XPM

XPM, the X PixMap format, is C source holding an array of strings: the size and color count, a color table keyed by one or more characters, then one string of characters per row. It reads and writes version 3 through the Egami.Formats.Extended package: register it with WithXpm() or WithExtendedFormats() (Extended formats).

Reads	Up to 8 characters a pixel; of each color's keys the color (c), else gray (g, g4) or mono (m); None, #RGB to #RRRRGGGGBBBB and X11 color names, such as light blue and gray50
Writes	Every color of the raster, as many characters a pixel as the count needs; a pixel below half alpha is None; the name and hotspot from XpmDetails
Natural pixel type	Rgba8
FormatInfo	XpmFormat.Info: name XPM, extension .xpm, MIME type image/x-xpixmap

A color name Egami does not know reads as black with the warning Xpm.ColorUnknown, and a pixel that names no color in the table reads as transparent with Xpm.PixelUnknown; a strict read throws for either. The writer needs every pixel before its color table, so the rows wait in memory until the last one. XpmDetails keeps the array's name, the hotspot and the characters a pixel.