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Extract Highlights from PDF in A Quick and Safe Manner

author
Published By Nilesh Kumar
Debasish Pramanik
Approved By Debasish Pramanik
Published On September 11th, 2023
Reading Time 6 Minutes Reading
Category PDF Tips

In today’s fast-paced digital world, information reigns supreme, and PDFs have emerged as a popular format for presenting that knowledge. Moreover, you must have come across PDF files that were full of helpful information as a student, researcher, or professional. However, the issue that all users have is: Can we extract highlights from PDF, and if so, how? Don’t worry; reading this blog already puts you halfway there as we offer a step-by-step overview of both the basic method as well as an automated utility. Let us first define highlights in a PDF document.

What is Highlighted Text in the Context of PDF?

PDF highlighting, at its core, is the skill of emphasizing certain text inside a PDF document. In other words, transforms plain text into a visual roadmap for the reader. Moreover, highlights act as markers that draw attention to critical information, which in turn makes it easier to reference and interpret the content of the text.

Also Read: Learn How to Change PDF Permissions and Modify PDF Settings

Many users think that PDF highlights are nothing more than simple underlining or coloring text. This is a major reason that they are not able to extract highlighted text from PDF documents. Therefore it is vital to understand that highlighting also includes comments and annotations as well.  Which can be used to contribute their views, write down explanations, or scribble ideas directly into the page itself. So now that we have a fair idea of what highlights are, let’s see some scenarios where users may fail to extract highlights from PDF.

Situations Where Highlight Extraction from PDF is Difficult

  • Security Restrictions: Password protection or encryption can hinder highlight extraction.
  • Scanned Documents: If a PDF is scanned & lacks OCR-recognized text, highlights won’t work.
  • Corrupted Files: Corrupted PDFs may disrupt or prevent the extraction process.
  • Unsupported Software: Not all PDF software supports highlight extraction.
  • Incompatibility: Some PDFs may not work with certain extraction tools or software.
  • Large Files: Very large PDFs might cause performance issues during extraction.
  • Document Permissions: Permissions can restrict highlighting, even in unprotected PDFs.
  • Complex Layouts: Complex layouts can make extraction challenging.
  • Inaccessible Annotations: Annotations may be impossible to retrieve.
  • Highlight Limitations: Highlight extraction options vary by software.

Don’t worry as we have an expert-recommended solution which can bypass all these issues.

Professional Method to Extract Highlights from PDF

In the entire market of such tools, none can match the ease of use of the Automated PDF Extraction tool. Additionally, the reason for its popularity is the list of features like.

  • Extraction of data from multiple PDF files at once.
  • Maintain the text format and only get what you asked for.
  • Gives the option to extract data into separate folders.
  • Users can apply specific settings to individual pages.
  • Available for both Windows and Mac users.
  • Freedom to export highlighted text from PDF to Word format.
  • No hidden subscription fees or technical knowledge is required to operate the tool.

You can get the trial version and find out how this well-made tool helps you in various tasks relating to a PDF file.

Apart from this, there are a lot more features present within a single package for professionals in every field. Now let’s look at the steps to use this advanced utility.

Steps for Highlight Extraction Via the Tool

Step 1. Install and Launch the software on your PC.

Launch the Tool

Step 2. Within the interface find and click on the Add Files / Add Folder button.

Add PDF Files

Step 3. Press the Change to choose a location to save the resultant data then press Next.

change

Step 4. Go to the Comments section and mark the box next to Save the Highlighted Text Into.

Choose Output Format

Step 5. Apply Page Settings to make an accurate page selection.

Apply Page Settings

Step 6. Then, click on the “Extract” button which starts the extraction from PDF file.

Press Extract

Manual Methods of Highlight Extraction from PDF 

Using Copy Paste: 

Well if you have a lot of free time and basically zero-budget copy-pasting is a way with which you can get the highlighted text from a PDF. Follow the steps and find out for yourself.

Step 1. Open the PDF document in your preferred viewer.

Step 2. Select the highlighted text and hit Ctrl + C (or Command + C for Mac users).

Step 3. In another document editor like Word, Notepad, etc. Place your cursor and press Ctrl + V (or Command + V for Mac users).

Limitations:

  • It can only extract from PDF files which have no passwords or permissions blocking copy-pasting of data.
  • Each part of the highlighted text has to be copied and pasted manually so it’s not feasible for large documents.

Using Python Library

# Import libraries

import PyMuPDF

import fitz


# Open the PDF

pdf_document = fitz.open("sample.pdf")


# Access the first page

pdf_page = pdf_document[0]


# Store the coordinates of all highlights

highlight_coordinates = []


# Loop through annotations

annotation = pdf_page.firstAnnot

while annotation:

    if annotation.type[0] == 8:  # Check if it's a highlight annotation

        all_coords = annotation.vertices

        if len(all_coords) == 4:

            highlight_rect = fitz.Quad(all_coords).rect

            highlight_coordinates.append(highlight_rect)

        else:

            all_coords = [all_coords[x:x+4] for x in range(0, len(all_coords), 4)]

            for i in range(0, len(all_coords)):

                coord = fitz.Quad(all_coords[i]).rect

                highlight_coordinates.append(coord)

    annotation = annotation.next


# Extract all words and their coordinates

word_coordinates = pdf_page.getTextWords()


# Store highlighted texts

highlighted_text = []


# Loop through highlight coordinates and check for intersection with words

for h in highlight_coordinates:

    sentence = [word[4] for word in word_coordinates if fitz.Rect(word[0:4]).intersect(h)]

    highlighted_text.append(" ".join(sentence))


# Print the extracted highlighted text

print(" ".join(highlighted_text))

Limitations:

  • Highly technical and requires deep knowledge of Python language.
  • Can result in permanent data loss or corrupt the PDF itself.

Conclusion

Finally, we hope that the advice in this post enabled readers to extract highlights from PDF files. Furthermore, we propose that they use the previously stated automatic tool, which can quickly extract all highlighted text from PDF documents. This saves time and boosts efficiency at work or school.