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Adobe Illustrator CS5 on Demand: Working with Objects

This chapter from Adobe Illustrator CS5 on Demand explains all of the tools you need to work with objects in Adobe Illustrator.
This chapter is from the book

This chapter is from the book

Introduction

Adobe Illustrator is an application that gives you great control over vector graphics, which include vector shapes and vector objects. Vector graphics are created using mathematical shapes, not pixels, and that’s why vector shapes are considered resolution-independent. When you draw a vector object, you create one or more lines called a path. A path is made up of one or more curved or straight line segments. The start and end points for a line segment is known as an anchor point, which you can drag to change and move.

Illustrator provides drawing tools on the Tools panel that you can use to create a variety of shapes, including rectangles, rounded rectangles, ellipses, polygons, stars, flares, lines, arcs, spirals, rectangle grids, and polar (circular) grids. After you draw an object, you can use Illustrator selection tools to modify it. The two main selection tools are the Selection tool and the Direct Selection tool. The Selection tool allows you to select entire objects, while the Direct Selection tool allows you to select paths and segments. In addition to these tools, you can also use the Select menu. The Select menu provides a variety of powerful selection commands for you to use in a document or artboard. For example, you can select objects whose attributes (including Appearance, Blending Modes, Fill & Stroke, Opacity, and Stroke Color) are similar to the current or last selection.

After you select one or more objects, you can move, align, group, and transform them. The transformation tools allow you to rotate, scale (resize), reflect (mirror image), or shear (slant) an object.

Understanding Vector and Raster Graphics

Illustrator is an application that gives you great control over vector graphics, which include vector shapes and vector objects. Vector graphics are created using mathematical shapes, not pixels, and that’s why vector shapes are considered resolution-independent. For example, if you enlarge a vector image to 100 times its original size, Illustrator merely changes the mathematical formulas to reflect the new size, and since vector shapes are constructed of mathematical data instead of pixels, file sizes are extremely small.

Raster graphics, such as bitmaps and photographs, are images creating using individual pixels that identify one piece of color information. The reason raster images are considered resolution-dependent is that once the image is created or scanned, any enlargement of the image forces Illustrator to enlarge and average the existing color information in the document. This process, called interpolation, is what causes enlarged raster images to become blurred, or pixelated.

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