Insert / Delete Control Points

The right-click context menu on a polygon, polyline or freehand annotation offers two shape-editing items that aren't available for simple geometries.

Insert Point Here

Adds a new vertex on the segment nearest the right-click location.

Workflow:

1. Activate the Select tool.
2. Right-click on the annotation — but click on the segment (near an edge), not inside or outside the shape.
3. Choose Insert Point Here.
4. A new vertex is inserted at the projected click location, between the two nearest existing vertices.

The new vertex gets its own orange drag handle immediately. You can move it straight away.

Delete Point

Removes the vertex nearest the right-click location.

Workflow:

1. Select tool active.
2. Right-click near an existing vertex (within 12 px). The Delete Point menu item only appears when you're close to an actual vertex.
3. Choose Delete Point.
4. The vertex is removed. The two neighbouring vertices now connect directly.

Minimum-Point Guards

Spark prevents you from deleting below the minimum required for each shape type:

If you try to delete the last allowed vertex, Spark shows a status message and doesn't perform the delete.

Availability Rules

Insert Point Here is shown when:

• Selected annotation is Polygon / Polyline / Freehand.
• The click position is near any segment (within the 12-px tolerance).

Delete Point is shown when:

• Selected annotation is Polygon / Polyline / Freehand.
• The click position is near an existing vertex (within 12 px).
• Removing the vertex would leave at least the minimum count.

If the menu items don't appear, check these conditions.

How the Segment Projection Works

When you Insert Point Here, Spark:

1. Takes the right-click canvas position.
2. Converts it to page-relative coordinates.
3. Tests every segment of the shape and finds the one where the click projects onto the shortest distance.
4. Places the new vertex at the projection point on that segment.

The result: the inserted vertex is always exactly on the current edge at the click location. The shape's visual doesn't change at insertion — the new vertex lies on the existing edge. You then drag it wherever you want.

Interaction with Vertex Handles

After Insert:

• The orange vertex handles refresh automatically to include the new point.
• You can immediately drag the new vertex (its handle is in the same position as the inserted point).

After Delete:

• The orange vertex handles refresh; the removed handle disappears.
• The selection remains on the annotation; the shape is now simpler.

Undo

Both Insert and Delete Point are undoable. Ctrl+Z restores the vertex at its original index.

Typical Uses

• Adding detail — a polygon you drew too coarsely gets extra vertices to match a curve.
• Removing clutter — a freehand stroke with too many captured points gets simplified.
• Fixing a mistake — accidentally clicked one extra vertex when drawing a polygon; right-click that vertex and delete.