Uneven borders of ellipse annotation when I try to rotate the PDF - itext

Question

I am trying to draw ellipse on a rotated PDF but the border of the ellipse appears thick and thin in center
Sample Code:
PdfAnnotation annotation = PdfAnnotation.createSquareCircle(stamper.getWriter(), rect, null, false);
annotation.setFlags(PdfAnnotation.FLAGS_PRINT);
annotation.setColor(getColor(annot.getBorderColor()));
// annotation.setBorder(new PdfBorderArray(2, 2, 2));
// annotation.setColor(getColor(annot.getBorderColor()));
annotation.setBorderStyle(new PdfBorderDictionary(3.5f, PdfBorderDictionary.STYLE_SOLID));
PdfContentByte cb = stamper.getOverContent(page);
if ((int) (orientation % 360) == 90 || (int) (orientation % 360) == 270)
{
w = rect.getHeight();
h = rect.getWidth();
}
else
{
w = rect.getWidth();
h = rect.getHeight();
}
PdfAppearance app = cb.createAppearance(w + 3.5f, h + 3.5f);
app.setColorStroke(getColor(annot.getBorderColor()));
app.setLineWidth(3.5);
app.ellipse(rect.getLeft() + 1.5, rect.getBottom() + 1.5, rect.getRight() - 1.5, rect.getTop() - 1.5);
app.stroke();
annotation.setAppearance(PdfAnnotation.APPEARANCE_NORMAL, app);
stamper.addAnnotation(annotation, page);

Answer 1

As already assumed in a comment a feature of iText (for rotated pages it attempts to pretend to the user that he has an upright coordinate system, not a rotated one) gets into your way. This feature unfortunately does only affect the dimensions of the annotation itself, not of the appearances you create for it.
If a page has a 90° or 270° rotation, therefore, you have to use appearance dimensions whose width and height are switched compared to the annotation dimensions you used.
Furthermore, one also has to consider the switched dimensions when drawing the ellipse on the appearance template. The code in the question and in the example code shared via google drive forgot this.
Finally, one shall not override the switched dimensions of the appearance template using PdfAppearance.setBoundingBox. The code in the example code shared via google drive did this.
False Example
If I create an ellipse annotation with appearance on a rotated page like this:
Rectangle rect = new Rectangle(202 + 6f, 300, 200 + 100, 300 + 150);
PdfAnnotation annotation = PdfAnnotation.createSquareCircle(stamper.getWriter(), rect, null, false);
annotation.setFlags(PdfAnnotation.FLAGS_PRINT);
annotation.setColor(BaseColor.RED);
annotation.setBorderStyle(new PdfBorderDictionary(3.5f, PdfBorderDictionary.STYLE_SOLID));
PdfContentByte cb = stamper.getOverContent(1);
PdfAppearance app = cb.createAppearance(rect.getWidth(), rect.getHeight());
app.setColorStroke(BaseColor.RED);
app.setLineWidth(3.5);
app.ellipse( 1.5, 1.5, rect.getWidth() - 1.5, rect.getHeight() - 1.5);
app.stroke();
annotation.setAppearance(PdfAnnotation.APPEARANCE_NORMAL, app);
stamper.addAnnotation(annotation, 1);
(CreateEllipse test testCreateEllipseAppearanceOnRotated)
I indeed get a funny ellipse:
Correct Example
If I create an ellipse annotation with appearance on a rotated page with switched dimensions like this, though:
Rectangle rect = new Rectangle(202 + 6f, 300, 200 + 100, 300 + 150);
PdfAnnotation annotation = PdfAnnotation.createSquareCircle(stamper.getWriter(), rect, null, false);
annotation.setFlags(PdfAnnotation.FLAGS_PRINT);
annotation.setColor(BaseColor.RED);
annotation.setBorderStyle(new PdfBorderDictionary(3.5f, PdfBorderDictionary.STYLE_SOLID));
PdfContentByte cb = stamper.getOverContent(1);
// switched appearance dimensions
PdfAppearance app = cb.createAppearance(rect.getHeight(), rect.getWidth());
app.setColorStroke(BaseColor.RED);
app.setLineWidth(3.5);
// draw ellipse using switched appearance dimensions
app.ellipse( 1.5, 1.5, rect.getHeight() - 1.5, rect.getWidth() - 1.5);
app.stroke();
annotation.setAppearance(PdfAnnotation.APPEARANCE_NORMAL, app);
stamper.addAnnotation(annotation, 1);
(CreateEllipse test testCreateCorrectEllipseAppearanceOnRotated)
I get the expected ellipse: