Objectives
• Develop an understanding of how vector images are created.
• Learn about tool options available in vector editing software.
• Learn about functions such as tracing found in vector software.
• Discover how clip art can be used creatively.
Introduction
You learned in the previous topic how to use bitmap or raster graphics to edit images for your desktop publishing projects.
In this topic you will see how vector graphics can be just as important as part of the design process.
Draw Program
Remember that vector graphics are made up of a series of lines or arcs that are defined mathematically. Changing the size of the lines or arcs modifies the image. It is important to be aware that if you need to make a complete image smaller or larger, all the lines and arcs must be selected before the transformation takes place. For those who are used to working in bitmaps, this requires a change in mindset.
Vectors are edited using drawing programs such as Adobe Illustrator. Other programs such as Adobe Photoshop and Corel Paint Shop Pro incorporate some vectors into images, but they are primarily bitmap software. Microsoft Expression Graphic Designer allows you to work in either a bitmap or a vector layer with all the features available to each.
Illustrations
Before we learn to use the tools and techniques that are possible with a vector drawing program, we will look at an example to see how vectors differ from bitmaps.
Figure 16.1
Vector images may appear similar to bitmap ones, but they are actually created with lines and curves rather than pixels.
Figure 16.2
Vector images allow you to modify separate parts without disturbing the sections adjacent to the parts.
Figure 16.1 appears to be a graphic much like the ones you worked with in the previous topic. In Figure 16.2, notice that the fins have been moved away from the body of the fish. These "fins" are actually a series of curves that can be moved independently of the rest of the image.
Paths
Vector lines or curves are called paths. A path consists of one or more lines or arcs. Notice the bottom fins show a series of dots. These are points or anchors that can be adjusted to change the shape of the path. The beginning and end of each path has an anchor point called an end point.
A path is the term used for the lines or curves created in vector graphics.
An anchor is a point along a line or a curve that can be used to change the shape of a vector.
An end point is an anchor that appears at the start and end of a path.
One of the most common uses of a program such as Adobe Illustrator is in the creation of ads. In the publishing world, most camera-ready ads are Illustrator files that incorporate both vectors and bitmaps. Camera ready means that the desktop publisher has no work that must be done on the ad. It can be placed in a document just as it is. The ability to develop camera-ready artwork is important for many businesses. It provides the business with more control over the image and can greatly reduce the cost of an ad. Time is also saved because it’s not necessary to have the ad created and then submitted for approval. Often one of the tasks assigned to an in-house desktop publisher is the creation of camera-ready ads for use in professional publications.
A corner point is an anchor at a point that changes direction along a path.
A smooth point is an anchor along a curve.
A direction line is a line that appears when a smooth point is selected. The line is used to adjust the shape or angle of a curved vector.
At places along the path where the angle changes, a corner point appears (see Figure 16.3). Smooth points are anchors along the curve of a path.
A path can be open, as in a straight line, or closed as in a circle. Paths that are curved can be changed using direction lines as shown in Figure 16.4. Paths that are lines are changed by moving the end points as shown in Figure 16.5.
Figure 16.3
Corners are points that change directions along a vector path.
Figure 16.4
Direction lines allow you to change the shape of vector curves.
Figure 16.5
Changing the shape of a path can be done easily using anchors and end points.
Figure 16.6
Adobe Illustrator (vector software) and Adobe Photoshop (bitmap software) have toolbars that appear similar.
Tools
There are a wide variety of tools available to use with vector drawings. Many of these are similar to those you have seen in painting programs such as the selection tool, paintbrush, and eyedropper. Figure 16.6 lets you compare the toolbars available in Illustrator and Photoshop.
Shapes
Even though the Shapes tool seems identical to the one you have seen in painting programs, it does not produce the same result. One shape creates a vector and the other creates a bitmap shape. For example, Figure 16.7 shows two polygons. The one on the left is a vector version. The one on the right was created as a bitmap. Other than the anchors at each point, both of them appear the same. If you look at a close-up in Figure 16.8, you will see that the bitmap polygon has a series of jagged edges. In Figure 16.9 the bitmap one is smooth. If you are printing from the vector image, you will get a sharper edge and a smoother image. No matter how much you enlarge the vector image, no jagged edges will ever appear.
Figure 16.7
Both polygons appear on screen to be identical, but they are not.
Figure 16.8
Enlarged bitmap images reveal a series of jagged edges.
Figure 16.9
No matter how much a vector image is enlarged, the edge remains smooth.
Pen Tool
While the Shapes tool provides you with basic figures such as rectangles and ellipses, often you will want to use additional shapes. The Pen tool allows you to draw any shape that you want. Novice users are tempted to click and draw as if they had an actual pen. The result is a series of direction points and curves. Instead it is easier to produce what you want if you begin by clicking on a point and then clicking on the next point, creating a series of anchors.
Live Paint Bucket
The paint bucket in Adobe Illustrator does not function as you might expect. Instead of being able to pour a color into an area as you would in a painting program, you must first convert a vector drawing to Live Paint. If there are any gaps in your drawing, they must be closed before you will be able to pour paint into the image.
