Advantages of Bitmap Graphics and Disadvantages of Bitmap Solution
Chapter 6 Graphics
At the end of this chapter, you should be able... [Show More] to:
1. State the importance of graphics in multimedia applications;
2. Explain the two categories of computer graphics,
3. Name a few graphic file formats and sources of graphics.
In multimedia applications, the text element alone is not enough to convey the intended meaning.
Visual images provide a higher impact compared to just using text. Graphics play an important
role in multimedia presentations and is one of the most popular and main elements used in the
development of multimedia applications.
As the Chinese proverb says, “a picture paints a thousand words", a visual graphical display is
capable of presenting information more attractively and effectively. Graphics also accelerate the
presentation of information and provide clearer, accurate and consistent information as compared
to information that consist of only text.
6.1 DEFINITION AND THE IMPORTANCE OF GRAPHICS
Agnew and Kellerman (1996) stated that,
"Graphics are lines, circles, boxes, shadows, colours, and others, made by a drawing program."
According to the ‘Dewan Bahasa and Pustaka’ dictionary, graphics means something to do with
paintings or carvings. From these definitions we can conclude that the use of graphics in
multimedia programs is not just about beautiful paintings, but also as a source of presenting
highly effective information.
Graphics also mean the use of visuals to explain concepts that are not able or difficult to be
described with the use of text.
Attractive graphics is one of the main attractions of multimedia; in fact multimedia developers
are aware that the success of a multimedia application depends on the visual impact that is
Visualisation is an important process in the communication of information. This is because
human beings are more inclined to study, understand and remember something that is seen as
compared to something that is read or heard. Computer graphics can be divided into two
categories which are vector graphics and bitmap graphics. When developing graphics for
multimedia applications, you will use either one or both types of graphics. Before we study in
greater detail about computer graphics why don’t we look at the early history of graphics first.
The extract below relates the true experience of a famous multimedia specialist, about how he
realized the importance of graphics and visuals in multimedia presentations.
6.2 HISTORY OF GRAPHICS
The early history of graphics is frequently associated with the development of the printing
industry. When humans got to know about writing and print, human communication no longer
focused purely on verbal statements. The use of printing machines became more widespread
during the industrial revolution. At that time, graphic works and prints were made separately. For
example, arrangement of letters, production of paper, printing and binding, were of different
In 1880, the first press" New York Daily Graphic," used new graphic technology elements such
as photography. In the same year, graphic designers produced illustrated posters by using full
colours. The posters were displayed in several areas and towns in the United States and around
Europe. From 1890 until 1930, the "Avant Garde" group introduced the term "Art Nouveu." This
group pioneered the art of free style lettering which was not confined to the old method. One of
the prominent graphic designers from this group was Toulouse-Lautrec. Then, other graphic
designers emerged, such as Charles Rennie Mackintosh, Peter Benrens and Frank Lloyd Wright
with their own individual graphic creations.
The emergence of ideologies in the field of art brought a lot of changes in the creation of graphic
designs. For example, a magazine's layout was no longer confined to the traditional way that
emphasized symmetry. During the 1920's, the development of graphic designs progressed more
rapidly with the emergence of the group called, "de still group." This period was parallel to the
Russian Revolutionary period. Graphic designs became freer and communications with the
customers are considered important. Then, a group called, "Bauhaus," introduced language art
through fundamental designs.
This group introduced formal graphics education such as lines, forms and alphabets in graphic
designs. Technological development improved the quality and ways of graphic designs. To date,
graphic designs are not only presented through printing materials but in fact are more widespread
in the technology of televisions, films and computers. Nowadays, computers have taken over as
the medium to generate two dimensional and three dimensional graphic designs.
6.3 COMPUTER GRAPHICS APPLICATIONS
Manual graphics, using hands and tools such as pencils, pens, colours and airbrushes have been
in existence for a long time, but the field of computer graphics is still relatively new. Computer
graphics is an aspect of computer science and its use is widespread in the areas of engineering,
heavy industries, animation, and films. The study of computer graphics not only focuses on
drawings and animation but also on mathematics (calculus, algebra and geometry), programming
(C language or C++), computer algorithm and data structure. Besides that, in order to generate
attractive computer graphics, a high degree of imagination is also required.
Computer graphics can visualise or depict a person’s imagination on a computer screen. It aids in
the manufacturing of goods or materials such as cars, buildings, humans' artificial limbs,
computer games and simulations. Computer graphics can also provide a real picture of a house
before it is built. In fact, it can design the interior of a house to see what furniture would be
suitable to use. Thus, the time and cost in choosing furniture or renovation is reduced.
In the world of science, computer graphics can create a world which is invisible to the naked eye
or beyond reachable. For example NASA (National Aeronautics and Space Administration) has
created the topography of Planet Mars, from the data sent by the Telescope Hubble. From the
available data, scientists are able to see the molecular structure on the computer screen.
In the industrial world, computer graphics can help in the design of vehicles such as cars, vans,
aeroplanes, motorcycles, marine vessels or lorries. Before production, the vehicles' level of
safety, aerodynamic percentages, the suitable colours and the subsequent finished designs, can be
viewed via computer.
Figure 6.1: Computer applications in various fields.
In the medical field, computer graphics can help in the design of imitation limbs that is suitable
for a particular individual. In the near future, virtual reality can aid in long distance operations.
Virtual reality is also used in simulations such as aircraft simulations used to train pilots. Besides
that, virtual reality is also used by the police force to train its members on how to face a tense
situation such as in a shooting scenario.
Computer graphics are also used in other fields such as in computer games, films, advertising
and education. Now, computer graphics are not only accepted as an aspect of entertainment and
knowledge, but it also gives a picture of the technological advancement of a country. In the
world of computers, computer graphics is the most difficult field to explore because of the
infinite imagination of the artists. The computers used are highly powered and there is no limit to
the creativity of the computer graphics enthusiast.
6.4 USES OF GRAPHICS IN MULTIMEDIA
In multimedia applications, the text element alone is not enough to convey the intended meaning.
Graphics are not only able to present meanings but situations, feelings, intonations and sensory
elements in much greater detail in any situation. Graphics are used in multimedia applications in
the following circumstances:
Graphics are usually used as background and texture, whereby it acts as a
complement towards the intended meaning through its display.
Logos, images, paintings, figures and photographs in an application play a vital
role in the delivery of the meaning or concept of the multimedia application.
6.5 CATEGORIES OF GRAPHICS
Graphics can be divided into two basic categories:
a) Vector graphics
b) Bitmap graphics
Understanding the differences between the two types can help you with your work. For example,
some file formats can only accommodate bitmap images, whereas some file formats can
accommodate vector graphics.
6.5.1 Vector Graphics
Vector graphics are also known as object oriented graphics or structured graphics. It refers to any
image produced with the use of certain software and computer technology. Vector graphics are
formed from lines that follow the mathematical equations called vector. For example, a bicycle
tyre, in a vector graphic format is built from a mathematical definition- where a circle with a
given radius, set in a specific location and filled with particular colours. Although the bicycle
tyre can shift its location, change its size or colour, the quality of graphic remains the same.
Vector graphics do not depend on resolution. The size of the vector image can be changed and it
can also be printed on any printer no matter what is the resolution, without the loss of quality.
Vector graphics are most suitable for text (especially small text) and thick graphics (bold) which,
when altering its size, the quality still remains the same. For example is logos.
Among the applications that provide the environment based on vector graphics are Macromedia
Freehand, Adobe lllustrator and Corel Draw.
Advantages of Vector Graphics Disadvantages of Vector Graphics
Requires only a small size data for image
Quality of the Vector graphics remains the
same even though the size and the position
Requires only a small storage space.
Not realistic because of the computer
The more complex the image created the
bigger the file size and the slower the display.
Table 6.1: Advantages and Disadvantages of Vector Graphics
6.5.2 Bitmap Graphics
Bitmap graphics is also known as raster image or bit map image. Bitmap images are produced
from dots arranged specifically in metric form. These dots are known as pixels (Pixel = picture +
element). This pixel image is known as bitmap image. Within the confines of metric, these pixels
are arranged according to size, colour and location. The image created on the computer screen is
the combination of all these pixels.
Each pixel or dot that forms the bitmap image consists of 3 colours: red, green and blue or is
more popularly known as RGB (Red, Green, Blue). Nevertheless, these pixels may also consist
of black and white (monochrome) or grey colour or have 256 colours up to 16 million colours.
The more colours that are used for an image, the closer the resemblance of the image to the real
image. Bitmap images are usually not produced by computer. Instead, it is obtainedfrom an
actual source and then translated into digital form by devices such asimage scanners, digital
camera and others.
The followings are some of the ways that might be used to produce a bitmap image:-
(a) Producing the image from scratch by using computer drawing programs such as the Paint
(b) Capturing the image direct from the screen (screen capture) and then pasting the image onto
your computer drawing program or application.
(c) Taking the image of a photograph, drawing or television image by using a scanner or a video
capture card to digitize the image.
Among the applications that are used to edit or modify a bitmap image are Adobe Photoshop,
Macromedia X-Res and Painter. The bitmap image produced may be copied, modified, delivered
via e-mail and used in various creative ways.
Advantages of Bitmap Graphics Disadvantages of Bitmap Graphics
- Produces real quality image.
- Capable of storing a large amount of
- Capable of being modified with a high
- Depends on resolution
- Enlargement of image size will
produce a blurred image
Table 6.2: Advantages and Disadvantages of Bitmap Graphics
6.5.3 Vector Graphics vs. Bitmap Graphics
The choice of using either a bitmap image or a vector image is a creative decision. It also
depends on the application software used to develop the multimedia project. An image that
requires complex editing, precise and flexibility would be better drawn using a vector based
application. Vector graphics are regularly used in technical areas such as CAD/CAM (Computer
Aided Design/ Manufacture), scientific modeling, architecture, arts design and others. On the
other hand, for an image that needs to look realistic, a bitmap application is background texture.
The appearance of both of these images also depends on the resolution display and capability of
your graphics tools and the monitor of your computer. Both these images can be kept in various
types of file formats and can be translated from one application to another or from one platform
to another. Autotracing is a technique where a bitmap image is converted into a vector image. An
example of the software used for this process is Streamline from Adobe. Other than that, the file
image can also be compressed to save memory and disk space; in fact many image formats use
this compression method in their files such as GIF, JPEG and PNG file format.
Figure 6.2 Differences between Vector and Bitmap Image
6.6 GRAPHICS CARD
The monitor or the computer screen is like an electronic canvas for computers where all
multimedia images are displayed regardless whether it is a still image, an animation or a video
image that moves. Therefore, the computer monitor is the most important component of the
whole computer system. Through the monitor, you can view the results of your creation or your
The monitor and the central processing unit are connected to each other through a graphics card
located in the motherboard. Do you know that the image produced by graphics software is in
digital format? But a computer monitor can only display images in analog format. Therefore,
there is a need for a conversion process and this is the job of the graphics card.
Figure 6.3: NVIDIA GeForced4 MX 460 Graphics Card
Source : http://www.hothardware.com/reviews/ images/nv25- nv17/gf4mxboardlrg .htm
The function of a graphics card is to convert digital images to analog form and then displays it on
the monitor screen. The graphics card is also known as the video controller/adapter card because
it also plays a role in displaying video graphics. Most importantly, regardless of what it is called,
its function is still the same: that is to display your image.
A Graphics card is also responsible for:
a) Your computer's resolution
b) The number of colours that your monitor can display and the depth of colour.
Resolutions (In pixels) Type of Monitor
640 X 200 CGA (Colour Graphics Adapter)
640 X 350
640 X 480
EGA (Enhanced Graphics Adapter)
VGA (Video Graphics Adapter)
800 X 600 or
1024 X 768
SVGA (Super VGA)
Table 6.3: Types of Monitors and Resolutions
6.6.1 Colour Depth
The graphics card on the computer determines how many colours are available for display on a
computer screen. The number of colours on the computer screen is known as colour palette and it
is determined by the depth of bits of your graphics card. Each pixel is produced by a combination
of the three primary colours that is red, green and blue (RGB). The bit depth or colour depth
refers to the range of existing colours in a pixel or the number of different colours that exists on
Bit is an abbreviation for Binary digit (BInary digiT) and it comprises of 0 and 1. If your pixel
can only hold 1 bit of information, this means your monitor would only be able to display 2
colours, black and white (monochrome). If each pixel can hold two bits of information, each bit
would have two colours and both the bits will produce four colours (2 x 2). A 4-bit display will
gives you 16 colours (2x2x2x2) and an 8-bit display will give you 256 colours. The greater the
number of bits in a pixel, the more colours in the palette. Therefore, the displayed image will be
more colourful and realistic.
Colour Depth /Bit of a
24-bit 16,777 216 colours (photo realistic)
16-bit 65,536 colours (excellent for colour images)
8-bit 256 colours (good enough for colour images)
14-bit 16 colours
2-bit 4 colours
1-bit 2 colour (black and white/combination of any
Table 6.4: The Colours Available in Colour Palettes
Figure 6.4: The Colour Table of the Adobe Photoshop software
Source: http://www.webdevelopersjournal.com/articles/color in photoshop.html
6.7 GRAPHICS FILE FORMAT
To produce graphics, you don’t just require knowledge and expertise in this field but you must
also be capable of manipulating the graphics by using specific equipment to add various effects.
Different graphics software or packages will produce different file types. Fortunately, most
authoring software today is able to import and export graphics files in various formats. This
enables graphic designers to try different file formats for the different needs of the applications.
The table below shows a few graphics file format available. Each file format contains its own
distinctive features, advantages and disadvantages.
File Formats Explanations
.bmp Windows’s Bitmap; This BMP’s file is a file format
that is most efficiently used in the Windows
-gif Graphics Interchange Format (GIFs) developed by
CompuServe to be used in computer networks. GIF is
one of the most common graphics format used for
images on websites.
-jpg JPEG’s image, named after the standard committee that
developed it which is the Joint Photographic’s Experts
Group. It aimed to be a graphics format that is not
platform specific (Platform Independent). This is the
most popular graphics file format used on websites.
.pcd Photo CD; based on Photo CD technology from Kodak.
Consists of five types of sizes for each picture, from
“wallet” to “poster” size.
-pict Standard format for an image in the Macintosh
environment. It is used for the development of crossplatform.
-png Portable Network Graphic format is called ping .png is
developed as a patent and license-free format and is an
alternative format to GIF.
-tiff Tagged Image File Format (IFF) is developed by Aldus
Corporation and consists of many file versions. Usually
used in desktop publishing software packages and is a
file format favoured by printing companies.
-eps Encapsulated PostScript is a file format used in
PhotoShop and can contain both bitmap graphics and
vector graphics. It is supported by many graphics
programs, illustrations and layout pages. It is also used
to transfer PostScript’s language artworks between
Table 6.5: Graphics File Formats
A good multimedia designer should familiarize him/herself to work with various graphics file
formats. For example, one can produce graphics using Photoshop first, and then export the
graphics in JPEG format to be combined into a multimedia application.
6.8 SOURCE OF GRAPHICS
Using digital image or graphics in a multimedia presentation is not an easy task. You not only
need to think about the kind of images (graphics and / or text) to be used in the application, but
also about the legal issues involved. For example intellectuals property such as art works and
customized image have copyright issues that may limit the usage of the images. Therefore,
proper planning is required as to how to obtain graphics images for a multimedia presentation
without violating any laws.
The followings are some of the source to obtain the required images or graphics for a multimedia
Figure 6.5: Sources of Graphics
Scanning an image or photograph for use in a multimedia presentation is one way of getting
images for readymade applications. Scanner is an equipment that is able to change images, text,
drawings and photographs from analog to digital forms. A good quality scans depend on the
number of resolutions of the scanner.
A scanner can digitize and convert graphics to bitmap images on the computer. It can also
convert text document to files that can be manipulated by the computer.
b) Use of digital cameras
A digital camera can produce a digital image quickly and easily. With a digital camera, we do
not need a scanner. The captured images are in digital form and can be uploaded into a computer
instantly. These images may be manipulated and kept in a popular file format and can be
imported into a authoring software when needed. Examples of available digital cameras in the
market are Apple Quick Take and Kodak DCS 300.
c) Clip Art, Photoshop and Photo CDs
The easiest way to obtain an image is through the use of ClipArt, Photoshop and photo CDs.
These images can be obtained commercially and are usually royalty free.
Figure 6.6: Microsoft Clip Organiser
Clip Art can be obtained from CD-ROMs and through online services. Clip Art and useful
graphics are bundled together with many graphics applications; in fact many companies will
send the collection once you register your purchased product. The collection of Clip Art may
contain a mixture of many images or a series of graphics, photographs, sounds and videos related
to a single theme or a certain topic.
For example, Corel and Micrografix have many collections of Clip Art that are bundled together
with an image editing software produced by the company.
a) Producing your own image
You can produce your own image or hire graphic designers to create the image that you require.
Graphic designers are trained to capture the images in your mind to digital reality form. With the
aid of sophisticated graphics software available in the market, graphic designers can produce
attractive images with unlimited creativity.
6.9 GRAPHICS SOFTWARES
There are a lot of existing graphics software in the market. Among the most popular and
regularly used are Adobe Photoshop, Corel Draw, Painter 3D, AutoCAD and Macromedia
Freehand. Each of this graphics software has its own distinctive features and functions as shown
in Table 6.6.
Adobe Photoshop ‐ Complex graphics software and is used for
editing and manipulation of images.
- To process/retouch photos and provides
various special effects such as Paint
Effects and filter.
- For drawing and creating simple geometric
- Is used for creating images that need to be
edited in terms of its colours, size, etc
- This software can also be used to
- Is used in colouring programs, to create
real and original artwork.
- Normally provides tools such as brushes,
pens, colour spray etc, required by artists.
Table 6.6: Graphics Software
In fact, all the three categories of this graphics software are interdependent. Software such as
Adobe Photoshop (Figure 6.7), for example, is included in various categories.
Figure 6.7: The main interface of Photoshop
Development in information technology and multimedia has made graphics as a practical media
and it will continue to play a vital role in the information industry. In this digital era, graphics
have been used in several fields such as science, engineering, medical, business, industrial,
government, arts, entertainment, advertising, education and training. Attractive and relevant use
of graphics ensures the successful development and uses of software especially for education and
learning. [Show Less]