Midpoint projection on a straight segment
Hovering a straight segment previews a midpoint; pressing it inserts a vertex and begins a drag.
1
Hover
Preview appears
Pointer over a straight segment.
2
Press
Vertex inserted
Pointer-down inserts the vertex.
3
Drag
Translate without release
Same pointer-down continues as a drag.
vertex
selected vertex
midpoint preview (hover only)
segment
previous shape
crosshair