it-e-63 Concept of Graphics and Images

Image or Graphic? Technically, neither.[1]If you really want to be strict, computer pictures
are files, the same way WORD documents or solitaire games are files. They're all a bunch of ones
and zeros all in a row. But we do have to communicate with one another so let's decide.
Image. We'll use "image". That seems to cover a wide enough topic range.
"Graphic" is more of an adjective, as in "graphic format." we denote images on the Internet
by their graphic format. GIF is not the name of the image. GIF is the compression factors used to
create the raster format set up by CompuServe.
So, they're all images unless you're talking about something specific.
The images produced in Drawing programs (CorelDraw, Illustrator, Freehand, Designer etc)
are called vectorised graphics. [2]That is, all of the objects shown on the computer monitor are
representations of points and their relationship to each other on the work area, each of which is
stored in the computer as simple values and mathematical equations depicting: the relationship
between each point and the next point referenced to it, and the position (vector) of each point
referenced to a starting corner of the work area.
Bitmap pictures are stored as a vertical and horizontal array of Pixels and stored information
represents the colour of each of these pixels. The resolution of a bitmap picture describes how
many of these pixels exist over a set distance, usually horizontally: ie pixels per inch or pixels per
centimetre. An unaltered bitmap picture of 300 pixels / inch enlarged by 1000% will therefore
still have the same number of pixels across the actual picture area but each represented pixel will
cover a larger area.
[3]At such an enlargement, the picture would be of little use for reproduction unless viewed
from quite a long distance.
Bitmap or Photo-retouching programs are correctly called PAINTING PROGRAMS.
Vectorised drawings on the other hand can be enlarged as much as desired because, although the
above mentioned points on a drawing would be further apart, the relationship of any described line between
the points would always be the same. A single company logo file produced in a Drawing program could be
used for a business card, any brochure or poster, or plotting out to a Screen Print stencil 3 metres (9 feet)
wide, where as bitmap files would have to be created for every size used if practicable.
What is raster, vector, metafile, PDL, VRML, and so forth?
These terms are used to classify the type of data a graphics file contains.
Raster files (also called bitmapped files) contain graphics information described as pixels,
such as photographic images. Vector files contain data described as mathematical equations and

are typically used to store line art and CAD information. Metafiles are formats that may contain
either raster or vector graphics data. Page Description Languages (PDL) are used to describe the
layout of a printed page of graphics and text.
Animation formats are usually collections of raster data that is displayed in a sequence.
Multi-dimensional object formats store graphics data as a collection of objects (data and the code
that manipulates it) that may be rendered (displayed) in a variety of perspectives. Virtual Reality
Modeling Language (VRML) is a 3D, object-oriented language used for describing "virtual
worlds" networked via the Internet and hyperlinked within the World Wide Web. Multimedia file
formats are capable of storing any of the previously mentioned types of data, including sound and
video information.

1, deem  [di:m]
vt. 认为,视作;相信
vi. 认为,持某种看法;作某种评价

2, stems 
n. 茎(stem的复数);树管;阻挡物
v. 起源于(stem的三单形式);除去…的茎;给…装杆;止住
3, wiretap  ['waiə,tæp]
v.&n. 窃听或偷录,窃听情报,窃听装置
4, solitaire  ['sɔlitεə, ,sɔli'tεə]
n. 纸牌

5, denote  [di'nəut]
vt. 表示,指示

6, depict  [di'pikt]
vt. 描述;描画

7, brochure  [bro'ʃur]
n. 手册,小册子

8, plotting  ['plɔtiŋ]
n. 测绘;标图
v. [测] 绘图;密谋(plot的ing形式)

9, stencil  ['stensəl]
n. 模版,蜡纸
vt. 用蜡纸印刷;用模板印刷

10, raster  ['ræstə]
光栅,扫描线


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