Convert PHM to SIXEL

The PHM file extension stands for Portable Float-map Image (16-bit half), a format used for storing High Dynamic Range (HDR) images with 16-bit half-precision floating-point values. This format is particularly useful in applications requiring precise color representation and extensive dynamic range, such as computer graphics, image processing, and scientific visualization. Originating from the Portable FloatMap (PFM) format, PHM was developed to provide a more efficient storage solution by utilizing half-precision floats, thereby reducing file size while maintaining significant detail and accuracy.

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.