Convert PPM to SIXEL

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.

The SIXEL, or "six pixels", is a bitmap graphics format created by Digital Equipment Corporation (DEC) for their terminals and printers. Initially designed for DEC dot matrix printers like the LA50, it enabled the efficient transfer of bitmap graphics using a series of ASCII characters. Each character represents a 6-pixel high row, making it suitable for 7-bit serial communication. This format was later adapted for modern terminal emulators, extending its utility beyond its original scope.