RAS to PGM Converter

RAS (Sun Raster) is a raster image format developed by Sun Microsystems for their SunOS and Solaris Unix workstations, dating to approximately 1982. Sun Raster files store 2D bitmap images with support for 1-bit monochrome, 8-bit indexed color (with a color map), 24-bit true color (BGR byte order), and 32-bit XBGR (with an unused alpha byte). The format uses a 32-byte header containing a magic number (0x59a66a95), width, height, bit depth, data length, raster type (indicating compression), color map type, and color map length, followed by the optional color map data and the pixel data. RAS supports three encoding modes: standard (uncompressed, with each scanline padded to a 16-bit boundary), byte-encoded (run-length encoded using a simple escape-code scheme), and RGB (uncompressed with RGB rather than BGR byte order). Sun Raster was the native image format for Sun's window system and later the OpenWindows desktop environment, serving as the standard format for screenshots, icons, backgrounds, and application graphics on Sun workstations throughout the 1980s and 1990s. One advantage is the format's representation of Unix workstation computing heritage: Sun Raster files from the SunOS/Solaris era document the visual culture of an important computing platform that drove advances in networking, multiprocessing, and graphics workstation design. The format's straightforward structure is another practical strength — the 32-byte header and simple encoding make RAS files easy to parse and convert, even with custom code. RAS files are supported by ImageMagick, GIMP, XnView, and other image processing tools.