Ink-jet Printers
Ink-jet printers work in the same way as dot-matrix printers do to
form images or characters with little dots. However, the dots are
formed by tiny droplets of ink. Ink-jet printers form characters
on paper by spraying ink from tiny nozzles through an electrical
field that arranges the charged ink particles into characters at the
rate of approximately 250 characters per second. Various colours of ink can also be used
in these printers. These printers are cheaper and portable as compared to non-impact
printers.
Laser Printer
Laser printers are the popular non-impact printers that produce
images with the help of laser beam. It works like a photocopy
machine. Laser printers produce images on paper by directing a
laser beam at a mirror which bounces the beam onto a drum. The
drum has a special coating on it to which toner (an ink powder)
sticks. Using patterns of small dots, a laser beam conveys information from the computer
to a positively charged drum to become neutralized. Laser printers have a high speed and
resolution. They produce high quality printing without producing any noise.
Plotter
Plotter is a device used to print high quality images
and graphics. It uses one or more pens to produce a high quality
drawing. Plotters were the first type of printers that could
print with colour and render graphics and full-size engineering
drawings. Plotters are much more expensive than printers. They
are most frequently used for CAE (Computer Aided Engineering) applications, such as
CAD(Computer Aided Design) and CAM (Computer Aided Manufacturing). Instead
of toner, plotters use a pen, pencil, marker, or another writing tool to draw multiple,
continuous lines onto paper rather than a series of dots like a traditional printer.
Speaker
Speakers are popular output devices used with computer systems.
They receive audio input from the computer’s sound card and
produce audio output in the form of sound waves. Most computer
speakers are active speakers, they have an internal amplifier which
allows to increase the volume, or amplitude, of the sound. Speakers usually come in a
pair, which allows them to produce stereo sound from two separate audio channels.
50 New Gateway to Computer Science Book -9
Let’s Review
The output that we get from a printer or a plotter on a paper is also known as
hardcopy output.
Impact printers are those printers in which mechanical contact between print head
and paper exists.
A daisy wheel printer is an impact printer that produces printout of good quality
character.
A drum printer consists of a solid, cylindrical drum that has raised characters in
bands on its surface.
Non-impact printers are the printers in which mechanical contact between the
print head and paper does not exist.
Laser printers produce images on paper by directing a laser beam at a mirror which
bounces the beam onto a drum.
Plotter is a device used to print high quality images and graphics.
Computer speakers receive an audio input from the computer’s sound card and
produce audio output in the form of sound waves.
Expand your knowledge
The mouse was invented by Douglas Engelbart in 1964 AD.
During the mid and late 1700s and early 1800s, several typing and writing
devices were created around the world.
The first practical typewriter and the word "Type-Writer" was first developed
in 1868 by Christopher Sholes and is considered to be the first typewriter.
The first digital computer known as the ENIAC that was completed in 1946
used a teletype machine to input data into the computer.
In 1984, Apple Computers released the Macintosh personal computer. It was
the first computer that came with 128KB of memory.
In 1975, personal consumer computer Altair released, it uses Intel's 8-bit
8080 processor and includes 1 KB of memory.
Assignment
1. Select the correct answer from the given options.
a. Which of the following is a computer hardware?
i. Keyboard ii. Monitor iii. Mouse iv. All of the above
b. Which of the following helps to install the processor into the motherboard?
i. CPU socket ii. RAM iii. AT connector iv. Expansion cards
New Gateway to Computer Science Book -9 51
c. Which of the following is the latest connectors with 7 pin interface?
i. AT connector ii. ATX connector iii. SATA connector iv. None of them
d. From where does the motherboard get the power connection?
i. Expansion slot ii. Power connectors iii. RAM slot iv. CPU socket
e. For what can we use IDE connector?
i. FDD & HDD ii. Mouse & Keyboard iii. RAM & ROM iv. CPU socket
f. Which of the following is a primary memory?
i. RAM ii. Hard Disk iii. ROM iv. Magnetic tapa
g. Which of the following is called a flash memory?
i. Pen drive ii. Compact disk iii. Hard disk iv. Motherboard
h. Which of the following represents the binary digits?
i. 0 &2 ii. 0 & 1 iii. Only 0 iv. Only 1
i. Which of the following is the largest memory measurement unit?
i. Bits ii. Bytes iii. Kilobytes iv. Nibble
j. Which of the following is a hardcopy output device?
i. Monitor ii. CPU iii. Printer iv. Scanner
2. Fill in the blanks with suitable words.
a. …………………. is the collection of physical components that constitutes a
computer system.
b. A …………………. provides the electrical connections by which the other
components of the system communicate.
c. CPU socket helps to install the processor into the ………………….
d. RAM is the …………………… memory of the computer.
e. A Motherboard needs the power to keep running and it gets the power
from………………...
f. …………………….. is the collection of physical components that constitutes a
computer system.
g. A…………….. provides the electrical connections by which the other components
of the system communicate.
52 New Gateway to Computer Science Book -9
h. The first microprocessor was the ………………….., introduced in 1971 AD.
i. Primary memories are called …………………….
j. The contents of secondary memories are first transferred to the ……………………,
and then the CPU can access it.
3. State whether the given statements are true or false.
a. AT connector is one of the connectors which has 2 numbers of 6 pin male
connectors.
b. The first microprocessor was introduced in 1620 AD.
c. CPU socket helps to install the processor into the Motherboard.
d. A Motherboard needs the power to keep running and it gets the power from RAM.
e. Microprocessor consists of an ALU, register array, and a control unit.
f. ALU, registers, internal bus and control sections are the functional sections of
microprocessor.
g. RAM is a non-volatile memory of the computer system.
h. Cache memory acts as a buffer between the CPU and the main memory.
i. ROM is called volatile memory because it never loses its contents.
j. Speaker is one of the popular input devices of computer system.
4. Write appropriate technical terms for the followings.
a. A connector used to connect the disk driver including floppy disk drive and hard
disk drive. ‘
b. The section of CPU which is used to calculate the ability of the microprocessor to
perform either arithmetic or logical operations.
c. It is one or more sets of chips that store data or program instructions, either
permanently or temporarily.
d. It is a small, fast and expensive semiconductor memory that stores the copies of
data that needs to be accessed frequently from the main memory.
e. These are plastic tapes with magnetic coating that are used for storing the data,
such as text, audio or video.
f. It is an optical storage device which reads data faster than a CD.
g. A group of 8 bits.
h. A pointing device that usually consists of one or more buttons and a stick which
controls the movement of the cursor on the screen by pointing in all directions.
New Gateway to Computer Science Book -9 53
i. Barcode is a set of small bars of varying thickness and spacing printed on the
packages of products, on the back cover pages of books, tags, etc.
j. A monitor technology that uses liquid crystals technology to display the output.
k. The printer that uses print heads containing 9 to 24 pins.
l. A printer consists of a solid, cylindrical drum that has raised characters in bands
on its surface.
m. A device used to print high quality images and graphics which uses one or more
pens to produce a high quality drawing.
5. Write the full form of the followings.
HDD, FDD, RAM, ROM, SMPS, IDE, LED, DRAM, SDRAM, PROM,
EPROM, EEPROM, CD-ROM, RPM, DVD, OMR, OCR, QR-Code
6. Match the following.
RAM Input device
Hard disk Place on CPU socket
Plotter Called flash drive
Pen drive Hardcopy output
Microprocessor Storage device
Touchpad Permanent memory
7. Answer the following questions.
a. What is computer hardware? Write its types.
b. What is motherboard? What does it provide?
c. Name any six components of motherboard.
d. What is the use of expansion card slot?
e. What is microprocessor? Write down the functional sections of microprocessor
and also wite its functions.
f. What is secondary memory?
g. What is primary memory? Maintain its types.
h. What is cache memory? Write its advantages.
i. Write down the characteristics of secondary memory.
j. What is magnetic storage device? Define magnetic tape.
54 New Gateway to Computer Science Book -9
k. What are the advantages and disadvantages of using magnetic tape?
l. What is hard disk? List out its basic components.
m. What is optical disk? Write and define its types.
n. List out the memory measurement units with their bytes.
o. Define DVD and blue-ray Disk.
p. What is keyboard? Explain the types of various keys.
q. What are the differences between mouse and light pen?
r. Define joystick, scanner and touch pad.
s. What is OCR and Bar Code? Define touch screen technology and QR code scanner.
u. Define output devices with their types.
v. Explain in short about soft copy output and hardcopy output with examples.
w. What is LED and LCD technology in the sense of monitor?
x. What is impact and non-impact printer? Write with examples.
y. Explain any two output devices in short.
z. What is chain printer and drum printer? Write its range of speed per minute.
Project Work
• Prepare a project report about the types of input and output computer hardware.
• Visit IT solution office like computer sales and maintenance centre, mobile sales and
maintenance centre and collect the latest devices that are available there.
New Gateway to Computer Science Book -9 55
Lesson
5 Introduction to Computer Software
Inside the Lesson
Introduction to computer software
Types of computer software
System software
Operating system, its functions and types
Utility programs
Device drivers
Application software and its types
Introduction to GUI environment
Understanding windows desktop
Mouse pointer and its activities
File and folder management
Working with windows explorer
Language processor
Introduction to open source software with its advantages
Introduction to desktop and web apps
A computer system consists of hardware, the electronic devices that are capable of
computing and manipulating information, and software that carries out predefined tasks
to complete a given task. All computer systems consist of two major components that
are hardware and software. Hardware is the physical component and software is a set of
computer programs which enable hardware to function. We can say that software gives life
to the hardware and therefore, the software is popularly referred to as the soul of the computer
system while the hardware like the heart. We can define, software as the collections
of program and other associated documents that helps to control, manage and integrate
the components of computer system to accomplish a specific task. Computer system is
nothing without the software.
56 New Gateway to Computer Science Book -9
Types of Computer Software
The computer software mainly performs two varieties of tasks. The first task is to control
and coordinate the hardware components and manage their performance and the second
one is to enable the users to accomplish their required task. Different types of computer
softwares are discussed below.
System Software
System softwares are those programs that manage the operating system with the
coordination of computer hardware and their resources. Systems software is a set of
instructions that serves mainly as an intermediary between computer hardware and
application programs. Systems software provides important self regulatory functions for
computer systems, such as loading operating system, managing hardware resources and
providing commonly used sets of instructions for all applications to use. System software
includes:
Operating system
Utility programs
Device drivers
Operating System
Operating sytem is a computer system software that acts as an intermediate between the
user and computer hardware. It controls and co-ordinates the overall operations of the
computer. This is the first software that we see when we turn on the PC. It manages the
computer's memory and co-ordinates with computer software and hardware. What we
can say is that, without an OS computer is just useless. The OS usually comes pre-loaded
on any computer when we purchase it. Most of the people uses the OS that comes with it
but they can change or upgrade as their requirements. Modern OS uses a graphical user
interface system so that it is very easy to use and operate. The OS provides services such
as process management, file management, etc.
Functions of an Operating System
Process Management: Process management means managing the programs that are
running on the processor at a given time. The operating system loads a program into
main memory and executes it. Some operating systems offer more sophisticated forms of
process management, such as multitasking, multithreading, and multiprocessing.
File Management: A file system is normally organized into directories for easy
navigation and usage. These directories may contain files and other directories. It keeps
track of information, location, uses, status, etc. It also allocates and de-allocates the
resources.
New Gateway to Computer Science Book -9 57
Memory Management: Memory management refers to management of primary
memory or main memory. Main memory provides a fast storage that can be accessed
directly by the CPU. If a program needs to be executed, it must be in the main memory.
Interface Between the User and the Hardware: An OS provides an interface between
user and machine. The interface can be Graphical User Interface (GUI) and Command
Line Interface (CLI). In graphical user interface user can click on screen elements to
interact with the OS. Like this, in command line interface user can type commands at the
command line interface to tell the OS to accomplish the task.
Coordinate Hardware Components: An OS enables the coordination of hardware
components. Each hardware device understands a different language, but the operating
system can interact to them through the specific translational software called device
drivers. Every hardware component has different drivers for operating systems. These
drivers make the communication successful between the other software and the hardware.
Let’s Review
Software is the collection of programs and other associated documents that helps
to control, manage and integrate the components of computer system to
accomplish a specific task.
Systems software is a set of instructions that serves mainly as an intermediary
between computer hardware and application programs.
Operating system provides services that include process management, virtual
memory, file management, security and the user interface.
A file system is normally organized into directories for easy navigation and
usage.
An OS provides an interface between user and machine.
Memory management refers to management of primary memory or main memory.
Types of Operating System
As previously discussed, operating systems are necessary for computer hardware to
function. Operating systems can be categorized based on the number of users that they
support. The types of operating systems are explained below.
Real Time operating System
A real-time operating system is a very fast and small operating system. It is defined as a
data processing system in which the time interval is required to process and respond. A
real-time operating system must have well-defined, fixed time constraints, otherwise the
system will fail. For example, scientific experiments, industrial control systems, weapon
systems, robots, air traffic control systems, etc. Real time operating systems are very fast
and quick respondent systems. These systems are used in an environment where a large
number of events must be accepted and processed in a short time.
58 New Gateway to Computer Science Book -9
Single User Single Tasking Operating System
An operating system that allows a single user to perform just one task at a time is called
single user single tasking operating system. In this operating system, only one user can
work at a time. An example of a single-user, single-task operating system is the operating
system used by handheld computers such as Personal Digital Assistants (PDA).
Single-User, Multi-Tasking Operating System
A single-user,multi-tasking operating system is one that allows a single user to perform
two or more functions at a time. It takes special operating system to keep two or more
tasks at once. The most commonly used personal computers usually run such OS are
Microsoft Windows and Macintosh Operating system. The multi-tasking features of these
OS have greatly increased the productivity of people in a large variety of jobs because
they can accomplish more in a shorter period of time. This is the type of operating system
which is popularaly used on the desktop and laptop computers today. For example, it is
possible for a Windows user to work with word processor while downloading a file from
the internet, printing the text, listening to music or sending and receiving an e-mail at the
same time.
Multi-User, Multitasking Operating System
Multiuser/Multitasking operating system is a powerful operating system that supports
more than one user at a time and can perform more than one task at a time. UNIX is an
example of a multiuser multitasking operating system. In this operating system, all or
most of the computing occurs at the server. The operating system must make sure that the
requirements of the various users are balanced, and that each of the programs they are
using has sufficient and separate resources. In this OS, if one user is affected remainig
other users stay active.
Utility Programs
Utility programs refer to small programs, which provide additional capabilities to the
computer system. These programs are not provided by the main operating system.
They only provide the additional features to the computer system. Utilities can also be
applications such as screensavers, font and icon tools, desktop enhancements, etc. Some
of the functions of utility program are listed below.
Repairing damaged files
Detecting and removing computer viruses
Reorganising files
Compressing files
Translating instructions to display
Some of the major categories of utility software are listed below.
Disk Defragmenter: Defragmentation is the process of consolidating fragmented files on
the user’s hard drive.
New Gateway to Computer Science Book -9 59
Antivirus: Antivirus software is a type of program designed and developed to protect
computers from malware like viruses, computer worms, spyware, etc. The function of
antivirus program is to detect and remove viruses from the computer system.
Disk Cleanup: Disk Cleanup is a computer maintenance utility tool that is included
in the Microsoft Windows operating system and it is designed to free up space on the hard
drive.
File Manager: File manager is a computer program that provides a user interface to
manage the files and folders of a computer system.
Backup Uutility: Data backup software is an application used to create a duplicate copy
of data to safeguard files and recovery them in case they are lost, corrupted or infected by
malware.
Disk Compression: A type of data compression that works by storing compressed
versions of files on the hard disk. A disk compression utility stays between the operating
system and the disk drive.
Device Drivers
A device driver is a software program that enables a specific hardware device to work
with an operating system. The device driver acts as a translator between the I/O devices. A
device driver may be required for internal components, such as video cards , optical media
drives as well as external peripherals, such as printers , monitors, etc.Most of the modern
hardware components are “plug and play,”. It means the devices will work without driver
installation. However, if a hardware device is not recognized by the operating system
itself we need to install the correct drivers so that the device functions properly.
Let’s Review
A real-time operating system must have well-defined, fixed time constraints,
otherwise the system will fail to work.
An operating system that allows a single user to perform just one task at a time
is called single user single tasking operating system.
A single-user, multi-tasking operating system is one that allows a single user to
perform two or more functions at a time.
UNIX is an example of a multiuser multitasking operating system.
Multitasking operating system is a powerful operating system that supports
more than one user at a time.
Utility programs refer to the small programs, which provide additional capabilities
to the computer system.
A device driver is a software program that enables a specific hardware device
to work with a computer’s operating system.
60 New Gateway to Computer Science Book -9
Application Software
Software which is developed to help the user to perform specific tasks is called application
software. Application software consists of instructions that direct a computer system to
perform specific information processing activities for users. A large number of different
application software programs available have different uses in the computer. Application
software uses the capacity of a computer directly for specific tasks and is used to manipulate
text, graphics and numbers.Various examples of application softwares are listed below.
Word processing software
Database programs
Entertainment software
Business software
Educational software
Computer-aided design(CAD) software
Spreadsheet software, etc.
Types of Application Software
Packaged Software: Packaged Software is readymade, error free, advance and standard
software for general work.All word processing, database management, graphics, animation
and web-designing softwares are packaged softwares. This software is equipped with
all essential tools and technology to enhance the user's productivity. Software programs
included in packaged software are available to purchase individually. However, purchasing
the packaged software is cheaper than purchasing each software program separately.
Tailored Software: Tailored software is small software, developed by using high level
language for specific small process. These types of softwares are developed for certain
purpose.This software is also called customized software. Software for payroll for
specific organization, software for specific bank, software for railway reservation, hotel
reservation, etc. are the examples of tailored software. This software is developed for
solving specific problems of specific users or organizations
Introduction to GUI Environments
Most of the modern operating systems are Graphical User Interface (GUI) based. GUI is
a type of user interface that enables the users to interact with the operating system
by means of point-and-click operations. A GUI uses windows, icons, and menus to
carry out commands, such as opening, deleting, and moving files. Many GUI operating
systems are navigated through the use of a mouse; the keyboard can also be utilized
by using keyboard shortcuts or arrow keys. The GUI was first developed by Alan Kay,
Douglas Engelhard, and a group of other researchers in 1981 AD.
New Gateway to Computer Science Book -9 61
Let’s Review
Software which is developed to help the user to perform specific tasks is called
application software.
Application software uses the capacity of a computer directly for specific tasks
and is used to manipulate text, graphics and numbers.
Packaged software is readymade, error free, advance and standard software for
general works.
Tailored software is small software, developed by using high level language
for specific small process.
A GUI uses windows, icons, and menus to carry out commands, such as opening,
deleting, and moving files.
Understanding Windows Desktop
A windows desktop is the first display screen which appears when you load an operating
system. It has various icons like This PC, Recycle bin, Network, Control Panel, Internet
explorer, etc. The details of some default components of windows desktop are explained
below.
Recycle Bin: It temporarily stores deleted files until they are removed from the Recycle
Bin permanently.
Taskbar: It contains the minimized applications items like, documents, or other windows
which can be used to quickly switch from one program to another.
Notification Area: It is an area within the taskbar. It is used to indicate the time, as well as
display icons which may be used to quickly start programs, adjust settings, or determine
the status of a current task.
This PC: When we open this icon, it displays the components of the computer. It displays
disk drive, local hard drive, local CD, DVD, pen drive as well as network drives and
printers.
Network: When we open this icon, it displays all the resources available on the
network. It displays applications, data files, and printers. It also displays the computers in
your work group.
Internet Explorer: It is a default web browser application which is used to search and
browse internet content, web sites, etc.
User: When we open this icon it displays the files and objects which have been stored
within. My Documents is the default user storage folder for many software applications.
62 New Gateway to Computer Science Book -9
What is a windows dialogue box?
A dialog box is a user interface element that is used to communicate and interact between
a user and a software program. It is a movable window on the computer screen which
is seen when a user selects a menu option. There are two types of windows dialogue
box they are application window dialogue box and document windows dialogue box.
The application window dialogue box provides a framework for the whole application.
This can be opened, closed, resized, and moved around the desktop. All application
windows dialogue box are normally contained in the application windows. It also
contains the application menu bar and status bar. The document windows dialogue box
appears inside the application windows. A document window dialogue box is a section
of the screen used to display the contents of a document file on a GUI operating system.
Various components of dialogue box are title bar, status area, icon area, panel area, button
area, tab area, toolbar, menu area, etc.
Mouse Pointer and its Activities
The mouse is the primary input device which is used to interact with objects in windows.
A modern mouse typically has a primary button (left button), a secondary button (right
button), and a mouse wheel between the two. By positioning the pointer and clicking the
primary and secondary buttons on the mouse, users can select objects and perform actions
on them. The given table shows various mouse pointers with their functions.
Shape Name Use
Normal select Used for most objects.
Link select Used for text and graphics links because of their weak af-
Text select fordance.
Used for text to indicate a location between characters.
Precision select Used for graphic and other two-dimensional interaction.
Busy pointer Used to wait for a window to become responsive.
Working in back- Used to point, click, press, or select while a task com-
ground pointer pletes in the background.
New Gateway to Computer Science Book -9 63
Common Pointer Shapes
The following tables describe the common pointer shapes, along with their interactions.
Action Interaction
Pointing Place the pointer to a specific object without clicking any mouse buttons.
Hovering Place the pointer to a specific object without clicking any mouse buttons
and without moving for at least a second.
Clicking Place the pointer to a specific, non-selectable object and press and release a
mouse button without moving.
Selecting Place the pointer to a specific, selectable object and press and release a
mouse button.
Pressing Place the pointer to a specific object and press a mouse button without re-
leasing.
Wheeling Move mouse wheel.
File and Folder Management
File management is organizing and keeping track of files and folders. Windows
allows you to organize folders and files in a file hierarchy, like the way you store
paper documents in a record file. Just as a filing cabinet contains several folders,
each containing a set of related documents and folders together. A file hierarchy
allows you to place files in folders, then place folders in other folders, so that
your files are organized and easier to find. Windows provides you with a main file
management window called Windows Explorer. Windows Explorer provides access
to files, folders, drives, and disks on your local, Home group and network computers.
Working with Windows Explorer
Click the windows explorer button on the taskbar
The Windows Explorer window opens, displaying the contents of the libraries folder.
Windws has four default libraries they are Documents, Music, Pictures, and Videos.
Point to libraries, click the expand indicator next to libraries if necessary to expand
the list, then click documents in the navigation pane under libraries.
The contents of the Documents library folder open in your Windows Explorer
window.
If you want to save your files to a USB drive, make sure the USB drive where you
store your data files is plugged into your computer, then click computer in the
navigation pane.
64 New Gateway to Computer Science Book -9
The computer window opens, displaying the contents of your computer, including
all disk drives, removable storage devices, and network locations.
Click the drive where you store your data files.
The bottom pane of the computer window changes to display details about the
selected drive. If you selected a hard drive, the details pane displays additional
information, including free space and total disk size.
Double-click the drive where you store your data files.
The folders contained on the disk drive open in the computer window. When you
open a disk drive or folder, the address bar adds the new location to the list.
Double-click the folder, then double-click the sub folder.
The files and folders are represented by icons that indicate the application they were
created with.
Double-click the folder.
The folder opens and displays the files that have been created.
Let’s Review
A windows desktop is the first display screen which appears when you load an
operating system.
Taskbar contains the minimized application items like, documents, or other
windows which can be used to quickly switch from one program to another.
Internet Explorer is a default web browser application which is used to search
and browse internet content, web sites, etc.
A dialog box is a user interface element that is used to enable communication and
interaction between a user and a software program.
The application window dialogue box provides a framework for the whole
application. This can be opened, closed, resized, and moved around the desktop.
A document window dialogue box is a section of the screen used to display the
contents of a document file on a GUI operating system.
File management is an organizing and keeping track of files and folders.
Language Processor
A language processor is a type of a computer software program that has the capacity of
translating source code or program code into machine code. Language translator will
take a source program as input and then will convert it into object code so that it can be
understood by the computer. Different types of language processors are explained below.
New Gateway to Computer Science Book -9 65
Compilers
A compiler is a language processor that converts the source program into machine
code. The compiler converts source program in machine code which is called an
object program. Compiler checks and reports syntax errors in the program. A source
program containing an error cannot be compiled. A program written in high-level
language is called source program. The program in machine language is called
object program. The programs are written mostly in high level languages like Java, C++,
and Python. They are called source code. These source codes cannot be executed directly
by the computer and must be converted into machine language to be executed.
Interpreters
The translation of single statement of source program into machine code is done
by language processor and executes it immediately before moving on to the next
line which is called an interpreter. If there is an error in the statement, the interpreter
terminates its translating process at that statement and displays an error message.
The interpreter moves on to the next line for execution only after the removal
of the error. An Interpreter directly executes instructions written in a programming or
scripting language without converting them to an object code or machine code.
Assemblers
The assembler is used to translate the program written in assembly language into machine
code. The source program is an input of assembler that contains assembly language
instructions. The output generated by assembler is the object code or machine code
understood by the computer.
Difference between Compiler and Interpreter
Compiler Interpreter
A compiler is a program which converts Interpreter takes a source program and
the entire source code of a programming runs it line by line, translating each line
language into executable machine code. as it comes to it.
Compiler takes large amount of time to Interpreter takes less amount of time to
analyse the entire source code but the analyse the source code but the overall
overall execution time of the program is execution time of the program is slower.
comparatively faster.
Compiler generates the error message Debugging is easier as it continues
only after scanning the whole program, so translating the program until the error is
debugging is difficult as the error can be found.
present anywhere in the program.
Generates intermediate object code. No intermediate object code is generated.
Examples: C, C++, Java Examples: Python, Perl
66 New Gateway to Computer Science Book -9
Introduction to Open Sources Software
Open source software refers to any program whose source code is made available for
use or modification as per user’s choice. Open source software is usually developed as
a public collaboration and made freely available. Source code is the part of software
that most computer users don’t see. It is the code that computer programmers can
manipulate to change how a piece of software, a “program” or “application” works.
Programmers who have access to a computer program’s source code can improve that
program by adding features to it or fixing parts that don’t always work correctly.The open
source software must meet the following criteria for the user accessible.
The program must be freely distributed.
Source code must be included in the program.
Anyone must be able to modify the source code.
Modified versions of the source code may be redistributed.
Advantages of Using Open Source Software
Open source licensing doesn’t involve copyright restrictions. The main advantages of
software with a publicly available source code are:
Flexibility: The software can be customized to meet specific needs.
Stability: You can use this product for long-term projects because it won’t disappear
from the market or become out-dated.
Security and reliability: Many people with different skill levels may work
on the same software, which may lead to code inconsistency.
Better support: You have more ways of getting technical advice and support: from
a vendor, a consultancy company specializing in this product, or from other users
that are ready to share their experience and knowledge across forums or maiing lists.
Let’s Review
A language processor has the capacity of translating source code or program code
into machine code.
A compiler is a language processor that converts the source program into machine
code.
A program written in high-level language is called source program.
The translation of single statement of source program into machine code is done
by language processor.
The assembler is used to translate the program written in assembly language into
machine code.
Open source software refers to any program whose source code is made
available for use or modification as per user’s choice.
Flexibility, stability, security and reliability are the advantages of using open
source software.
New Gateway to Computer Science Book -9 67
An Introduction to Desktop and Web Apps
Desktop application is a machine dependent program that runs on a personal computer
device such as a desktop, laptop and personal workstations. This application needs to
install separately on each and every computer. It has fewer security risks than the web
application security risk. In this application data are stored in a particular storage location
of computer system.
Web application is a machine independent which is complex and a bit more different
than desktop application. In a web application, the application is loaded on the server
and lots of computers are connected with the server whose location is unknown.
In this application, user can use different applications without installing anything on the
personal computer. In this application data are remotely stored on the main server and
application can be accessed from any personal computers using any web browser.
There are various categories of apps available for the various users according to their
requirement. Some of the popular categories of apps are Gaming apps, Business apps,
Education apps, Life style apps, Utility apps, Entertainment apps, Travel apps, etc. Let's
discuss some types of apps below.
Mobile Apps
Mobile applications are also known as mobile apps. They are software programs
developed for mobile devices such as smart phones and tablets. Some of the devices come
preloaded with some mobile apps of their manufacturers or the mobile service providers
with which they are associated. Many more apps are available through device-specific
app stores. Apps are generally small, individual software units with limited function.
The use of apps software was popularized by Apple Inc. and its App Store, which offers
thousands of applications for the iPhone, iPad and iPod Touch. A mobile application also
may be known as an app, web app, online app, iPhone app or smart phone app. Some
types of mobile apps are listed below.
Native Apps
Native apps are developed for a single mobile operating system therefore they are
“native” for a particular platform or device. App built for systems like iOS, Android,
Windows phone, Symbian, Blackberry cannot be used on a platform other than their own.
In other words, you won’t be able to use Android app on iPhone.
68 New Gateway to Computer Science Book -9
Hybrid Apps
Hybrid apps are built using multi-platform web technologies such as HTML5, CSS
and Javascript. Hybrid multi-platform apps are fast and are easy to develop. Hybrid
applications lack performance, speed and overall optimization in comparison to native
apps. There are also some certain design issues due to app inability to look in exactly
same way on two or more platforms.
Web Apps
Web apps are software applications that behave similar to native applications. Web apps
use a browser to run and are usually written in HTML5, Java Script or CSS. These apps
redirect a user to URL and offer “install” option by simply creating a bookmark to their
page. Web applications require minimum of device memory. As all personal databases
are saved on a server, users can get access from any device whenever there is internet
connection.
Let’s Review
Desktop application is a machine dependent program that runs on a personal
computer device such as a desktop, laptop and personal workstations.
Web application is a independent machine which is more complex and a bit
different than desktop application.
There are various categories of apps available for various users according to their
requirement. Some of the popular categories of apps are Gaming apps, Business
apps, Education apps, Lifestyle apps, Utility apps, Entertainment apps, Travel
apps, etc.
Mobile applications are also known as mobile apps.
They are built using multi-platform web technologies such as HTML5, CSS and
Javascript.
Expand your knowledge
Android Inc was founded in Palo Alto, california in october 2003 AD. by
Andy Rubin, Rich Miner, Nick Sears and Chris White.
In 1979 AD, the version of word processors called wordstar was developed.
Early operating system and software were written in assembly language.
C++ was the first used in 1980 AD. for system programming.
Ubuntu is a fast, easy to use and free operating system that can be used on
desktop, laptop and notebook computers.
New Gateway to Computer Science Book -9 69
Assignment
1. Select the correct answer from the given options.
a. Which of the following is a related to computer software?
i. Device Driver ii. Motherboard iii. CPU iv. Hard Disk
b. Which of the following is a system software?
i. Windows ii. Office iii. Database iv. Graphics
c. Which of the following is an operating system?
i. Android ii. iOS iii. Windows iv. All of them
d. Which of the following function refers to the management of memory?
i. Interface ii. Memory management iii File management iv. All of them
e. Which of the following provides an interface between an user and a machine?
i. Office package ii. Graphics package iii. Operating system iv. All of them
f. Which of the following is an utility program?
i. Antivirus ii. File manager iii. Backup utility iv. All of them
g. Which of the following icon stores the deleted items?
i. My network ii. My computer iii. Recycle bin iv. My document
h. Which of the following is an example of compiler?
i. C ++ ii. Python iii. Perl iv. None of them
2. Fill in the blanks with suitable words.
a. ……………………….. is the collections of program and other associated
documents that helps to accomplish a specific task.
b. …………………. provides services that include process management, virtual
memory, file management, and the user interface.
c. An operating system that allows a single user to perform just one task at a time is
called ………………………… operating system.
d. ……………………. is an example of a multitasking operating system.
e. ……………………………. uses the capacity of a computer directly for specific
tasks and is used to manipulate text, graphics and numbers.
f. …………………… software is small software, developed by using high level
language for specific small process.
g. A ……………………. uses windows, icons, and menus to carry out commands,
such as opening, deleting, and moving files.
h. ………………… contains the minimized application items like, documents, or
other windows which can be used to quickly switch from one program to another.
i. A………………… is a user interface element that is used to enable communication
and interaction between a user and a software program.
j. A document ………box is a section of the screen used to display the contents of
a document file on a graphical user interface (GUI) operating system.
70 New Gateway to Computer Science Book -9
3. State whether the given statements are true or false
a. Systems software is a set of instructions that serves mainly as an intermediary
between computer hardware and application programs.
b. Process management, file management, memory management, etc. are the
functions of an operating system.
c. A device driver provides an interface between a user and a machine.
d. A single-user, multi-tasking operating system is one that allows a single user to
perform two or more functions at a time.
e. Single tasking operating system is a powerful operating system that supports
more than one user at a time.
f. Software which is developed to help the user to perform specific tasks is called
application software.
g. OS is readymade, error free, advance and standard software for general works.
h. Open source refers to any program whose source code is made available for use
or modification as per users the requirement.
i. A windows desktop is the first display screen which appears when you loaded an
operating system.
j. Recycle bin is used to organizing and keeping track of files and folders.
4. Write appropriate technical terms for the followings.
a. The software that are used to manage the OS with the co-ordination of computer
hardware system and their resources.
b. A computer system that helps to control and coordinate overall activities of the
computer system.
c. An operating system that allows a single user to perform just one task at a time.
d. The small programs, which provide additional capabilities to the computer system.
e. Antivirus software is a type of program designed and developed to protect
computers from malware.
f. A software program that enables a specific hardware device to work with a
computer's operating system.
g. It is a default web browser application which is used to search for and browse
internet content, web sites, etc.
h. The programs are written mostly in high level languages like Java, C++, and
Python etc.
i. A machine dependent program that runs on a personal computer device such as a
desktop, laptop and personal workstations.
j. These applications are also known as mobile apps that are the software programs
developed for mobile devices such as smartphones and tablets.
New Gateway to Computer Science Book -9 71
5. Write the full form of the followings.
GUI , CLI, OS, PDA
6. Match the following.
Windows OS Language translator
Compiler Operating System
Antivirus Desktop icon
Recycle bin Application program
MS-Word Utility software
7. Answer the following questions.
a. What is a computer software? Write its tasks.
b. Define system software with its types.
c. What is an operating system? Name any three popular operating systems.
d. What are the major functions of an operating system?
e. What are the types of operating system? Define each in one sentence.
f. What are utility programs? Write its functions.
g. Name any two utility programs and define them.
h. What is a device driver? For what it is required?
i. Define application software with examples.
j. What are the types of application softwares? Define them in short.
k. Name the items available in windows desktop and explain the functions of any
three icons.
l. What is a windows dialogue box? What are the types of the windows dialogue
box?
m. Name any three mouse pointers and write their activities.
n. What do you mean by file and folder management? Why is it important in computer
system.
o. What is a language processor? Write down the types of the language processor.
p. Write down the differences between a compiler and an interpreter.
q. What is an open source software? What are the advantages of using an open source
software.
r. Define desktop application and web application.
s. Define mobile apps and hybrid apps.
Project Work
Take a short interview with your parents and relatives and prepare a field report about
what type of mobile phone or laptops or other devices they are using, what types of OS
the devices install. Also make a list of apps that they have used in their smart phones.
72 New Gateway to Computer Science Book -9
Working with Graphics
Unit
2
This unit covers the following topics:
Lesson 6: Introduction to Computer Graphics
New Gateway to Computer Science Book -9 73
Lesson
6 Introduction to Computer Graphics
Inside the Lesson
Introduction to the graphics
Uses of graphics software
Different types of graphics format
Working with photoshop CS6
Starting photoshop
Understanding photoshop tools
Creating , opeaning and saving image
understanding graphics format
Working with image size and resolution
Working with photoshop tools
Changing the size of image
Cropping the image
Working with text tool
The computer is an information processing machine. It is a tool for storing and
manipulating data. There are many ways to communicate the processed information to
the user. The computer graphics is one of the most effective and commonly used ways
to communicate the processed information to the user. It displays the information in the
form of graphics objects such as pictures, charts, graphs and diagrams instead of simple
text. Thus, we can say that computer graphics makes data possible to express in pictorial
form. The picture or graphic object may be an engineering drawing, business graph,
architectural structures, a single frame from an animated movie, or a machine parts. The
term “computer graphics” refers to anything involved in the creation or manipulation of
images on computer, including animated images.
Computer graphics is an art of drawing pictures on computer screens with the help of
various computer graphics programs. It involves computations, creation, and manipulation
of data. In other words, we can say that computer graphics is a rendering tool for the
generation and manipulation of images.
74 New Gateway to Computer Science Book -9
Uses of Graphics Software Let’s Review
Graphic designing software is used by Some abbreviations:
graphic designers to create images in JPEG (or JPG) - Joint Photographic
different ways to edit images, to create Experts Group
video, audio, etc.Graphic software helps PNG - Portable Network Graphics
users to give visual effects in all form. GIF - Graphics Interchange Format
There are two types of graphic designing TIFF - Tagged Image File
softwares. One is pixel and another is vector PSD - Photoshop Document
based graphic software. There are different PDF - Portable Document Format
types of graphics softwares used by graphics EPS - Encapsulated Postscript
designer on the basis of requirements. Some AID - Adobe Illustrator Document
of the graphics software are listed below. INDD - Adobe Indesign Document
Diagram designing software RAW - Raw Image Formats
Photoshop
Web designing software
Image viewer and management software
InDesign
Different Graphics Format
There are various types of graphics file formats. Each type stores graphics data in a
different way. Raster, vector and metafile formats are most commonly used file formats.
Let’s discus some major file formats.
Raster Graphics (Bitmap Graphics) Format
Bitmap graphics are also called raster files; that contain an exact pixel-by-pixel map of
an image. Bitmap formats are used to store bitmap data. Files of this type are particularly
well-suited for the storage of real-world images such as photographs and video images.
A rendering application can subsequently reconstruct this image on the display surface of
an output device. Microsoft BMP, PCX, TIFF, and TGA are examples of commonly used
bitmap formats.
Vector Graphics Format
Vector graphics file formats are particularly useful for storing line-based elements, such
as lines and polygons, or those that can be decomposed into simple geometric objects,
such as text. Vector files contain mathematical descriptions of image elements, rather than
New Gateway to Computer Science Book -9 75
pixel values. A rendering application uses these mathematical descriptions of graphical
shapes to construct a final image. In general, vector files are structurally simpler than
most bitmap files and are typically organized as data streams.
Metafile Graphics Format
Metafiles can contain both bitmap and vector data in a single file. The simplest metafiles
resemble vector format files that may be used to define vector data elements, but they may
also store a bitmap representation of an image. Metafiles are frequently used to transport
bitmap or vector data between hardware platforms, or to move image data between
software platforms. WPG, Macintosh PICT, and CGM are examples of commonly used
metafile formats.
Let’s Review
The computer graphics is one of the most effective and commonly used ways to
communicate the processed information to the user.
Computer graphics is an art of drawing pictures on computer screens with the
help of various computer graphics programs.
Graphic designing software are used by graphic designers to create images in
different ways, to edit images, to create video, audio, images, etc.
There are various different types of graphics file formats. Each type stores
graphics data in a different way.
Bitmap graphics are also called raster files.
Vector graphics file formats are particularly useful for storing line-based
elements, such as lines and polygons.
Metafiles can contain both bitmap and vector data in a single file.
Working with Photoshop CC
Adobe Photoshop is an image editing software which allows users to create
and edit raster images in multiple layers. It has a various editing tools.
It was created by Thomas and John Knoll in 1988 AD. The default file extension for
a work in progress is called a PSD (Photoshop Document). A PSD file has a
maximum of 30,000 pixels for width and height and a file length limit of 2
gigabytes. Another type of Photoshop file is Photoshop Big (.PSB ), it is a large document
format and extends the PSD’s maximum height and width limit to 300,000 pixels and
76 New Gateway to Computer Science Book -9
also extends the length limit to around 4 Exabyte. The first version of Photoshop 1.0 was
released on February 19, 1990 AD. Here we are going to discuss about one of the best
versions of Photoshop CC.
Starting Photoshop in Windows 8
Press the windows key and type Adobe Photoshop CC in search box and press
enter key to open the Photoshop CC.
The Photoshop windows will display as below.
New Gateway to Computer Science Book -9 77
Tools of Photoshop
Photoshop has various tools for the picture creating and
editing. The tool always appears at the left most side of the
window. Let’s identify the tools of Photoshop.
1: Rectangular marquee tool: Make the image square or
rectangular
2: Move tool: Move the picture or image.
3: Lasso tool: Free selection with the help of mouse
4: Quick selection tool: Quick selection from the brush tool
5: Crop tool: Crop the image in required size.
6: Eye dropper tool: Select the colour from the image.
7: Spot healing brush tool: Remove the spot from the image.
8: Brush tool: Paint the image.
9: Clone stamp tool: Make clone and duplicate in the
selected area.
10: History brush tool: Apply synapse paint.
11: Eraser tool: Remove any part of the image.
12: Gradient tool: Fill gradient from one colour to another colour.
13: Blur tool: Make image dim by deducting the pixel contrast.
14: Dodge tool: Bring lightness on the image.
15: Pen tool: Edit point location and draw any type of shape.
16: Type / Text tool: Type the text, symbols or characters.
17: Path selection tool: Select an export of any part of image to other application.
18: Rectangle tool: Draw rectangle shape.
19: Hand tool: Move the image to the desired area.
20: Zoom tool:View the image in larger or smaller size.
21: Toggle tool: Set the opposite colour.
22: Foreground colour tool: To apply the foreground colour
23: Background colour tool: To apply the background colour
78 New Gateway to Computer Science Book -9
Creating a New Image
Click on File menu and select New… from the
options.
In the New dialogue box, Type a Name of the
image.
Change the document size (width, Height,
Resolution, Colour Mode, etc.) if required as
shown in the given windows.
Finally, click on OK to create a new working screen.
Opening a N0ew Image
Click on File menu and select Open…
from the options.
The open dialogue box will appear.
Select the location from Look in: where
you have saved your images.
Choose the required image and click on Open button to display the image. 79
New Gateway to Computer Science Book -9
Saving a Iew Image
Click on File menu and select Save from the options.
A save as dialogue box will appear as below.
Select the location where you want to store your picture from Save in: options.
Type required file name in File name box and select the required file Format
that you want.
Finally click on Save button to save your image.
Understanding Files (graphics) Formats
While Photoshop can be used to create files for all sorts of media, the three most common
uses for image files are web, print, and video production. Following is a list of the most
common formats and how they are used.
80 New Gateway to Computer Science Book -9
Web Production Formats
JPEG This is a common format for digital camera photographs and the
(Joint Photographic primary format for full-colour images shared on the web. JPEG
Experts Group) images use lossy compression, which degrades the quality of
images and discards colour and pixel data.
GIF (Graphic GIF files are used to display limited colour graphics on the Web.
Interchange It is a compressed format that reduces the file size of images, but
Format) it only supports a limited number of colours.
PNG PNG (Portable Network Graphics) is a newer image format that
(Portable provides a combination of many features of both JPEG and GIF.
Network The PNG format allows for use of millions of colorus as well as
Graphics) providing the ability to have transparent backgrounds.
Print Production Formats
PSD The Photoshop Format (PSD) is the default file format. Files saved
(Photoshop as PSD can be used in other Adobe applications, such as Adobe
document) Illustrator, Adobe InDesign, Adobe Premiere, and others.
TIFF or TIF TIFF is a common bitmap image format. Most image-editing software
(Tagged Image and page-layout applications support TIFF images up to 2GB in file
File Format) size. TIFF supports most colour modes and can save images with
alpha channels.
EPS EPS files may contain both vector and bitmap data. Because it is
(Encapsulated a common file format used in print production. Some software
PostScript) applications cannot preview the high-resolution information
contained within an EPS file, so Photoshop allows you to save a
special preview file for use with these programs, using either the EPS
TIFF or EPS PICT option.
Photoshop Photoshop PDF files are extremely versatile, as they may contain
PDF bitmap and vector data. Images saved in the Photoshop PDF format
can maintain the editing capabilities of most Photoshop features,
such as vector objects, text, and layers, and most colour spaces are
supported. These files can be opened by users with the free Adobe
Reader software.
New Gateway to Computer Science Book -9 81
Understanding Image Size and Resolution of Graphics
Pixel: A pixel is the smallest unit of a digital image or graphic that can be
displayed and represented on a digital display device. A pixel is also known as a picture
element. It is the basic logical unit in digital graphics. Pixels are combined to form a
complete image, video, text or any visible thing on a computer display. It is represented
by a dot or square on a computer monitor display screen. Depending on the graphics card
and display monitor, the quantity, size and colour combination of pixels vary and are
measured in terms of display resolution.
Resolution: Resolution is the sharpness and clarity of an image or picture. It is used to
measure the quality of monitors, printers, digital images and various other hardware and
software technologies. The resolution of monitor is measured by the number of pixels.
Printers also have a measure of resolution called DPI (dots per inch).
Different resolutions for common widescreen monitors
Monitor size Resolution
19-inch 1680 x 1050
21-inch 1920 x 1080
23-inch 1920 x 1080 to 2560 x 1440
27-inch 2560 x 1440 to 3840 x 2160
Different resolutions for common ultra wide resolutions monitors
Monitor size Resolution
25-inch 2560 x 1080
29-inch 2560 x 1080
34-inch 2560 x 1080 to 3440 x 1440,
Resampling: Resampling is the process of changing the amount of image data as you
change either the pixel dimensions or the resolution of an image. When you decrease
the number of pixels, information is deleted from the image. When you resample up or
increase the number of pixels, new pixels are added.
Resizing: When you resize an image and do not resample it, you change the image’s size
without changing the amount of data in that image. Resizing without resampling changes
the image’s physical size without changing the pixel dimensions in the image. No data is
added to or removed from the image.
82 New Gateway to Computer Science Book -9
File size: The file size of an image is the digital size of the image file, measured in
kilobytes (K), megabytes (MB), or gigabytes (GB). File size is proportional to the pixel
dimensions of the image. Images with more pixels may produce more detail at a given
printed size, but they require more disk space to store and may be slower to edit and print.
Let’s Review
Adobe Photoshop is an image editing software which allows the users to create
and edit raster images in multiple layers.
Photoshop has various tools for creating and editing picture.
JPEG is a common format for digital camera photographs and the primary format
for full-colour images shared on the web.
GIF files are used to display limited colour graphics on the Web.
The PNG format allows for use of millions of colorus as well as provides the
ability to have transparent backgrounds.
The Photoshop format (PSD) is the default file format.
TIFF supports most colour modes and can save images with alpha channels.
Photoshop PDF files can be opened by users with the free Adobe Reader software.
A pixel is the smallest unit of a digital image or graphic that can be displayed and
represented on a digital display device.
A pixel is also known as a picture element.
Resolution is the sharpness and clarity of an image or picture.
Resampling is the process of changing the amount of image data as you change
either the pixel dimensions or the resolution of an image.
Pixel Dimensions and Printed Image Resolution
Pixel dimensions measure the total number Same image at 72 ppi and 300 ppi;
of pixels along an image’s width and height. inset zoom 200%
Resolution is the fineness of detail in a
bitmap image and is measured in pixels per
inch (ppi). The more pixels per inch, the
greater the resolution. Generally, an image
with a higher resolution produces a better
printed image quality.
Unless an image is resampled the amount of
image data remains constant as you change
either the print dimensions or resolution.
For example, if you change the resolution of
New Gateway to Computer Science Book -9 83
an image, its width and height change accordingly to maintain the same amount of image
data.
In Photoshop, you can see the relationship between image size and resolution with the
help of the given steps.
In the Image Size dialog box choose Image and move on Image Size options.
Deselect Resample Image (because you don’t want to change the amount of image
data in your photo).
Change width, height, or resolution as required.
As you change one value, the other two values change accordingly with the Resample
Image option selected, you can change the resolution, width, and height of the image
as required.
In the above dialouge box, A. Original dimensions and resolution B. Decreasing the
resolution without changing pixel dimensions (no resampling) C. Decreasing the
resolution at same document size decreases pixel dimensions (resampling).
84 New Gateway to Computer Science Book -9
Understanding Photoshop Tools
When we start Photoshop, we can see the tools panel. The tools panel appears at the left of
the screen. Some tools in the tools panel have options that appear in the context-sensitive
options bar. You can expand some tools to show hidden tools. A small triangle at the lower
right of the tool icon signals the presence of hidden tools.
Move and selection tools
Move Tool * ( V )
The Move Tool is used to move layers, selections and guides within a Photoshop
document. Enable "Auto-Select" to automatically select the layer or group you
click on.
Artboard Tool ( V )
The Artboard Tool allows you to easily design multiple web or UX (User
Experience) layouts for different devices or screen sizes.
Rectangular Marquee Tool * ( M )
The Rectangular Marquee Tool draws rectangular selection outlines. Press and
hold Shift as you drag to draw a square selection.
Elliptical Marquee Tool ( M )
The Elliptical Marquee Tool draws elliptical selection outlines. Press and hold
Shift to draw a selection in a perfect circle.
Single Row Marquee Tool
The Single Row Marquee Tool in Photoshop selects a single row of pixels in the
image from left to right.
Single Column Marquee Tool
Single Column Marquee Tool is used to select a single column of pixels from
top to bottom.
Lasso Tool * ( L )
With the Lasso Tool, you can draw a freeform selection outline around an object.
New Gateway to Computer Science Book -9 85
Polygonal Lasso Tool ( L )
You can click around an object with the Polygonal Lasso Tool to surround it
with a polygonal, straight-edged selection outline.
Magnetic Lasso Tool ( L )
The Magnetic Lasso Tool snaps the selection outline to the edges of the object
as you move your mouse cursor around it.
Quick Selection Tool * ( W )
The Quick Selection Tool lets you easily select an object simply by painting
over it with a brush.
Magic Wand Tool ( W )
The Magic Wand Tool selects areas of similar color with a single click. The
"Tolerance" value in the Options Bar sets the range of colors that will be selected.
Crop And Slice Tools
Crop Tool * ( C )
You can use the Crop Tool in Photoshop to crop an image and remove unwanted
areas.
Perspective Crop Tool ( C )
You can use the Perspective Crop Tool to crop an image and fix common
distortion or perspective problems.
Slice Tool ( C )
The Slice Tool divides an image or layout into smaller sections which can be
exported and optimized separately.
Slice Select Tool ( C )
The Slice Select Tool is used to select individual slices created with the Slice
Tool.
Measurement Tools
Eyedropper Tool * ( I )
The Eyedropper Tool samples colours in an image. Increase "Sample Size" in
the Options Bar for a better representation of the sampled area's colour.
86 New Gateway to Computer Science Book -9
3D Material Eyedropper Tool ( I )
You can use the 3D Material Eyedropper Tool to sample material from a 3D
model in Photoshop.
Colour Sampler Tool ( I )
The Color Sampler Tool displays colour values for the selected area in an image.
Ruler Tool ( I )
The Ruler Tool measures distances, locations and angles of the image.
Note Tool ( I )
The Note Tool allows you to attach text-based notes to your Photoshop document,
either for yourself or for others working on the same project.
Count Tool ( I )
You can use the Count Tool to manually count the number of objects in an
image, or to have Photoshop automatically count multiple selected areas in the
image.
Retouching And Painting Tools
Spot Healing Brush Tool * ( J )
The Spot Healing Brush Tool in Photoshop quickly removes blemishes and
other minor problem areas in an image. Use a brush size slightly larger than the
blemish for the best result.
Healing Brush Tool ( J )
The Healing Brush Tool lets you repair larger problem areas in an image by
painting over them.
Patch Tool ( J )
With the Patch Tool, you can draw a freeform selection outline around a
problem area. Then repair it by dragging the selection outline over an area of
good texture.
Content-Aware Move Tool ( J )
You can use the Content-Aware Move Tool to select and move the part of an
image to a different area.
New Gateway to Computer Science Book -9 87
Red Eye Tool ( J )
The Red Eye Tool removes common red eye problems in a photo resulting from
camera flash.
Brush Tool * ( B )
The Brush Tool is Photoshop's primary painting tool. You can use it to paint
brush strokes on a layer or on a layer mask.
Pencil Tool ( B )
The Pencil Tool is another tool of Photoshop's painting. But while the Brush
Tool can paint soft-edge brush strokes, the Pencil Tool always paints with hard
edges.
Colour Replacement Tool ( B )
You can use the Colour Replacement Tool in Photoshop to easily replace the
colour of an object with a different colour.
Mixer Brush Tool ( B )
The Mixer Brush Tool can simulate elements of real painting such as mixing
and combining colours, and paint wetness.
Clone Stamp Tool * ( S )
The Clone Stamp Tool is the most basic tool of Photoshop. It samples pixels
from one area of the image and paints them over pixels in another area.
Pattern Stamp Tool ( S )
You can use the Pattern Stamp Tool to paint a pattern over the image.
History Brush Tool * ( Y )
The History Brush Tool paints a snapshot from an earlier step into the current
version of the image.
Art History Brush Tool ( Y )
The Art History Brush Tool also paints a snapshot from an earlier history state
into the image, but does so using stylized brush strokes.
Eraser Tool * ( E )
The Eraser Tool permanently erases pixels on a layer. It can also be used to
paint in a previous history state.
88 New Gateway to Computer Science Book -9
Background Eraser Tool ( E )
The Background Eraser Tool erases areas of similar colour in an image by
painting over them.
Magic Eraser Tool ( E )
The Magic Eraser Tool is similar to the Magic Wand Tool. It selects areas of
similar colour with a single click. But the Magic Eraser Tool then permanently
deletes those areas.
Gradient Tool * ( G )
Gradient Tool is used to draw gradual blends between multiple colours. The
Gradient Editor lets you create and customize your own gradients.
Paint Bucket Tool ( G )
The Paint Bucket Tool fills an area of similar colour with your Foreground
colour or a pattern.
3D Material Drop Tool ( G )
This tool is used in 3D modelling, the 3D Material Drop Tool lets you sample a
material from one area and then drop it into another area of your model, mesh
or 3D layer.
Blur Tool *
The Blur Tool blurs and softens areas you paint over with the tool.
Sharpen Tool
The Sharpen Tool sharpens areas you paint over.
Smudge Tool
The Smudge Tool smudges and smears the area you paint over. It can also be
used to create a finger painting effect.
Dodge Tool * ( O )
You can use Dodge Tool to Paint over an areas in the image and lighten it.
Burn Tool ( O )
The Burn Tool will darken the areas you paint over.
New Gateway to Computer Science Book -9 89
Sponge Tool ( O )
Paint over areas with the Sponge Tool to increase or decrease colour saturation.
Drawing And Type Tools
Pen Tool * ( P )
The Pen Tool allows you to draw extremely precise paths, vector shapes or
selections.
Freeform Pen Tool ( P )
The Freeform Pen Tool allows you to draw freehand paths or shapes. Anchor
points are automatically added to the path as you draw.
Add Anchor Point Tool
You can use the Add Anchor Point Tool to add additional anchor points along
a path.
Horizontal Type Tool * ( T )
It is a Type Tool in Photoshop, you can use the Horizontal Type Tool to add
standard type to your document.
Vertical Type Tool ( T )
The Vertical Type Tool adds the text vertically from top to bottom.
Vertical Type Mask Tool ( T )
Rather than adding editable text to your document, the Vertical Type Mask Tool
creates a selection outline in the shape of vertical type.
Horizontal Type Mask Tool ( T )
Like the Vertical Mask Type Tool, the Horizontal Type Mask Tool creates a
selection outline in the shape of type. However, the type is added horizontally
rather than vertically.
Path Selection Tool * ( A )
You can use the Path Selection Tool to select and move to an entire path at once.
Direct Selection Tool ( A )
You can use the Direct Selection Tool to select and move to an individual path
segment, anchor point or direction handle.
90 New Gateway to Computer Science Book -9
Rectangle Tool * ( U )
The Rectangle Tool draws rectangular vector shapes, paths or pixel shapes.
Press and hold Shift as you drag to force the shape into a perfect square.
Rounded Rectangle Tool ( U )
The Rounded Rectangle Tool is similar to the standard Rectangle Tool but
draws the shapes with rounded corners. Press and hold Shift to draw a square
with rounded corners.
Ellipse Tool ( U )
The Ellipse Tool draws elliptical vector shapes, paths or pixel shapes. Press and
hold Shift as you drag to draw a perfect circle.
Polygon Tool ( U )
The Polygon Tool draws polygonal, straight-edged vector shapes, paths or pixel
shapes. Use the "Sides" option in the Options Bar to set the number of sides.
Line Tool ( U )
The Line Tool draws straight lines, either as shapes or paths. The "Weight"
option in the Options Bar controls the width of the line.
Custom Shape Tool ( U )
Custom Shape Tool helps to select and draw custom shapes.
Navigation Tools
Hand Tool * ( H )
The Hand Tool helps to click and drag an image around on the screen to
view different areas when zoomed in.
Rotate View Tool ( R )
You can use the Rotate View Tool in Photoshop to rotate the canvas, so you can
view and edit the image from different angles.
Zoom Tool * ( Z )
You can click on the image with the Zoom Tool to zoom in on a specific area.
Press and hold Alt and click the Zoom Tool to zoom out.
New Gateway to Computer Science Book -9 91
Let’s Review
Pixel dimensions measure the total number of pixels along an image’s width and
height.
The Move Tool is used to move layers, selections and guides within a Photoshop
document.
The Single Row Marquee Tool in Photoshop selects a single row of pixels in the
image from left to right.
The Slice Tool divides an image or layout into smaller sections which can be
exported and optimized separately.
The Colour Sampler Tool displays colour values for the selected area in an image.
The Note Tool allows you to attach text-based notes to your Photoshop document.
The Red Eye Tool removes common red eye problems in a photo resulting from
camera flash.
The Background Eraser Tool erases areas of similar colour in an image by painting
over them.
The Smudge Tool in Photoshop smudges and smears the areas you paint over.
The Freeform Pen Tool allows you to draw freehand paths or shapes.
The Polygon Tool draws polygonal, straight-edged vector shapes, paths or pixel
shapes.
Working with Photoshop Tools
Lasso tool
This tool is used for free selection on the image as required.
Open the required image.
Click on the lasso tool from the tool box.
Click on the picture and drag the mouse to select the
required area.
Eraser Tool
Eraser tool is used to remove certain area or part of the
image.
Open the required image.
Click on the eraser tool from the tool box.
Click and drag the mouse to erase the required portion of
the image.
92 New Gateway to Computer Science Book -9
Gradient Tool
This tool is used to fill colours horizontally. We can use this tool to create banners.
Open the required image.
Select the part of the image.
Click on the gradient tool from the tool box.
Drag the mouse across the image.
Move towards left or right or as your desired location to
apply it.
Blur Tool
You can also blur portions of your image to emphasize and focus
on a particular element. It is used to reduce the extra pixel contrast and make the image
dim.
Open the required image.
Click on the blur tool from the tool box.
Choose the required brush from the present picker.
Drag the mouse pointer over the part of the picture and
release the mouse.
Zoom Tool
This tool is used to enlarge the size of the image. This tool is
like a magnifying glass.
Open the required image.
Click on the zoom tool from the tool box.
Press CTRL + (+) for zoom in [Larger View] and CTRL + (-) for zoom out
[smaller view] of the image.
New Gateway to Computer Science Book -9 93
Hand Tool
This tool is used to move the image horizontally or vertically on
the screen.
Open the required image.
Click on the hand tool from the tool box.
Click on image then drag it as required.
Drag the mouse pointer over the part of the picture and
release the mouse.
Clone Stamp Tool
Clone stamp tool allows you to copy one area of image onto another area of image.
Open an image.
Click on clone tool from the tool box.
Keep on pressing ALT key and click on the area of the
image.
Click on the new area of the image to apply the effect.
Dodge Tool
This tool is used to apply more lightness on the image. We can use the given steps to apply
this.
Open the image in which you want to apply the
effects.
Click on the Dodge tool from the tool box.
Click on image then drag it as required
Spot Healing Brush Tool
The spot healing brush is the default healing tool in
Photoshop. It can be used to clone areas from an image and blend the pixels from the
sampled area seamlessly with the target area.
Select the Spot Healing Brush tool from the toolbox.
Choose a brush size from the option bar.
Choose blending mode from the mode menu.
Choose Replace to preserve noise, film grain and texture at the edges of the
brush stroke.
Click on the area where you want to fix, or click and drag over a larger area.
94 New Gateway to Computer Science Book -9
Magic Wand Tool
This tool is used to select a larger area of image having similar colour, pixel and groups
together.
Open the required image.
Select the Magic Wand tool . (If the tool isn’t visible,
access it by holding down the Quick Selection tool .)
Click on the area of an image to select.
Changing the Size of an Image
We can reduce the size of an image in Photoshop. To change
the image size in Adobe Photoshop let’s follow the given steps.
Click on Image Size option from the Image menu.
Activate the check-box Constrain Proportions to keep the
ratio of the image dimensions.
Make sure that the check-box Resample Image is activated.
Select the method of interpolation: Nearest Neighbour,
Bilinear or Bicubic.
In the Pixel Dimensions group select the unit measure and
enter new values for the parameters Width and Height as
given below.
Finally click on OK button to apply the image size. 95
New Gateway to Computer Science Book -9
Changing Image Resolution
Click on image menu and choose
Image Size.(Resolution in this dialogue
box means the number of image pixels
that will be assigned to each inch when the
image is printed.)
Leave width and height set to inches for
printing.
Deselect Resample to preserve the original
number of image pixels.
In the Resolution field, set the number of pixels per inch to 300 for printing.
This changes the number of inches in the width and height fields.
Click OK.
Changing Canvas Size
Click on Image menu and select Canvas Size
option.
To add a canvas, enter the amount of width and
height to add. Measure width and height in pixels
for online use or in inches for print.
Select Relative, and then select an anchor point
in the canvas diagram. The arrows point to the
sides where the canvas will be added.
Finally click OK to apply.
Cropping the Image
Open an image in which you want to apply the effects.
Select the Crop tool in the Tools panel. A crop border
appears.
Drag any edge or corner to adjust the size and shape of
the crop border.
Drag inside the crop border to place the image inside
the crop border.
Drag outside a corner of the crop border to rotate or straighten.
Click the check mark in the options bar or press Enter to complete the crop.
96 New Gateway to Computer Science Book -9
Working with Text Tool
The type tool allows you to add text to your file. You can use text on a variety of projects,
such as adding it to your images to create a poster, card, or invitation. You can also
customize the text as required.
Using Type Tool
Select the Type tool from the Tools panel. You can also press the
letter T key on your keyboard to access the Type tool at any time.
In the Control panel near the top of the screen, choose the desired
font and text size.
Click the Text Colour picker, then choose the desired colour from the dialog box.
Click and drag anywhere in the document window to create a text box.
New Gateway to Computer Science Book -9 97
A new text layer will be added to your document. You can start typing to add
text to the layer.
If you want to add a lot of texts to your document, you can work with multiple text layers
which will give you more control over the appearance of your text.
Let’s Review
Cropping the picture is a way of removing portions of a photo or image to create
focus or strengthen the composition.
Lasso tool is used for free selection on the image as required.
Eraser tool is used to remove certain areas or parts of the image.
Gradient tool is used to fill colours horizontally. We can use this tool to create
banners.
You can also blur portions of your image to emphasize and focus on a particular
element.
Zoom tool is used to enlarge the size of the image.
Hand tool is used to move the image horizontally or vertically on the screen.
We can use text tool to type the text, symbols, characters and sentence on selected
area.
Clone stamp tool allows you to copy one area of image onto another area of
image.
Dodge tool is used to apply more lightness on the image.
The spot healing brush tool can be used to clone areas from an image and
blend the pixels from the sampled area seamlessly with the target area.
Magic Wand tool is used to select a larger area of image having similar colour,
pixel and groups together.
The type tool allows you to add text to your image.
98 New Gateway to Computer Science Book -9
Expand your knowledge
In 1950 AD Ben Laposky created the first graphic images, an oscilloscope,
generated by the electronic analog machine.
The Whirlwind computer at the Massachusetts Institute of Technology (MIT)
has the first computer with a video display or real time data.
The first light pen was created around 1955 AD. as a part of Whirlwind project
at MIT.
The first vedio game, space war, ran using an oscilloscope as a display.
The A pple II was the graphics personal computer.
Assignment
1. Select the correct answer from the given options.
a. Which of the following is the example of bitmap image format?
i. BMP ii. PCX iii. TIFF iv. All of them
b. Which file can contain both bitmap and vector data in a single file?
i. Metafile ii. Raster iii. Vector iv. None of them
c. What is the default file extension of Photoshop document?
i. .PDS ii. .PSD iii. .PMD iv. .PMK
d. Which Photoshop tool brings lightness on the image?
i. Pen tool ii. Eraser tool iii. Dodge tool iv. Toggle tool
e. Which of the following is the smallest unit of a digital graphics that can be
displayed and represented on a digital display device?
i. Pixel ii. Resolution iii. DPI iv. None of them
f. What is the resolution of 19 inch common widescreen monitor?
i. 920 X 1080 ii. 1680 X 1050 iii. 2560 X 1440 iv. 1920 X 1080
g. Which of the tools is used to crop an image and remove unwanted areas?
i. Slice tool ii. Polygonal tool iii. Magic wand tool iv. Crop tool
h. Which tool is used to click and drag an image around on the screen to view
different areas when zoomed in?
i. Zoom tool ii. Hand tool iii. Line tool iv. Rotate view tool
i. Which tool is used to remove unwanted areas of an image?
i. Crop tool ii. Clone stamp tool iii. Eraser tool iv. Blur tool
j. Which of the following is used to insert text in the image?
i. Clone stamp tool ii. Magic wand tool iii. Line tool iv. Type tool
New Gateway to Computer Science Book -9 99
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