Default settings for Export to PDF change the borders and image size of the resulting PDF

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Describe the bug
The default settings for exporting to PDF change the document borders and shrink the PDF image in the resulting PDF.

I need precise borders in documents that I produce. Previously, exporting to PDF using the default settings retained the precise borders that I established in the documents. Now, exporting to PDF using the default settings adds extra borders around the document, changing the borders that I've established for the document.

I noticed this behavior today and it goes back at least a couple of months. Documents I produced from one year ago do not have this problem.

I can fix the problem by setting "Border Width: 0" in the PDF export pop-up window. So, it appears that the default border width for PDF exports and printing has changed from 0 to 27 pixels in a recent version. As far as I can tell, this change was not documented in the changelogs.

To Reproduce
Steps to reproduce the behavior:

1. Export a document using the default Export to PDF settings.

Steps to correct behavior to previous behavior:

1. Manually change the Border Width: to 0 when exporting a document using the Export to PDF settings.

Expected behavior

1. The default Export to PDF settings should NOT change the borders of the resulting PDF.
2. There should also be a way to set the default Border Width for all documents.

Screenshots

251124-Margin Example-Default Border=27.pdf

251124-Margin Example-Border=0.pdf

draw.io version (In the Help->About menu of the draw.io editor):

• draw.io version 29.0.3

Desktop (please complete the following information):

• OS: MacOS Sequoia 15.6.1

Start by reproducing the issue in draw.io version 29.0.3 on macOS using the default Export to PDF settings, then repeat with Border Width set to 0. Compare the resulting borders and image size; done means the default export preserves document borders and the expected image dimensions, with the requested default-setting behavior addressed.