Convert XML DOCBOOK to PPM

DocBook XML, a subset of XML (Extensible Markup Language), serves as a markup language tailored for technical documentation. Developed in the early 90s, it was designed to standardize documentation across various software systems. Its uses include creating structured documents like books, articles, and manuals, ensuring consistency and ease of content transformation across different formats such as HTML, PDF, and EPUB. This standardization facilitates collaboration among developers and writers, enhances content reuse, and simplifies documentation maintenance.

The Portable Pixmap (PPM) file extension, an image format within the Netpbm family, stores simple, uncompressed images. Introduced in the late 1980s, PPM supports RGB color and grayscale images, making it suitable for basic image processing and conversion tasks. Its plain text encoding simplifies debugging and data manipulation, although its lack of compression results in larger file sizes compared to modern formats. As such, PPM finds limited use in contemporary applications, mainly in educational and experimental settings where ease of implementation and readability are prioritized.