Datasheet
raster images, you need to use a higher resolution to begin with. The higher the resolution,
the larger the file size. Figure 1.1 shows what happens when you blow up a raster image.
In light of this limitation, you might wonder why raster images are used. The answer
lies in how these images are generated. Most common raster displays are television or
computer screens. In fact, the term raster originally referred to the display area of a televi-
sion or computer monitor. To form an image, the electronics in these devices essentially
paint it as a grid of red, green, and blue pixels on a glowing screen. Every image generated
by a computer, therefore, must either begin as a raster image or be rasterized as part of
rendering for display.
Vector Images
Vector images are created in a wholly different way. Vector images are created using
mathematical algorithms and geometric functions. Instead of defining the color of each
and every pixel in a grid of a raster image, a vector image uses coordinates and geometric
formulas to plot points that define areas, volumes, and shapes.
Popular vector-based image applications include Illustrator and Flash, as well as practi-
cally all computer-aided design (CAD) programs such as AutoCAD or SolidWorks. These
programs let you define shapes and volumes and add color and texture to them through
their toolsets.
They store the results in files containing coordinates and equations of points in space
and the color values that have been assigned. This vector information is then converted
into raster images (called rasterization) through rendering so you can view the final image
or animation.
Figure 1.1
A raster image at its original size (left) and blown up two to three times (right)
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