Introduction to Graphics. Terms n Computer Aided Design (CAD) –using computer graphics to draft a...

Introduction to Graphics

Terms

Computer Aided Design (CAD)– using computer graphics to draft a model, can

be tested on screen

Computer Aided Manufacturing (CAM)– integrating the CAD information to determine

the best overall manufacturing procedures

CAD/CAM

Terms

Pixel– Short for “Picture Element”, it is the smallest

unit that appears on the Visual Display Unit

Resolution (解像度 )– the maximum number of pixels that can be disp

layed on a VDU, e.g., 800 x 600

Terms

Bitmap graphics (點陣圖像 )– defines image as a collection of dots (pixels)

– image generally requires more storage space

Terms

Bitmap graphics– used in painting software such as:

• MS Paint, PC Paint Brush, etc.

– scanner, digital camera and fax machine use bitmap graphics to produce/store images

Bitmap Graphics - Example

Smoothnesscannot be maintained when the image is enlarged.

Terms

Vector graphics (向量圖像 )– defines image mathematically as a set of instruc

tions for creating the object in the image

– e.g., rectangle(top, left, bottom, right, line_style, color, …)

(0, 0)

(50, 20)

Terms

Vector graphics– image generally requires less storage space

– used in drawing software such as:• PowerPoint, CorelDraw, etc.

– most clipart images use vector graphic format.

Vector Graphics - Example

As the image is mathematically defined, smoothnesscan be maintained whenthe image is enlarged.

Comparison

Vector Graphics Bitmap Graphics

Object oriented

Less storage space

Less special screen effects

Pixel oriented

More storage space

More special screen effects

Edit pixel individuallyEdit whole object

File Type

Vector Graphics Bitmap Graphics

WMF GIF

JPEG/JPG

BMP

Terms

Object– a component defined in vector graphic software

such as drawings, text, chart and clipart, etc.

Texts

Terms

Attribute (屬性 )– an object’s properties

• i.e., line color, shadow, filled color, etc.

Terms

Handlea small square that appears on the edge when an object is selected

controlling the size of the object

Presentation Graphics

PowerPoint is a presentation graphics software

Enables you to prepare slide presentation

Making Slide Show

opens a new document switches to “Outline” view organises your outlines applies appropriate slide layout applies appropriate slide design

Slide Show Effects

Transition effect– how the slide is changed

Build effect– how the bulleted text and other objects are

shown

Adding Effect

switches to “Slide Sorter” view selects effect from “Transition” tool box selects effect from “Build” tool box if there

are bulleted texts

Adding Custom Effect

PowerPoint also enables you to add custom animation effect to your slide object by right - clicking the object and selects “Custom Animation”.

Inserting Objects

Objects– clipart– chart– graphic image– sound

Menu Command– Insert (插入 ) >> Objects (物件 )

Exporting Graphics Image

PowerPoint supports GIF & JPEG graphics format, you can export your slide(s) by modifying the “File Type” in “Save As…” menu command.

Importing Text

Text can be imported to your slide by executing the following menu commands:– Insert > Object > MS Word Document

When the object shown, executes the following menu commands to import text:– Insert > File

Questions

Give 3 differences between a vector graphics and bitmap graphics software.

Explain why an image created by a low resolution graphics program will normally not be made sharper even if it is imported to a high resolution graphics program.