Mastering Flash Curves
Several methods can be applied to deal with curves in Flash. Typically, designers talk in terms of control handles and points on a curve. That's a job for the Pen or Subselect tool, both of which are found on the main toolbar.
Recall that the curves and lines that define your artwork also can be manipulated freeform by simply dragging or tugging at a curve with the Arrow tool.
Adjusting Curves Without a Handle
Using the Arrow tool, you can modify just about any type of shape, curve, or line segment you can create in Flash. In fact, you can take curves created with the Pen tool using handles and anchor points, and modify those curves freeform by clicking and dragging certain points of the curve with the Arrow tool.
It's not easy, though. Curves tend to behave in ways you might not have anticipated as you stretch and bend them with the Arrow tool. And in particular, if you are used to making adjustments with a Bézier pen tool in other design programs, you probably are better off changing the curve using guides and handles.
For those developers with less predisposed tastes, Flash does offer a simple solution to a fairly complex process. Simply click and drag any portion of the curve to pull it out of alignment and reset its course. You can't, however, always manage the exact behavior of the line: Flash has its own rules governing how the curve will react when you move it around.
Identifying and Relocating Corners and End Points
A complex curve might appear to be rendering as a uniform segment, but most likely, more than one curve is defining the end shape. Flash tends to break curves into simple sections, and often what you see in front of you is not what you will find when you begin exploring that curve.
Using the Arrow tool, you can identify corners and end points in the segment. As you run the cursor across the curve, shapes appear below iteither a curve or a right angle, as shown in Figure 3.8. When the curve is active, you still have a uniform section. But when the corner icon appears, you have reached a break in the curve.
Figure 3.8 On the left is a picture of the cursor when it has identified a curve. On the right, the cursor is over a corner point.
The break in the curve can be exploited in one of two ways. First, if you simply click and release, you notice that only part of the curve is highlighted. In effect, this spot becomes an end point, and you can move that segment elsewhere on the stage. Or you can click and drag. The corner follows your cursor, redefining the angle as you move.
You can tell that you are working with a corner instead of a part of a curve because a hollow circle appears at the focus point you are trying to control.
A true end point, the actual end of the curve itself, also behaves in the same way. Notice also that a small hollow dot appears when you are moving a corner or an end point.
Straightening, Smoothing, and Optimizing Curves
It is vital to realize that complex geometries composed of many curve segments seriously bog down your movie during playback.
Remember that Flash uses math to define its content. Although the curves that Flash renders mathematically are not as complex as in some other programs, they still require processing power to render.
Several tools can be applied to lessen the complexity of your curves:
SmoothWith your curve highlighted, select Modify, Smooth from the main menu to remove tiny bumps and divots that might be unnecessary from a design perspective. This removes unnecessary points and, therefore, unwanted data in your final movie.
StraightenThis option under Modify, Straighten in the main menu has a similar effect on the total number of points in your curve. Unlike Smooth, though, it reduces the geometry by pushing your curve toward a more linear representationsomething you might not want in your final rendering.
OptimizeThis utility is, in effect, a smoothing tool, but with more control and metrics. Choose Modify, Optimize from the main menu to open the Optimize Curves dialog box, which includes several options, as shown in Figure 3.9. First, the Smoothing slider lets you decide how serious you are about removing small imperfections from your curve. You can select the Use Multiple Passes check box to continue to hammer away on the curve until no additional optimization is possible. The Show Totals Message check box produces a message after the process is complete, telling you how many curves were in the original, how many curves resulted after optimization, and the percentage changed.
Figure 3.9 The Optimize Curves dialog box lets you set several parameters that can enhance your final output.