Page 11 - DCAP109_GRAPHIC_TOOLS

Graphic Tools

Notes detail, the quality of the image is only determined by the resolution of the display, and the file
size of vector data generating the image stays the same. Printing the image to paper will usually
give a sharper, higher resolution output than printing it to the screen but can use exactly the
same vector data file.

Did u know? JPEG images don’t support transparency.

Editing Vector Graphics

Vector graphic drawing software is used for creating and editing vector graphics. The image can
be changed by editing screen objects which are then saved as modifications to the mathematical
formulae. Mathematical operators in the software can be used to stretch, twist, and colour
component objects in the picture or the whole picture, and these tools are presented to the user
intuitively through the graphical user interface of the computer. It is possible to save the screen
image produced as a bitmap/raster file or generate a bitmap of any resolution from the vector
file for use on any device.
The size of the file generated will depend on the resolution required, but the size of the vector
file generating the bitmap/raster file will always remain the same. Thus, it is easy to convert
from a vector file to a range of bitmap/raster file formats but it is much more difficult to go in
the opposite direction, especially if subsequent editing of the vector picture is required. It might
be an advantage to save an image created from a vector source file as a bitmap/raster format,
because different systems have different (and incompatible) vector formats, and some might not
support vector graphics at all. However, once a file is converted from the vector format, it is
likely to be bigger, and it loses the advantage of scalability without loss of resolution. It will
also no longer be possible to edit individual parts of the image as discrete objects.

Vector formats are not always appropriate in graphics work. For example, digital devices such
as cameras and scanners produce raster graphics that are impractical to convert into vectors, and
so for this type of work, the editor will operate on the pixels rather than on drawing objects
defined by mathematical formulae. Comprehensive graphics tools will combine images from
vector and raster sources, and may provide editing tools for both, since some parts of an image
could come from a camera source, and others could have been drawn using vector tools.

Standards

The W3C standard for vector graphics is SVG. The standard is complex and has been relatively
slow to be established at least in part owing to commercial interests. Many web browsers now
have some support for rendering SVG data but full implementations of the standard are still
comparatively rare.

Applications

One of the first uses of vector graphic displays was the US SAGE air defense system. Vector
graphics systems were only retired from U.S. en route air traffic control in 1999, and are likely
still in use in military and specialized systems. Vector graphics were also used on the TX-2 at the
MIT Lincoln Laboratory by computer graphics pioneer Ivan Sutherland to run his program
Sketchpad in 1963.
Subsequent vector graphics systems, most of which iterated through dynamically modifiable
stored lists of drawing instructions, include Digital’s GT40. There was a home gaming system
that used vector graphics called Vectrex as well as various arcade games like Asteroids and

4 LOVELY PROFESSIONAL UNIVERSITY