Connectors have no right answer, only exact coordinates
Drawing a single line on a flowchart involves several decisions: solid or dashed, arrowhead or none, a right-angle turn or a diagonal run. None of them has an accepted standard, so no tool can settle them for you. What can be calculated exactly is the geometry. This tool lists the decisions and works the bend points out from the two node positions.
How it is calculated
Horizontal first places the bend where the end node x meets the start node y, and vertical first does the opposite. The S shape turns twice at the midpoint between the two x values. The path length is the sum of the legs, and the angle is the direction from start to end on screen axes. A corner radius fits only up to the length of the legs at each bend (half for a middle leg that bends at both ends), so that limit is reported alongside. The path string in the result pastes straight into SVG. Written as of October 2026.
Limits
No line style or arrowhead is recommended. Working out where a line meets a node border, automatic routing, obstacle avoidance and emitting a path with the rounded arcs already applied are not supported.
Frequently asked questions
There is none. What a solid or dashed line means, and what each arrowhead shape implies, differs between notations. What matters is fixing one meaning per diagram, and this tool only lists the decisions to make.
The bend point moves. Horizontal first turns where the end node x meets the start node y, and vertical first does the opposite. The total path length is the same, but the line passes through different space, so one option may collide with a node.
Each bend trims the radius from the legs on either side and replaces the corner with an arc. A middle leg that bends at both ends (the vertical leg of an S shape) is shared by two arcs, so it allows up to half its length. An end leg that bends at one end only allows its full length. Past that, the arcs overlap or overshoot the node and the line looks broken.