Page 50 - DCAP303_MULTIMEDIA_SYSTEMS

Multimedia Systems

notes objectives

After studying this unit, you will be able to:
• Discuss the bitmap images
• Explain the vector drawing
• Explain 3D drawing and rendering
• Discuss natural lights and colours
• Explain about computerized colours
• Define the colour palettes
• Discuss the image file formats
• Explain Macintosh image format
• Discuss the windows imaging file format
• Define the cross-platform formats

introduction

An image is an optical representation of an object produced by light rays from the object being
refracted or reflected by a lens or mirror.
An imitation, representation, or similitude of any person, thing, or act, sculptured, drawn, painted,
or otherwise made perceptible to the sight; a visible presentation; a copy; a likeness; an effigy;
a picture; a semblance. The Image Format is a base topic for topics describing a defined way of
coding information for storage or transfer of images.
Rendering is the process of adding realism to a computer graphics by adding three-dimensional
qualities such as shadows and variations in colour and shade. One technique for rendering graphics
is called ray tracing. Another type of rendering is scanline rendering, which renders images one
vertical line at a time instead of object-by-object as in ray tracing. In general, scanline rendering
does not produce as good results as ray tracing, but it is used frequently in animation packages
where the image quality of each individual frame is not so important.
Still images are the important element of a multimedia project or a website. In order to make a
multimedia presentation look elegant and complete, it is necessary to spend ample amount of
time to design the graphics and the layouts. Competent, computer literate skills in graphic art
and design are vital to the success of a multimedia project.

4.1 Bitmaps

Bitmaps are defined as a regular rectangular mesh of cells called pixels, each pixel containing a
colour value. They are characterized by only two parameters (See Figure 4.1), the number of pixels
and the information content (colour depth) per pixel. There are other attributes that are applied
to bitmaps but they are derivations of these two fundamental parameters.
figure 4.1: Bitmaps parameters
N pixels horizontally

M pixels vertically pixels

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