Discover how to manipulate PDFs using Python. Gain hands-on experience with real-life scenarios and broaden your knowledge in handling and processing PDF files efficiently.

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mypdftoolbox.tar.gz

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pdf_merger

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pdf_pages_remover

pdf_pages_shuffler

pdf_pages_watermarker

pdf_convert2img

pdf_extract_tables

pdf_extract_images

pdf_extract_links

pdf_annotator

pdf_redactor

pdf_parser

pdf_convert2docx

pdf_convert2pptx

pdf_compress

pdf_secure

pdf_crack

pdf_create

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pdf_compare_files

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This course will provide you with hands-on experience in PDF manipulation using the Python programming language. It integrates the most common real-life scenarios into its proceedings and supplies you with a framework of "how to do it". 

This course is addressed to Python programmers who seek to broaden their knowledge in the Python programming language. Moreover, it targets those who are eager to gain in-depth experience in handling and processing PDF files which constitute a large part of our day-to-day lives.

PDF Management in Python

# Introduction ##

The PDF file format is simple by design. This encourages developers to create PDF documents using in-house solutions, without relying on external toolkits.

We will be manipulating PDF files later in the course, but knowing the different types of PDF files is a pre-requisite to discern which processing functions apply to each PDF type.
 
This lesson will explore the various types of PDF file formats and peek into their internals. 

# Types ##

PDF files are subdivided into three main types: image-only, searchable image, and formatted text and graphics. 

* ### Image-only PDF ###

An **image-only PDF** (also known as a **Scanned PDF**) includes a photographic image representing each page, and virtually no textual characters or vector graphics. 
Image-only PDF files are not editable and are generally created by scanning hard-copy documents.
 
It may be possible to use Optical Character Recognition (OCR) software to gather the content of an image-only PDF file. However,  the extracted text usually contains recognition errors that require manual proofreading and adjustment to be accurate.
Scanning documents into image-only PDF files has been a standard way of keeping information for archival purposes because electronic media is much smaller and less cumbersome than paper storage.

* ### Searchable image ###

The **searchable-image PDF** (also known as **OCRed PDF** or **made-searchable PDF**) incorporates an image for each page, but this type also contains a text layer. The textual characters are produced from an OCR process, which analyzes each page or image for characters. Wherever characters are detected in the image, the software draws a layer of text under them. An observer of the page sees the surface image only, as with image-only PDF.
The text layer allows a PDF file to be searched for pertinent phrases to a reader viewing the document. It also lets PDF files be indexed with keywords in a collection of electronic documents, lessening the searchability of a PDF file and improving its accessibility.

* ### Formatted text and graphics ###

The **formatted text and graphics** type, also known as **True PDF**, **digitally created PDF**, **text-based PDF**, or **Real PDF**, reduces the use of photographic images. Textual characters and vector graphics are portrayed wherever they can represent the content of a page. Photographic images are used only when they are pictures that cannot be generated from building blocks of textual characters and vector graphics. In general, this type of PDF is the result of a conversion from another electronic file format, such as MS Word. This type is the most compact, often 10% of an image-only file with the same content. 
This type constitutes formatted text and graphics, and offers many features, like accessibility, because of the quality of the underlying text. It also offers more flexibility since it enables converting a PDF file into HTML for rendering as web pages, or transforming into an MS Word document, for editing as part of another document.

This subdivision depends on the originating source of the PDF, and indicates whether its content can be accessed, searched, copied, edited, or whether it is locked in an image of the page.

When it comes to purpose and functionality, and as we will find in the upcoming lessons, these three types may fall into two main categories: searchable and non-searchable PDFs. 
The following table highlights the differences between both categories:

| Feature  | Searchable PDF | Non-searchable PDF |
|:-|:-|:-| - | - |  - | 
| Contains actual text  | Yes | No |
| Contains graphics and images| Yes | Yes |
| Contains links | Yes | No |
| Text can be annotated | Yes | No, except with OCR|
| Text can be redacted | Yes | No, except with OCR|
| Content searchable | Yes | No, except with OCR|
|Can be converted back to MS Excel or MS Word | Yes | No |

# Structure ##

A PDF document is composed of 4 main parts:
* ### The header ###
The first line of the PDF specifies the version of a PDF file format. These headers are the topmost portion of a document. 
It reveals the basic information of a PDF file, for example, "%PDF-1.4", which means that this PDF format is the fourth version. 
* ### The body ###
It consists of objects that compose the content of the document. These objects include image data, fonts, annotations, text streams, and so on. Users can also integrate invisible objects or elements. These objects embed the interactive features in a document like animation or graphics. A user can also impose a logical structure on the document. The logical structure provides a mechanism for incorporating structural information about a document's content into a PDF file, and allows the writer to choose what structural information to include and how to represent it. 

Moreover, we can also make the content of a PDF document more secure by implementing security features. These security features include protecting the PDF file using a password to restrict the unauthorized viewing or editing of this file. 
 
* ### The cross-reference table (xref) ###
The **cross-reference table (Xref)** consists of links to all the objects or elements in a file. When you update a PDF file, the Xref table will automatically get updated. You can also trace the updated changes in the cross-reference table.

* ### The trailer ###
The **trailer** contains links to the cross-reference table and always includes "%%EOF" to identify the end of a PDF file.

Explore the various types and structure of a PDF.

The Types and Structure of PDF Files

Introduction

PDF Management Core Functions

Pages Processing

Content Processing

Document Processing

Conclusion

Appendices

Types and Structure of PDF Files

Introduction