QUESTION: What is the difference between a
bitmap graphic format and a vector graphic format?
ANSWER: The terms "bitmap" and
"vector" refer to the two basic methods of describing
graphics digitally.
Bitmap:
A bitmap description describes a graphic as a grid with thousands
or millions of dots. The dots are called "pixels."
In the simplest kind of bitmap description,
some of the pixels are "on" (black) and some of them
are "off" (white). Things get a little more complicated
when you are talking about a color graphic as opposed to a
black-and-white graphic, but the principle is the same.
A very simple bitmap description of a square outlined in black
might look something like this:
000000000000000000000
000000000000000000000
001111111111111111100
001000000000000000100
001000000000000000100
001000000000000000100
001000000000000000100
001000000000000000100
001000000000000000100
001111111111111111100
000000000000000000000
000000000000000000000
Each digit "1" represents a pixel that is black, and
each digit "0" (zero) represents a pixel that is white.
Another name for bitmap graphics is raster graphics.
GIF, TIFF, JPEG and BMP files are all bitmap-format files.
Some applications that can create bitmap-format files are Adobe
Photoshop, Adobe ImageReady, Imaging for Windows, and Windows Paint.
Vector:
A vector description uses a programming language to describe
a graphic in geometric terms.
For example, a vector description of a square might say: "At
a point three inches in from the left edge of the paper and four
inches up from the bottom of the paper, draw
a two-inch square and outline it with
a black line 1/4 inch wide." In programming language, this
vector description might look something like the following:
moveto 3 inch 4 inch
lineto 5 inch 4 inch
lineto 5 inch 6 inch
lineto 3 inch 6 inch
lineto 3 inch 4 inch
setlinewidth .25 inch
stroke
HPGL files and CAD files are vector-format files. Some applications
that can create vector-format files are AutoCAD, Adobe Illustrator, and
CorelDRAW.
Some types of files can be bitmap-format files, vector-format files,
or both. For example, an EPS file or a PDF file can contain
descriptions of text and graphics in both bitmap format and
vector format.
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