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Chapter 7. Drawing Vector Shapes
For many years, vector graphicswhich are made up of mathematically defined lines and fillswere considered a "poor cousin" to bitmapped graphics. (For more on the difference between vectors and bitmaps, see the "Vectors Compared with Bitmaps" sidebar later in this chapter.) Because they lack the subtlety and texture of bitmapped images, vector images were used primarily for technical illustration, where aesthetic considerations were less important.Director had no vector drawing capability at all until the Vector Shape window was added in version 7. This late addition was most likely a response to the boost in popularity that vector graphics received from the success of Macromedia Flash.Flashwhose developers had realized that vector graphics, with their minimal data requirements, were ideal for use on the Webwas designed from the beginning with vectors in mind. It included a set of high-powered drawing tools that made vector artwork, which had previously been somewhat tricky to create, as easy to draw as bitmapped artwork.Director's Vector Shape window gives Director users, like Flash users, the ability to use vector images in their movies. Other than that, however, Director's implementation of vector graphics is rudimentary. Director's vector drawing tools, in strong contrast to Flash's, are cumbersome to use and extremely limited in what they can do. In addition, Director offers virtually no support for importing vector images. (With the exception of vector PICT files, a rare and outdated format limited to the Mac, Director can import vector images only if they're included in Flash SWF files.)If you want to do any sort of serious vector animation, use Flash. Flash movies can be imported into Director in their entirety, allowing them to be integrated fully with your Director movies. (See Chapter 11, "Using Flash Movies in Director.") Use Director's Vector Shape window only when you need simple, no-frills vector shapes that can be edited within Director.
Vectors Compared with BitmapsA bitmapped graphicthe kind of image you've worked with so far in this bookis a rectangular array of pixels (Figure 7.1). The visual content of a bitmapped graphic is created by changing the colors of individual pixels in the rectangle. Bitmapped graphics are created in image-editing programs such as Photoshop and Fireworks, or in Director's Paint window. Figure 7.1. A bitmapped circle is made from a rectangular array of square pixels, colored to approximate a circle. A vector circle is an actual, mathematically defined circle. A vector graphic is a set of mathematical instructions for drawing and filling geometric shapes. The software that displays vector graphics must do the "work" of converting those instructions into a visual image. Hence, vector graphics put more of a load on the processor than bitmapped graphics do. Vector graphics are created in illustration programs such as Illustrator or Freehand, in Flash, or in Director's Vector Shape Window.Functionally, bitmapped and vector graphics differ in two major ways: File size: A bitmapped graphic file has to store information about each individual pixel in the image. As the dimensions of a bitmapped graphic increase, the file size increases balloons even more rapidly. (For example, a 10-by-10-pixel image contains 100 pixels, but a 20-by-20-pixel image contains 400 pixels.) A vector graphic file, by contrast, contains only mathematical formulas, which don't take up much space to begin with and which remain the same size regardless of the size of the image. Scalability: When you enlarge a bitmapped image, the image-editing software has to make educated guesses about where and how to insert pixels. The result of this guesswork is usually roughness and jagged edgescalled jaggies. When a vector graphic is enlarged, there is no guesswork: New values are inserted in the formulas, but the formulas remain the same, so the vector image retains its quality at any size. |
