Regarding the Tektronix 4100-Series terminals, ex-Tek employee Dave Brown recalls:
The 4100 series was an intelligent family of terminals that added segment capability to Tek Graphics. They would fully emulate the 4010/4014 family. Segments allowed you to define a graphic object or string and display it. Rather than going back to the host to redraw, you could change the viewport to zoom and pan and it would do so from the stored data. The 4114 was a DVST so limited to vectors. Others in the family were the 4012 mono raster, 4013 color raster, and 4115 high resolution color with auto convergence. They had some 3D models as well.
With the raster products you had the ability to define polygons and the ordering would handle hidden line and polygons if I remember right. They also handled shading and patterns. As such, I don’t know how much of this propagated to the 4114. I suspect if you defined a polygon it would draw the outline.
Segments could also be stored on the floppy disks and recalled. I suspect you could do forms and such also but after 40 years I just don’t recall the details. I was buried down in the hardware and OS and never really used them for graphics. We might have a brochure on them although the catalogs probably have a good overview description.
I wasn’t close to the vector generator design. I do know you needed it fast and you wanted a constant velocity so line thickness would be uniform. There was usually a lot of circuitry to deal with D/A glitches and the like. Hardcopy and write-through also added challenges. Then of course they had to deal with idiosyncrasies of the 4014. The 4014 supported 132 characters in alpha mode. But you could position the beam at the far right, put it back into alpha, and print a character in the 133 column so of course they had to support that. There were a few others.