5.3.4.1 Points and decorations

• Point

• Decoration point

The Decoration point represents a point with a certain shape. The shape is defined by the number of vertices – zero means a circle, two a segment, three up to one hundred a polygon and more than one hundred a circle again. The size of the decoration point is determined by the value of the “radius” property.

Note: The decorator point is resistant to transformations. This is very useful for decorating many point which should look the same, for example, vertices of a graph.

• Arrow

The arrow is a transformation-resistant decoration, too. It should be positioned on a curve and it adjusts its direction according to the curve's tangent in the snap position. Its appearance can be adjusted by changing the property values (in the Property editor).

Each arrow has four important points - the front point (where the hanger is located), two side points and the back point. By setting up the “arrow-alignment” property, you can specify how the arrow's rotation should be computed. We can align the arrow to the derivation in the front point or force the back point to be in the intersection of the curve and the side points' center line. The second possiblity is useful especially for a very rounded curve. The final rotation can be adjusted with “rotation”.

The front shape of the arrow is controlled by the “arrow-angle” property (half of the angle between the front point and side points), “arrow-length” (distance between that points),“arrow-front” (shape type) and “front-curvature”. The property “back-distance” determines the angle between the back point and side points and the “arrow-back” property determines the back shape of the arrow.

• Intersection point

To create an intersection point, choose two curves whose intersection you want to create. If do not intersect or cease intersecting after a transformation, the intersection point will position itself on a somehow chosen position (the last well-defined intersection position, for example).

Type: intersection
Subtype: intersection
Anchors: curve-1, curve-2
Hanger: center

• n-gon

The n-gon generator creates a regular n-gon with the given number of apices (a closed path of segments). When you switch to this mode, an entry appears in the editor status bar and lets you enter the desired number of apices. Then you choose the center point and the position of one apex.