Add/Improve docstrings on backends

Author: bosd

camelot/backends/__init__.py

@@ -1 +1,3 @@
+"""pypdf_table_extraction offers multiple backends to convert the PDFs to images so it can be analyzed by opencv."""
+
 from .image_conversion import ImageConversionBackend

camelot/backends/ghostscript_backend.py

@@ -1,6 +1,26 @@
+"""Creates a ghostscript backend class to convert a pdf to a png file."""
+
+
 class GhostscriptBackend:
+    """Classmethod to create GhostscriptScriptBackend."""
 
     def convert(self, pdf_path, png_path, resolution=300):
+        """Convert a PDF to a PNG image using Ghostscript .
+
+        Parameters
+        ----------
+        pdf_path : str
+            [description]
+        png_path : str
+            [description]
+        resolution : int, optional
+            [description], by default 300
+
+        Raises
+        ------
+        OSError
+            [description]
+        """
         try:
             import ghostscript
         except RuntimeError:

camelot/backends/image_conversion.py

@@ -1,3 +1,5 @@
+"""Classes tand functions for the ImageConversionBackend backends."""
+
 from .ghostscript_backend import GhostscriptBackend
 from .poppler_backend import PopplerBackend
 
@@ -6,7 +8,23 @@
 
 
 class ImageConversionBackend:
+    """Classes the ImageConversionBackend backend."""
+
     def __init__(self, backend="poppler", use_fallback=True):
+        """Initialize the conversion backend .
+
+        Parameters
+        ----------
+        backend : str, optional
+            [description], by default "poppler"
+        use_fallback : bool, optional
+            [description], by default True
+
+        Raises
+        ------
+        ValueError
+            [description]
+        """
         if backend not in BACKENDS.keys():
             raise ValueError(f"Image conversion backend '{backend}' not supported")
 
@@ -15,6 +33,22 @@ def __init__(self, backend="poppler", use_fallback=True):
         self.fallbacks = list(filter(lambda x: x != backend, BACKENDS.keys()))
 
     def convert(self, pdf_path, png_path):
+        """Convert PDF to png_path.
+
+        Parameters
+        ----------
+        pdf_path : str
+            Path where to read the pdf file.
+        png_path : str
+            Path where to save png file.
+
+        Raises
+        ------
+        type
+            [description]
+        type
+            [description]
+        """
         try:
             converter = BACKENDS[self.backend]()
             converter.convert(pdf_path, png_path)

camelot/backends/poppler_backend.py

@@ -1,3 +1,13 @@
+"""Creates a poppler backend class to convert a pdf to a png file.
+
+Raises
+------
+OSError
+    [description]
+ValueError
+    [description]
+"""
+
 import os
 import shutil
 import subprocess
@@ -8,7 +18,25 @@
 
 
 class PopplerBackend:
+    """Classmethod to create a poplerBackendBackend class."""
+
     def convert(self, pdf_path, png_path):
+        """Convert PDF to png.
+
+        Parameters
+        ----------
+        pdf_path : str
+            Path where to read the pdf file.
+        png_path : str
+            Path where to save png file.
+
+        Raises
+        ------
+        OSError
+            [description]
+        ValueError
+            [description]
+        """
         pdftopng_executable = shutil.which("pdftopng", path=path)
         if pdftopng_executable is None:
             raise OSError(