BLT is an extension to Tcl/Tk.  It adds plotting widgets (X-Y graph,
barchart, stripchart), a powerful geometry manager, a new canvas item,
and several new commands to Tk.

Plotting widgets:  graph, barchart, stripchart
Hierarchical list box:  hierbox
Tab set:  tabset
Geometry Manager:  table
Vector Data Object:  vector
Background Program Execution:  bgexec
Busy Command:  busy
New Canvas Item:  eps
Drag & Drop Facility:  drag&drop
Bitmap Command:  bitmap
Miscellaneous Commands:  winop, bltdebug, watch, spline, htext

Homepage:
https://blt.sourceforge.net/
