The document discusses key elements of computer graphics, including output primitives such as polylines, text, filled images, and raster images, highlighting their attributes and functions. It also covers various graphics display devices, including CRTs, LCDs, and LEDs, detailing their working mechanisms, advantages, and disadvantages. Overall, it provides foundational knowledge on creating and displaying images using computer graphics technology.

1. Submitted by : Sanskriti Dwivedi (18100BTCSAII02864)
Shri Vaishnav Vidyapeeth Vishwavidyala
Subject: Computer Graphics
Topics:
• Elements of pictures created in computer graphics
• Graphics Display devices

2. 1. Elements of pictures created in computer graphics
Output primitives and attributes:
The Primitives are the simple geometric functions that are
used to generate various Computer Graphics required by the
User. Some most basic Output primitives are point-
position(pixel), and a straight line.
Attributes : Size , Color, Resolution, Depth

3. 1. Elements of pictures created in computer graphics
Output primitives and attributes:
• Polylines
• Text
• Filled Images
• Raster Images

4. I. Polylines
• A continuous line composed of one or more line segments.
• Edge, Vertex
• Attributes : Color, dashing, Thickness, Endpoint Blending

5. II. Text
• A continuous line composed of one or more line segments.
• Display Modes: Text mode, Graphics mode.
• Attributes : Font color, Spacing, orientation,size.
• drawstring(x,y,string)

6. III. Filled Regions
• Filled shape- Boundary polygon.
• The filled region primitive is a d shape filled with some color or pattern.
• fillPolygon(poly, pattern)

7. Filling used for shadow effects

8. IV. Raster Image
• Also called bitmap graphics.
• Hand designed , computed , scanned images.

9. 2. Graphics Display Devices
i. Cathode-Ray Tube(CRT)
ii. Color CRT Monitor
iii. Liquid crystal display(LCD)
iv. Light Emitting Diode(LED)
v. Direct View Storage Tubes(DVST)
vi. Plasma Display
vii.3D Display

10. i. Cathode-ray Tube (CRT)
• CRT stands for Cathode ray tube
• Cathode ray tube is a particular
type of vacuum tube that displays
images when an electron beam
collides on the radiant surface.

11. i. Cathode-ray Tube (CRT)

12. There are two ways to represent an object on the screen:
1. Raster Scan:
• The electron beam moves along the screen. It moves from top to bottom,
covering one line at a time.
• Based on pixel intensity control display as a rectangular box on the screen
called a raster.
• Picture description is stored in the memory area called as Refresh buffer, or
Frame Buffer.
Types of beam refreshing
Vertical Retrace
Horizontal Retrace

13. Advantages:
• Real image
• Many colors to be produced
• Dark scenes can be pictured
Disadvantages:
• Less resolution
• Display picture line by line
• More costly

14. 2. Random Scan
• stroke-writing display or calligraphic display
• electron beam points only to the area in which the picture is to
be drawn
• uses an electron beam like a pencil to make a line image on the
screen.
• The image is constructed from a sequence of straight-line
segments.
• On the screen, each line segment is drawn by the beam to pass
from one point on the screen to the other, where its x & y
coordinates define each point.

15. Advantages:
• High Resolution
• Draw smooth line Drawing
Disadvantages:
• It does only the wireframe.
• It creates complex scenes due
to flicker.

16. ii. Color CRT Monitor
• three basic colors- Red, Green, and Blue.

17. Color producing techniques
Shadow mask method
Beam Penetration method

18. iii. Liquid crystal display (LCD)
• light modulating properties of liquid crystals.
• flat panel display technology
• TFT (Thin Film Transistor)

19. Advantages:
• Produce a bright image
• Energy efficient
• Completely flat screen
Disadvantages:
• Fixed aspect ratio & Resolution
• Lower Contrast
• More Expensive

20. iv. Light Emitting Diode (LED)
• LED is a device which emits when current passes through it.
• TV, smartphones, motor vehicles, traffic light, etc.

21. Advantages:
• The Intensity of light can be controlled.
• Low operational Voltage.
• Capable of handling the high temperature.
Disadvantages:
• More Power Consuming than LCD.