1. API Reference
  2. /
  3. GroupDocs.Watermark
  4. /
  5. GroupDocs.Watermark for Python via .NET
  6. /
  7. groupdocs.watermark.options
  8. /
  9. PreviewOptions class
  10. /
  11. __init__ constructor

__init__ constructor

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init

Initializes a new PreviewOptions instance that closes the output stream after use.

def __init__(self, create_page_stream):
    ...
Parameter Type Description
create_page_stream CreatePageStream Callable[[int], io.RawIOBase] – Creates a stream for a specific page preview.

Example 

from groupdocs.watermark import Watermarker
from groupdocs.watermark.options import PreviewOptions, PreviewFormats

def generate_preview():
    # Supply a writable file stream for each page to render
    def create_page_stream(page_number):
        return open(f"./output-page-{page_number}.png", "wb")

    with Watermarker("./sample.pdf") as watermarker:
        options = PreviewOptions(create_page_stream)
        options.preview_format = PreviewFormats.PNG
        options.page_numbers = [1, 2]
        watermarker.generate_preview(options)

if __name__ == "__main__":
    generate_preview()

init

Initializes a new PreviewOptions instance that returns the output stream to the client for further use.

def __init__(self, create_page_stream, release_page_stream):
    ...
Parameter Type Description
create_page_stream CreatePageStream Callable that creates a stream for a specific page preview. Receives the page number (int) and should return a writable stream (io.RawIOBase).
release_page_stream ReleasePageStream Callable that is invoked when page preview generation is complete and provides the output stream.

Example 

from groupdocs.watermark import Watermarker
from groupdocs.watermark.options import PreviewOptions, PreviewFormats

def generate_preview():
    # Supply a writable file stream for each page to render
    def create_page_stream(page_number):
        return open(f"./output-page-{page_number}.png", "wb")

    with Watermarker("./sample.pdf") as watermarker:
        options = PreviewOptions(create_page_stream)
        options.preview_format = PreviewFormats.PNG
        options.page_numbers = [1, 2]
        watermarker.generate_preview(options)

if __name__ == "__main__":
    generate_preview()

See Also

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