Just as a text editor helps you create or modify text and an image editor helps you create or modify an image (sometimes called a bitmap or raster), a graphics editor helps you create or modify a graphic (sometimes described by the names vector or illustration). Note that editors also exist for the other two media, namely audio and video.
A graphics file represents a picture by storing numbers that describe the individual objects that make up the picture. For example, a circle in a graphics file may be stored as: - two numbers that are the (x,y) coordinates that locate the center of the circle - a number that is the radius of the circle - a number that tells how thick the circle is - a number that specifies the color of the circle - sometimes another number that specifies the color that fills the he circle. - a number that says that this object is a circle. The last number is necessary so that the editor can tell that the object is a circle rather than a rectangle, a line, or some other type of object. Each type of object has its own set of numbers that describe and identify it.
A graphics editor creates these numbers when you ask it to create an object. It also reads these numbers in order to show you the object, correctly positioned relative to the other objects, on the monitor's screen. Thus, you never need to see the numbers. You just see a screen full of graphic objects.
A graphics editor lets you open a file, select any individual object, and change one or more of its numbers, such as enlarging a circle by increasing its radius. This ability is what distinguishes a graphics editor from an image editor. An image editor stores the color of each of thousands or millions of pixels that makes up a picture. Consequently, for example, a circle in an image is no more than a set of particularly colored pixels. If you intend to go back and edit individual objects later, you should use a graphics editor rather than an image editor.
Another advantage of a graphics editor over an image editor is that a simple graphics file tends to be far smaller than does an equivalent uncompressed image file. This is because a graphics file stores a circle as merely a dozen or so numbers, whereas an image file stores a circle as the colors of hundreds or even thousands of separate pixels. Thus, a graphics file tends to occupy far less storage space or network bandwidth than does an uncompressed image file.
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