How to Permanently Modify Layer Visibility in PDFs

[StefanIonutTasca]

In the example below, I am trying to manipulate the visibility of a specific layer in a PDF file. I use the screenshot_page function to generate screenshots of the page with the layer visibility adjusted, and these screenshots reflect the changes correctly. However, when I use the save_pdf_with_layer function to save a new PDF with the adjusted layer visibility, the saved PDF does not reflect these changes.

Expected Behavior
The saved PDFs should reflect the changes made to layer visibility, showing or hiding specific layers as adjusted in the code.

Actual Behavior
The screenshots generated reflect the changes to layer visibility correctly. However, the PDFs saved using the save_pdf_with_layer function do not reflect these changes; the layers do not appear as expected based on the visibility settings.

import fitz

def list_all_ocg_ids(pdf_path):
"""
List all the OCG IDs (Optional Content Group IDs) in the given PDF.

Args:
- pdf_path (str): Path to the PDF file.

Returns:
- List[str]: List of OCG IDs.
"""
# Open the PDF
doc = fitz.open(pdf_path)

# Fetch the OCGs
ocgs = doc.get_ocgs()

# Extract and return the OCG IDs
ocg_ids = list(ocgs.keys())

# Close the document
doc.close()

return ocg_ids

def save_pdf_with_layer(pdf, output_pdf_path, ocg_id, action):
"""Save a copy of the PDF with a specific OCG state."""

# Adjust the visibility of the OCG based on the action
ocgs = pdf.get_ocgs()
for id, ocg in ocgs.items():
    if id == ocg_id:
        visibility = True if action == 2 else False
        for page in pdf:
            page.set_layer_visibility(ocg, visibility)

pdf.save(output_pdf_path)
print(f"Saved PDF to {output_pdf_path} with OCG ID {ocg_id} set to {'ON' if action == 2 else 'OFF'}")

def screenshot_page(pdf, output_image_path, ocg_id, action, page_number=0):
"""Generate a screenshot of the specified page with a specific OCG state."""
page = pdf.load_page(page_number)

# Adjust the visibility of the OCG based on the action
ocgs = pdf.get_ocgs()
for id, ocg in ocgs.items():
    if id == ocg_id:
        visibility = True if action == 2 else False
        page.set_layer_visibility(ocg, visibility)

pix = page.get_pixmap()
pix.save(output_image_path)
print(f"Saved screenshot to {output_image_path}")

list_all_ocg_ids("TEST.pdf")
doc = fitz.open("TEST.pdf")
for item in doc.layer_ui_configs():
print(item)
print()

Set OCG with ID 2 to ON

doc.set_layer_ui_config(1, action=2)

Take a screenshot of the first page reflecting the change

screenshot_page(doc, "screenshot.png", 1, 0)
save_pdf_with_layer(doc, "output_ON.pdf", 2, 2)

Set OCG with ID 2 to OFF

doc.set_layer_ui_config(1, action=0)

Take another screenshot of the first page reflecting the change

screenshot_page(doc, "screenshot2.png", 1, 0)
save_pdf_with_layer(doc, "output_OFF.pdf", 2, 0)

doc.close()

[JorjMcKie]

fitz.Page has no method set_layer_visibility(). Where does this come from?
Don't say it was ChatGPT ... 😉.

If you use _ui_ method(s) to modify the layer, then this is temporary only. That setting will not become part of the PDF file.
For permanent changes use doc.set_layer().

[StefanIonutTasca]

I tried to use this:https://github.com/pymupdf/PyMuPDF-Utilities/blob/master/jupyter-notebooks/optional-content.ipynb,

In the tutorial I found:
doc.set_layer_ui_config(number, action): Use this to change the state of one of the OCGs, numbered as shown. This method does the same thing as offered by supporting PDF viewers.
action is an integer with the following meanings: 0 = set on (default), 1 = toggle on/off, 2 = set off.

I would like to stick to UI because my end-goal is to create an automation based on it.

[JorjMcKie]

If you don't permanantly set the OCG as described, the current situation will not arrive in the file.
Pleas consult the documentation here.