In a polygon parallel translate a line to itself or along axis of connected line

Use Case 1: Parallel translate straight line of a polygon

  1. You have an arbitrary polygon shape.
  2. You want to move a line of that polygon in parallel to itself
    • while your moved line keeps its length,
    • and the connected lines extend/shrink,
    • one connected line keeping its angle
    • the other connected line changing its angle (unless the connected lines are in parallel, see use case 2)

Figma - Parallel translate straight line of a polygon|video, 100%

Use Case 2: Parallel translate straight line along axis of connected line

  1. You have a polygon.
    • In our case a parallelogram.
  2. You want to move a line of that polygon along one of its connected lines (e.g. 17° or 185°)
    • In the case of a parallelogram both connected lines have the same angle (e.g. 69°).
    • in case the connected lines have different angles, and we move along one of the two connected lines, our moved line changes it length as it stays connected at its start and end point during the move.

Figma - Parallel translate line along axis of a connected line|video,100%

Feature proposal: While dragging the line hold down:

  • … modifier-key-1 to “Move along leftmost/topmost connected line”
  • … or modifier-key-2 to “Move along rightmost/bottommost connected line”