Understanding the Types of Points

Understanding the Types of Points

If you are familiar with programs such as Macromedia Fireworks, or Adobe Illustrator, you should understand the basic aspects of working with points.

The basics of points

There are three elements to working with points (also called anchor points). There is the point itself, the line segment that connects the point to other points on the path, and point handles that may extend out from the p 18318y248s oint

Figure 1. The different elements that combine to create a path.

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Points and point handles are displayed in the highlight color of the layer that they are on (see page 158).

Handles are nonprinting lines that control the direction along which any path curves. Changing the direction of the handle changes the shape of the path

Figure 2. The results of moving the point handles in the directions indicated.

Point handles are also called Bézier (pronounced Bay-zee-ay) handles. They were named after the French mathematician Pierre Bézier. He invented the mathematical principles that control handles.

Three different types of points make up FreeHand objects: corner points, curve points, and connector points. In order to have a complete understanding of FreeHand, it is vital to understand how these points work.

Corner points

Corner points are anchor points that allow paths to have an abrupt change in direction. Depending on how they were created, there are three different types of corner points: points with no handles, points with two handles, and points with one handle

Figure 3. Corner points are indicated by white squares and can have no handles (left), two handles (middle), or one handle (right).

Curve points

Curve points are anchor points that make a smooth, curved transition along the direction of the path. A curve point has two handles that extend out from both sides of the point. However, unlike corner points that may have two handles, the handles on curve points are linked so that as the handle on one side moves, the handle on the other side also moves. The length of the handle governs the shape of the curve

Figure 4. Curve points are indicated by round dots and always have two point handles that govern the shape of the curve.

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If you rotate the point handle on one sids of a curve point, the handle on the opposite side also moves. It is this "lever" action that makes the curve transition smooth

Figure 5. Rotating one handle of a curve point also moves the handle on the other side.

Connector points

The purpose of connector points is to constrain the transition between segments so that they cannot be moved out of alignment with their line segments . Connector points are indicated by triangular dots and always have point handles.

Figure 6. Connector points are indicated by triangular dots. Their handles stay aligned to the line segment they are connected to.

Connector points can have one or two point handles. When a connector point occurs between a straight-line segment and a curved segment, there is only one point handle, which runs along the same direction as the straight line. When a connector point is between two curved segments, there are two point handles which are constrained by the position of the points on either side of the connector point.

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FreeHand provides two types of handles on the levers that come out of the points. The illustrations in this book show the small handles. You can work with the large handles by switching the Preferences settings (see Appendix C