Post B0OiA6MusFrL9RPZvU by fvzappa@mastodon.sdf.org
 (DIR) More posts by fvzappa@mastodon.sdf.org
 (DIR) Post #B0OiA6MusFrL9RPZvU by fvzappa@mastodon.sdf.org
       2025-11-19T06:10:01Z
       
       1 likes, 1 repeats
       
       I declare that today, Nov. 19, 2025 is the 50th anniversary of BitBLT, a routine so fundamental to computer graphics that we don't even think about it having an origin.  A working (later optimized) implementation was devised on the Xerox Alto by members of the Smalltalk team.  It made it easy to arbitrarily copy and move arbitrary rectangles of bits in a graphical bitmap.  It was this routine that made Smalltalk's graphical interface possible.  Below is part of a PARC-internal memo detailing it:
       
 (DIR) Post #B0OiABLgMGqKb3sACG by fvzappa@mastodon.sdf.org
       2025-11-19T06:13:53Z
       
       0 likes, 0 repeats
       
       BitBLT was implemented in microcode on the Alto and exposed to the end-user as just another assembly language instruction, alongside your regular old Nova instructions -- this is how foundational it was.  And since it was an integral part of the Alto, it enabled all sorts of interesting experimentation with graphics: user interfaces and human/computer interaction, font rasterization, laser printing... maybe a game or three...