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

__init__ constructor

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init

Initializes a new instance of PreviewOptions class.

def __init__(self, create_page_stream):
    ...
Parameter Type Description
create_page_stream CreatePageStream Callable that defines method to create output page preview stream.

Example 

import os
from groupdocs.annotation import Annotator
from groupdocs.annotation.options import PreviewOptions, PreviewFormats

def generate_document_preview():
    output_dir = "./preview"
    os.makedirs(output_dir, exist_ok=True)

    open_streams = {}

    def create_page_stream(page_number):
        stream = open(os.path.join(output_dir, f"page_{page_number}.png"), "wb")
        open_streams[page_number] = stream
        return stream

    def release_page_stream(page_number, page_stream):
        stream = open_streams.pop(page_number, None)
        if stream:
            stream.close()

    with Annotator("./sample.pdf") as annotator:
        preview_options = PreviewOptions(create_page_stream, release_page_stream)
        preview_options.preview_format = PreviewFormats.PNG
        preview_options.page_numbers = [1]
        annotator.document.generate_preview(preview_options)

    print(f"Generated page preview image(s) in {output_dir}.")

init

Initializes a new PreviewOptions instance.

def __init__(self, create_page_stream, release_page_stream):
    ...
Parameter Type Description
create_page_stream CreatePageStream Delegate which defines method to create output page preview stream.
release_page_stream ReleasePageStream Delegate which defines method to release output page preview stream.

Example 

import os
from groupdocs.annotation import Annotator
from groupdocs.annotation.options import PreviewOptions, PreviewFormats

def generate_document_preview():
    output_dir = "./preview"
    os.makedirs(output_dir, exist_ok=True)

    open_streams = {}

    def create_page_stream(page_number):
        stream = open(os.path.join(output_dir, f"page_{page_number}.png"), "wb")
        open_streams[page_number] = stream
        return stream

    def release_page_stream(page_number, page_stream):
        stream = open_streams.pop(page_number, None)
        if stream:
            stream.close()

    with Annotator("./sample.pdf") as annotator:
        preview_options = PreviewOptions(create_page_stream, release_page_stream)
        preview_options.preview_format = PreviewFormats.PNG
        preview_options.page_numbers = [1]
        annotator.document.generate_preview(preview_options)

    print(f"Generated page preview image(s) in {output_dir}.")

See Also

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