamper.getWriter(),
        linkLocation1, PdfAnnotation.HIGHLIGHT_INVERT, action);
link1.setColor(BaseColor.RED);
stamper.addAnnotation(link1, 1);
Rectangle linkLocation2 = new Rectangle(30, 670, 60, 760);
PdfAnnotation link2 = PdfAnnotation.createLink(stamper.getWriter(),
        linkLocation2, PdfAnnotation.HIGHLIGHT_INVERT, action);
 link2.setColor(BaseColor.GREEN);
 stamper.addAnnotation(link2, 1);

The green rectangle looks like a rotated version of the red rectangle, but that's not really true: we just defined the "clickable" area that way. I don't understand why you'd want to get this effect by introducing a rotation. Why? Because a rotation always needs a rotating point. Suppose that you would introduce a rotation, what would be your rotation point? The (0, 0) coordinate? That would lead to strange results, wouldn't it?

Introducing a rotation for does make sense for some types of annotations though. In my example, I introduced three stamp annotations:

Rectangle linkLocation3 = new Rectangle(150, 770, 240, 800);
PdfAnnotation stamp1 = PdfAnnotation.createStamp(stamper.getWriter(), linkLocation3, "Landscape", "Confidential");
stamper.addAnnotation(stamp1, 1);
Rectangle linkLocation4 = new Rectangle(150, 670, 240, 760);
PdfAnnotation stamp2 = PdfAnnotation.createStamp(stamper.getWriter(), linkLocation4, "Portrait", "Confidential");
stamp2.setRotate(90);
stamper.addAnnotation(stamp2, 1);
Rectangle linkLocation5 = new Rectangle(250, 670, 340, 760);
PdfAnnotation stamp3 = PdfAnnotation.createStamp(stamper.getWriter(), linkLocation5, "Portrait", "Confidential");
stamp3.setRotate(45);
stamper.addAnnotation(stamp3, 1);

In this case, I introduce a rotation angle using the setRotate() method. This rotates the CONFIDENTIAL stamp inside the rectangle we defined. As you can see, this makes sense because the annotation does have actual content: the rotation has an impact on the way you read the word CONFIDENTIAL . In the case of the clickable area of the link annotation, there is no such content to be rotated.

If this doesn't answer your question, please rephrase your question because I don't think anyone can answer it in its current state.

Update Please take a look at ISO-32000-1 aka the PDF specification. You'll discover that a rectangle is defined using 4 values: the x and y coordinate of the lower-left corner of the rectangle and the x and y coordinate of the upper-right corner of the rectangle. These are the two starting points of the horizontal and vertical sides. You want a rectangle that has sides that aren't horizontal/vertical. Obviously that isn't possible as you'd need the coordinates of 4 corner points to achieve that (8 values, not 4). You can achieve this using a polygon defined by QuadPoints. See ITextShape Clickable Polygon or path