Graphics As Objects


The two types of graphics used in Fireworks are bitmap graphics and vector graphics (see Figure 4.1). The simplest way to explain the difference between the two is that bitmap graphics are made up of rows and columns of pixels, whereas vector graphics are made up of points in space that are connected by strokes and then colorized with fills. Each of these elements (points, strokes, and fills) are rendered mathematically on the screen as opposed to being displayed physically as pixels are.

Figure 4.1. Notice the difference in selection between the bitmap graphics on the left and the vector graphics on the right. The bitmap graphics are selected by pixel, whereas the vector graphics are selected as individual objects.


Understanding how Fireworks handles and organizes the elements in your files will help you have a better understanding of how to create graphics for different mediums, as well as increase your productivity.

Bitmap Graphics

If you're familiar with the form of painting called pointillism, where tiny primary-color dots are used to generate secondary colors, then working with bitmap graphics is nothing new. If you've never heard of pointillism, fear not. Simply magnify a bitmap graphic such as a photo to see the individual building blocks, or pixels, that create the graphic, as shown in Figure 4.2.

Figure 4.2. The image on the left is at normal (100%) magnification, whereas the image on the right has been enlarged 800% to show the individual pixels that comprise the image.


Each pixel can have only one color. When these pixels are arranged in rows and columns, the human eye blends the individual colors together to create the illusion of an image.

The more dots that are used to define an area of an image, the higher the overall quality of the image will be. Accordingly, bitmap images are quantified by the relationship between the number of pixels and the size of the image. This is known as resolution and is usually measured in dots per inch (dpi) for print, or pixels per inch (ppi) for the screen.

If you want to edit a bitmap graphic, you have to modify individual pixels. In addition, because a bitmap graphic is rendered with a finite number of pixels, there is no way to enlarge the image without lowering resolution.

Photographs are bitmap images and you will use Fireworks's bitmap tools to modify photographs, as well as use bitmap effects such as blurring and color replacement.

Vector Graphics

Vector graphics rely on mathematical instructions that tell the computer how to draw graphics. As an example, a vector might have instructions such as "Draw a circle, starting 100 pixels to the right and 50 pixels down from the top-left corner, with a radius of 200 pixels; draw a red stroke over the circle path that is 2 pixels wide, and fill the circle with a yellow color."

On the other side of the coin, the bitmap version would just describe the pixels that are white (background), red (stroke), and yellow (fill).

Here's where an important concept comes into play. A vector graphic contains instructions for each object it contains. In the circle example, the instructions would create a circle object. The same file could have a line object, a square object, and a text object. Each object would be completely separate from the others.

Because all vector graphics are independent of each other and because a specific set of directions is used to construct them, they are always editable. In addition, because vector objects are independent of the canvas behind them, they are also independent of a graphic's resolution. That's the beauty of vector graphics: They're scalable, whereas bitmap graphics are not.

Paths Versus Strokes

The basic shape or line of a vector graphic is called a path. Every vector shape is a path. That path is the representation of a mathematical formula.

Accordingly, each path can have several attributes applied to it. These attributes are what you use to change the path and include stroke and fill color. A path's stroke is the coloring that is painted on the path, whereas the path's fill is the color, or pattern, that covers the area enclosed by the path (see Figure 4.3). Fireworks also enables you to add several more attributes to your paths known as effects, such as bevels, glows, drop shadows, and several others.

Figure 4.3. Selecting a polygon helps identify the path, stroke, and fill.


Even if you cannot see a stroke, the path is still there. It's a confusing concept for many, but remember that you can have a path without a visually represented stroke, but you can't have a stroke without a path.

To drive this home another way, modifying paths and modifying strokes are two different things. When you modify a path, you reshape it. When you modify a stroke, you can change its thickness, color, and visual appearance.



Special Edition Using Macromedia Studio 8
Special Edition Using Macromedia Studio 8
ISBN: 0789733854
EAN: 2147483647
Year: 2003
Pages: 337

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