Pixrect
Sun's raster library of the 1980s: a "pixel rectangle" with an operations table, so the same code could draw into memory and onto any frame buffer, long before X reached Sun.
The Sun-1 of 1982 had a bitmapped display and needed something to draw with. Pixrect was the answer: a struct describing a rectangle of pixels by width, height and depth, plus a pointer to a table of functions, so that a memory pixrect and a pixrect mirroring the frame buffer of a graphics board could be driven by the same calls. The heart of the library was pr_rop, a raster operation in the spirit of BitBLT, with additions for lines, text from pixfont fonts, single pixels and clipping against regions. SunWindows and then SunView sat on top, and the Sun rasterfile image format with its magic number 0x59a66a95 was a pixrect dumped to disk.
Every new graphics board, from the monochrome bwtwo to the colour cgtwo and cgsix, got its own driver in the pixrect table, which kept programs independent of the hardware but tied them to the local screen. When Sun moved to NeWS and then X11 under OpenWindows, the library became baggage: SunOS 4 kept it, Solaris 2 tolerated it and then dropped it.