[Question] How to keep highlight when converting pdf to image

[CarolinaRDC]

Configuration

3.7.6 (tags/v3.7.6:43364a7ae0, Dec 19 2019, 00:42:30) [MSC v.1916 64 bit (AMD64)] 
 win32 
 
PyMuPDF 1.19.1: Python bindings for the MuPDF 1.19.0 library.
Version date: 2021-10-23 00:00:10.
Built for Python 3.7 on win32 (64-bit).

Hello, I've realised that once I've done the highlight annotation in the pdf I cannot keep it if I want to save it as an image. It automatically disappears. Is there a way of doing so?

The code:

def pdf_to_image(pdf_filename, x, highlight_text=None):

    if highlight_text is not None:
        highlight_within_pdf(pdf_filename, x, text_to_highlight=highlight_text, color=color['amarillo'])

        new_doc = fitz.open(REL["crops"] + '/' + 'new_crop_highlighted_{}.pdf'.format(x))
        new_page = new_doc.load_page(0)
        pix = new_page.get_pixmap(matrix=fitz.Matrix(150 / 72, 150 / 72), alpha=False)
        pix.save(REL["crops"] + '/' + 'cropped_page_{}.jpg'.format(x))
        new_doc.close()

def highlight_within_pdf(pdf_filename, x, text_to_highlight, color=None):
    doc = fitz.open(pdf_filename)
    page = doc.load_page(0)
    text_instances = page.search_for(text_to_highlight)

    highlight = page.add_highlight_annot(text_instances)
    highlight.set_colors({"stroke": color})
    highlight.update()
    doc.reload_page(page)

    doc.save(REL["crops"] + '/' + 'new_crop_highlighted_{}.pdf'.format(x), garbage=4, deflate=True, clean=True)
    doc.close()

There is no error. It just doesn't keep the highlighted sentence.
Thank you very much in advance

[JorjMcKie]

Page pixmap creation by default is with annotations included. So you should see them.
The only possible hickup is that right after an annot.update() MuPDF won't always have become aware of the changes PyMuPDF has inserted in the annotation.
So it is best to reload the page before taking the pixmap: page = doc.reload_page(page).
But after going to a different page, or after opening the PDF after such changes will do the same job.
If you save the document, all outstanding changes should be saved as well.

BTW: If you save a pixmap, you cannot directly use JPEG as output format: MuPDF doen't support this. But you could use pil_save() instead.

But the following does work as desired:

>>> doc=fitz.open("search.pdf")
>>> page=doc[0]
>>> annot = page.add_highlight_annot(page.search_for("beteigeuze"))
>>> annot.set_colors(stroke=(0,1,0))
>>> annot.update()
>>> pix =page.get_pixmap()
>>> pix.save("beteigeuze.png")
>>> doc.save("beteigeuze.pdf")
>>> 

Pixmap:

The PDF looks the same.

[CarolinaRDC]

Exactly! I tried with PNG and it worked perfectly.
I'm trying now with pil_save() because it is more suitable for our project to save it with JPEG output format.

Thank you very much for answering so so fast and for all the information given.

[JorjMcKie]

you are welcome 😎