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Change contrast of pdf using python
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| """ | |
| # pdf_contrast.py | |
| Modify contrast of pdf | |
| ## Install | |
| ``` | |
| pip install Pillow pdf2image img2pdf tqdm | |
| ``` | |
| > Save this file as pdf_contrast.py | |
| ## USAGE | |
| ``` | |
| $ python pdf_contrast.py 2.3 -i in.pdf -o out.pdf | |
| Loading pdf in.pdf | |
| Pages: 48 | |
| Contrast x2.3: 100%|███████████████████████| 48/48 [00:02<00:00, 18.42pages/s] | |
| Saving pdf to out.pdf | |
| ``` | |
| """ | |
| from argparse import ArgumentParser | |
| import io | |
| from PIL import ImageEnhance | |
| import img2pdf | |
| import pdf2image | |
| from tqdm import tqdm | |
| def pdf_contrast(input_file: str, contrast: float, output_file: str): | |
| """ | |
| Create a new pdf corresponding to the contrast multiplier | |
| `input_file`: name the of the input_file | |
| `contrast`: contrast multiplier. 1 corresponds to no change | |
| `output_file`: name of the file to be saved | |
| """ | |
| print(f'Loading pdf {input_file}') | |
| input_images = pdf2image.convert_from_path(input_file) | |
| print(f'Pages: {len(input_images)}') | |
| output_images: list[bytes] = [] | |
| for img in tqdm(input_images, | |
| desc=f"Contrast x{contrast}", | |
| unit="pages" | |
| ): | |
| enhancer = ImageEnhance.Contrast(img) | |
| out_im = enhancer.enhance(contrast) | |
| out_img_bytes = io.BytesIO() | |
| out_im.save(out_img_bytes, format="JPEG") | |
| output_images.append(out_img_bytes.getvalue()) | |
| print(f'Saving pdf to {output_file}') | |
| with open(output_file, "wb") as outf: | |
| img2pdf.convert(*output_images, outputstream=outf) | |
| if __name__ == "__main__": | |
| input_file = "in.pdf" | |
| contrast = 1.2 | |
| output_file = f"out_contrast{contrast}.pdf" | |
| parser = ArgumentParser(description="Modify contrast of pdfs") | |
| parser.add_argument('-i', '--input', | |
| help="Input filename", | |
| dest="input_file") | |
| parser.add_argument('-o', '--output', | |
| help="Output file name", | |
| dest="output_file") | |
| parser.add_argument('contrast', type=float, | |
| help=""" | |
| Contrast multipler, must be a float. | |
| 1 corresponds to no change (1x). | |
| 2 corresponds to double (2x). | |
| 0.5 corresponds to half (0.5x). | |
| """) | |
| args = parser.parse_args() | |
| pdf_contrast(args.input_file, args.contrast, args.output_file) |
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