Introduction to Computer Graphics – SS1 Visual Arts Lesson Note (Second Term)

Computer graphics is the creation of graphic work such as drawings, logos and photographs on a computer. It needs hardware, the visible parts of the computer such as the monitor, keyboard, mouse and scanner, and software, the programs such as Corel Draw and Adobe Photoshop that run on it.

Behavioural objectives

By the end of the lesson, students should be able to:

1. name and describe the main computer hardware devices used in graphics;
2. classify hardware devices as input or output devices;
3. explain what computer software is;
4. distinguish between system software and application software, and give examples of application software;
5. describe the four basic mouse techniques.

What is computer hardware?

Computer hardware is the visible and tangible components of a computer. The main parts used in graphics are listed below.

1. Monitor: a primary output device that displays information or graphic work on a screen, like a television set.
2. System unit: the computer casing or cabinet that holds the central processing unit (CPU) and many other electronic components.
3. Printer: an output device that prints your graphic work on paper.
4. Keyboard: an input device that looks like a typewriter keyboard and has numerical keys, special character keys, control keys and function keys for typing text and issuing commands.
5. Mouse: a hand-held pointing device that lets you point to, select and move objects on the screen.
6. Scanner: an input device that copies images such as a photograph, logo or drawing and changes them into a form the computer can store and edit.
7. Diskettes: magnetic disks used to store information. Flash drives have now largely replaced them.

What is the difference between input and output devices?

An input device sends data into the computer, while an output device shows or produces the result of the computer’s work.

• Input device: you use it to enter text, images or commands, for example the keyboard, mouse and scanner.
• Output device: it presents finished work to the user, for example the monitor and printer.

What is computer software?

Software is the invisible part of a computer system, made up of programs designed to run on a particular system.

• Invisible: you cannot touch software, but you see its results on the screen.
• Programs: they are sets of instructions that tell the hardware what to do.
• Two kinds: software is either system software or application software.

What are the types of computer software?

There are two types of computer software: system software and application software.

System software

• Meaning: it controls the computer system and keeps the hardware working.
• Example: an operating system such as Windows.
• Need: the computer cannot run application software without it.

Application software

• Meaning: it is used with system software to perform specific tasks given to the computer by the user.
• Corel Draw: used to draw and design logos, posters and other artwork.
• Adobe Photoshop: used to edit and improve photographs.
• Harvard Graphics: used to produce charts and presentation graphics.
• Eye-Candy: used to add special effects to images.

What are the four basic mouse techniques?

The four basic mouse techniques are pointing, clicking, double-clicking, and dragging and dropping.

1. Pointing
2. Clicking
3. Double-clicking
4. Dragging and dropping

What is pointing?

Pointing means moving the mouse until the pointer on the screen rests on the object of interest.

What is clicking?

Clicking means pointing to an item and quickly pressing and releasing a mouse button. There are two types of clicking:

• Left clicking: you press the left button while the pointer is over an object to select it.
• Right clicking: you press the right button while the pointer is over an object to bring up a menu of options.

What is double-clicking?

Double-clicking means pressing the mouse button twice very fast.

• Use: it is commonly used to open a file, folder or program.

What is dragging and dropping?

Dragging and dropping means moving an object to a new place on the screen while holding down the mouse button.

1. Point to the object.
2. Press and hold down the mouse button to grab the object.
3. Move the mouse to drag the object to the new place.
4. Release the button to drop the object.

Evaluation

1. What is computer hardware? Name six examples.
2. State the functions of the monitor, the printer and the scanner.
3. What is the difference between system software and application software?
4. List four examples of application software.
5. Describe the two types of clicking.

Assignment

List the four basic mouse techniques and explain each one in a sentence. Then describe the keyboard and the system unit in your own words.