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https://github.com/lehoangan2906/djvu-to-pdf-converter
djvu to pdf converter
https://github.com/lehoangan2906/djvu-to-pdf-converter
Last synced: 8 days ago
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djvu to pdf converter
- Host: GitHub
- URL: https://github.com/lehoangan2906/djvu-to-pdf-converter
- Owner: lehoangan2906
- Created: 2024-02-05T14:55:13.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2024-11-27T05:05:40.000Z (2 months ago)
- Last Synced: 2024-11-27T06:20:59.194Z (2 months ago)
- Language: Python
- Size: 25.5 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# DJVU to PDF Converter
# Important Packages
- `DjVuLibre` : You can download it from this website: [http://djvu.sourceforge.net/](http://djvu.sourceforge.net/)
- `ImageMagick` : You can download it from this website: [https://imagemagick.org/script/download.php](https://imagemagick.org/script/download.php)
# Outline:
1. **Import Libraries**:
- Import the neccessary libraries (`os` for file-related ooperations and `subprocess` for running external commands.)
2. **Define Funtion ‘Converter’**
- Takes two parameters: `input_djvu` and `output_djvu` .
- Checks if the input DJVU file exists.
- Converts DJVU to PNM using `ddjvu` command line tool.
- Checks if the PNM file was created successfully.
- Converts PNM to PDF using `convert` command line tool.
- Checks if the PDF file was created successfully.
- Cleans up the intermediate PNM file.
- Prints a success message.
3. **Handle Exceptions:**
- Uses a `try-except` block to catch nay exceptions during the process.
- Prints an error message if an exception occurs.
# Step by Step explaination:
```python
# Import necessary libraries
import os
import subprocess
```
These lines import the required Python libraries.
- `os` provides a way to interact with the operating system (checking file existence, removing files)
- `subprocess` is used to run external commands from within Python.
```python
def converter(input_djvu, output_pdf):
try:
# Check if input DJVU file exists
if not os.path.exists(input_djvu):
raise FileNotFoundError(f"The file {input_djvu} does not exists.")
```
This function `converter` takes two parameters:
- `input_djvu` : the input djvu file
- `output_pdf` : the desire output PDF file
It starts with a check to see if the input DJVU file exists in the current folder. If not, it raises a `FileNotFoundError` with an appropriate message.
```python
# Use DjVuLibre's `ddjvu` command line tool to convert DJVU to PNM format
pnm_filename = output_pdf.replace(".pdf", ".pnm")
subprocess.run(["ddjvu", "-format=pnm", input_djvu, pnm_filename])
```
This part of the code calls the `ddjvu` command line tool with subprocess to convert the input DJVU file into PNM (Portable Anymap) format. It creates a temporary PNM file with a similar name to the output PDF.
- Why to we need to convert DJVU to PNM first?
The conversion from DJVU to PNM (Portable Anymap) is an intermediate step in the process because the **`convert`** command from ImageMagick, used for the final conversion to PDF, doesn't directly support DJVU input.
1. **DJVU to PNM:**
- **`ddjvu`** is a command-line tool from DjVuLibre that converts DJVU files to PNM format.
- PNM is a simple and versatile image format that stands for Portable Anymap. It's a common intermediate format used for various image processing tasks.
2. **PNM to PDF:**
- The **`convert`** command from ImageMagick is then used to convert the PNM file to PDF.
- ImageMagick supports a wide range of image formats, including PNM, and can easily convert them to PDF.
```python
# Check if PNM file was created successfully
if not os.path.exists(pnm_filename):
raise Exception("Conversion to PNM failed.")
```
After the conversion, it checks if the PNM file was created successfully. If not, it raises an exception indicating that the conversion failed.
```python
# Use ImageMagick's `convert` command line tool to convert PNM to PDF
subprocess.run(["convert", pnm_filename, output_pdf])
```
This part of the code uses the `convert` command line tool from ImageMagick to convert the PNM file into the final PDF format.
```python
# Check if PDF file was created successfully
if not os.path.exists(output_pdf):
raise Exception("Conversion to PDF failed.")
```
It then checks if the PDF file was created successfully. If not, it raises an exception idicating that the conversion to PDF failed.
```python
# Clean up intermediate PNM file
os.remove(pnm_filename)
```
After the successfull conversion, it removes the temporary PNM file to clean up.
```python
print(f"Conversion successful. PDF saved as {output_pdf}")
```
Finally, if everything is successful, it prints a message indicating the conversion was successful and the location of the saved PDF file.
```python
except Exception as e:
print(f"Error: {e}")
```
The `try-except` block catches any exceptions that might occur during the process and prints an error message if there’s an issue.
# To run this project
- First, copy and paste the djvu file you want to convert inside this code folder.
- Open the `main.py` file using any code editor or IDE (VSCode, Sublimetext, etc,.) and modify the value of `input_djvu_file` variable to your djvu file name, as well as the value of `output_pdf_file` variable to your desire output file name.
- Open terminal (or CMD if you're using Windows), navigate to this code folder, then enter the following prompt:
```bash
python3 main.py
```
And your converted file is now ready in the folder.