DOC: Watermark and stamp

docs/user/add-watermark.md

@@ -10,57 +10,76 @@ content stays the same.
 ## Stamp (Overlay)
 
 ```python
-from PyPDF2 import PdfWriter, PdfReader
-
-
-def stamp(content_page, image_page):
- """Put the image over the content"""
- # Note that this modifies the content_page in-place!
- content_page.merge_page(image_page)
- return content_page
-
+from pathlib import Path
+from typing import Union, Literal, List
 
-# Read the pages
-reader_content = PdfReader("content.pdf")
-reader_image = PdfReader("image.pdf")
+from PyPDF2 import PdfWriter, PdfReader
 
-# Modify it
-modified = stamp(reader_content.pages[0], reader_image.pages[0])
 
-# Create the new document
-writer = PdfWriter()
-writer.add_page(modified)
-with open("out-stamp.pdf", "wb") as fp:
- writer.write(fp)
+def stamp(
+ content_pdf: Path,
+ stamp_pdf: Path,
+ pdf_result: Path,
+ page_indices: Union[Literal["ALL"], List[int]] = "ALL",
+):
+ reader = PdfReader(stamp_pdf)
+ image_page = reader.pages[0]
+
+ writer = PdfWriter()
+
+ reader = PdfReader(content_pdf)
+ if page_indices == "ALL":
+ page_indices = list(range(0, len(reader.pages)))
+ for index in page_indices:
+ content_page = reader.pages[index]
+ mediabox = content_page.mediabox
+ content_page.merge_page(image_page)
+ content_page.mediabox = mediabox
+ writer.add_page(content_page)
+
+ with open(pdf_result, "wb") as fp:
+ writer.write(fp)
 ```
 
 ![stamp.png](stamp.png)
 
 ## Watermark (Underlay)
 
 ```python
+from pathlib import Path
+from typing import Union, Literal, List
+
 from PyPDF2 import PdfWriter, PdfReader
 
 
-def watermark(content_page, image_page):
- """Put the image under the content"""
- # Note that this modifies the image_page in-place!
- image_page.merge_page(content_page)
- return image_page
+def watermark(
+ content_pdf: Path,
+ stamp_pdf: Path,
+ pdf_result: Path,
+ page_indices: Union[Literal["ALL"], List[int]] = "ALL",
+):
+ reader = PdfReader(content_pdf)
+ if page_indices == "ALL":
+ page_indices = list(range(0, len(reader.pages)))
+
+ reader_stamp = PdfReader(stamp_pdf)
+ image_page = reader_stamp.pages[0]
 
+ writer = PdfWriter()
+ for index in page_indices:
+ content_page = reader.pages[index]
+ mediabox = content_page.mediabox
 
-# Read the pages
-reader_content = PdfReader("content.pdf")
-reader_image = PdfReader("image.pdf")
+ # You need to load it again, as the last time it was overwritten
+ reader_stamp = PdfReader(stamp_pdf)
+ image_page = reader_stamp.pages[0]
 
-# Modify it
-modified = stamp(reader_content.pages[0], reader_image.pages[0])
+ image_page.merge_page(content_page)
+ image_page.mediabox = mediabox
+ writer.add_page(image_page)
 
-# Create the new document
-writer = PdfWriter()
-writer.add_page(modified)
-with open("out-watermark.pdf", "wb") as fp:
- writer.write(fp)
+ with open(pdf_result, "wb") as fp:
+ writer.write(fp)
 ```
 
 ![watermark.png](watermark.png)