Security Annotations using Python
This article shows how to use security annotations in PDF documents with Aspose.PDF for Python via .NET.
The example script demonstrates three common redaction workflows:
- mark text fragments with redaction annotations
- permanently apply existing redaction annotations
- redact a detected image area on a page
Mark Text Redaction
This workflow searches for matching text in the document and places redaction annotations over each match. It does not remove the content yet; it only marks the text for later redaction.
Open the PDF and search for the target text
Create a TextFragmentAbsorber for the search term and enable regular text search options before scanning all pages.
document = ap.Document(infile)
text_fragment_absorber = ap.text.TextFragmentAbsorber(search_term)
text_search_options = ap.text.TextSearchOptions(True)
text_fragment_absorber.text_search_options = text_search_options
document.pages.accept(text_fragment_absorber)
Create redaction annotations for each match
For every matched text fragment, create a RedactionAnnotation using the fragment rectangle and configure its visual appearance.
for text_fragment in text_fragment_absorber.text_fragments:
page = text_fragment.page
annotation_rectangle = text_fragment.rectangle
redaction_annotation = ap.annotations.RedactionAnnotation(
page, annotation_rectangle
)
redaction_annotation.fill_color = ap.Color.gray
redaction_annotation.border_color = ap.Color.red
redaction_annotation.color = ap.Color.white
redaction_annotation.overlay_text = "REDACTED"
redaction_annotation.text_alignment = ap.HorizontalAlignment.CENTER
redaction_annotation.repeat = True
page.annotations.add(redaction_annotation, True)
Save the marked PDF
document.save(outfile)
Complete example
def mark_text_redaction(infile, outfile, search_term):
document = ap.Document(infile)
text_fragment_absorber = ap.text.TextFragmentAbsorber(search_term)
text_search_options = ap.text.TextSearchOptions(True)
text_fragment_absorber.text_search_options = text_search_options
document.pages.accept(text_fragment_absorber)
for text_fragment in text_fragment_absorber.text_fragments:
page = text_fragment.page
annotation_rectangle = text_fragment.rectangle
redaction_annotation = ap.annotations.RedactionAnnotation(
page, annotation_rectangle
)
redaction_annotation.fill_color = ap.Color.gray
redaction_annotation.border_color = ap.Color.red
redaction_annotation.color = ap.Color.white
redaction_annotation.overlay_text = "REDACTED"
redaction_annotation.text_alignment = ap.HorizontalAlignment.CENTER
redaction_annotation.repeat = True
page.annotations.add(redaction_annotation, True)
document.save(outfile)
Apply Redaction
After redaction annotations have been added, this workflow permanently applies them on the first page. Once applied, the original content is removed from the document output.
Load the PDF and collect redaction annotations
document = ap.Document(infile)
redaction_annotations = [
annotation
for annotation in document.pages[1].annotations
if annotation.annotation_type == ap.annotations.AnnotationType.REDACTION
]
Apply each redaction annotation
The sample checks that each annotation can be treated as a RedactionAnnotation before calling redact().
for redaction_annotation in redaction_annotations:
if is_assignable(redaction_annotation, ap.annotations.RedactionAnnotation):
cast(ap.annotations.RedactionAnnotation, redaction_annotation).redact()
Save the redacted PDF
document.save(outfile)
Complete example
def apply_redaction(infile, outfile):
document = ap.Document(infile)
redaction_annotations = [
annotation
for annotation in document.pages[1].annotations
if annotation.annotation_type == ap.annotations.AnnotationType.REDACTION
]
for redaction_annotation in redaction_annotations:
if is_assignable(redaction_annotation, ap.annotations.RedactionAnnotation):
cast(ap.annotations.RedactionAnnotation, redaction_annotation).redact()
document.save(outfile)
Redact Area
This example redacts a detected image area instead of text. It scans the page for image placements, selects one placement rectangle, and adds a redaction annotation over that area.
Open the PDF and detect image placements
Use ImagePlacementAbsorber to find image positions on the first page.
document = ap.Document(infile)
image_placement_absorber = ap.ImagePlacementAbsorber()
page = document.pages[1]
page.accept(image_placement_absorber)
Create a redaction annotation for the selected image area
The sample uses the third detected image placement and applies the same redaction styling used in the text-marking example.
target_rect = image_placement_absorber.image_placements[2].rectangle
redaction_annotation = ap.annotations.RedactionAnnotation(page, target_rect)
redaction_annotation.fill_color = ap.Color.gray
redaction_annotation.border_color = ap.Color.red
redaction_annotation.color = ap.Color.white
redaction_annotation.overlay_text = "REDACTED"
redaction_annotation.text_alignment = ap.HorizontalAlignment.CENTER
redaction_annotation.repeat = True
Add the annotation and save the PDF
page.annotations.add(redaction_annotation, True)
document.save(outfile)
Complete example
def redact_area(infile, outfile):
document = ap.Document(infile)
image_placement_absorber = ap.ImagePlacementAbsorber()
page = document.pages[1]
page.accept(image_placement_absorber)
target_rect = image_placement_absorber.image_placements[2].rectangle
redaction_annotation = ap.annotations.RedactionAnnotation(page, target_rect)
redaction_annotation.fill_color = ap.Color.gray
redaction_annotation.border_color = ap.Color.red
redaction_annotation.color = ap.Color.white
redaction_annotation.overlay_text = "REDACTED"
redaction_annotation.text_alignment = ap.HorizontalAlignment.CENTER
redaction_annotation.repeat = True
page.annotations.add(redaction_annotation, True)
document.save(outfile)