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Unit 7: Graphics and Multimedia
At some point, all vector graphics must be rasterized in order to be displayed on digital monitors. Notes
However, vector images can be displayed with analog CRT technology such as that used in
some electronic test equipment, medical monitors, radar displays, laser shows and early video
games. Plotters are printers that use vector data rather than pixel data to draw graphics.
7.3.2.1 Computer Graphics Metafile (CGM)
Computer Graphics Metafile (CGM) is a file format for 2D vector graphics, raster graphics, and
text, and is defined by ISO/IEC 8632. All graphical elements can be specified in a textual source
file that can be compiled into a binary file or one of two text representations. CGM provides a
means of graphics data interchange for computer representation of 2D graphical information
independent from any particular application, system, platform, or device. It has been adopted
to some extent in the areas of technical illustration and professional design, but has largely been
superseded by formats such as SVG and DXF.
7.3.2.2 Scalable Vector Graphics (SVG)
Scalable Vector Graphics (SVG) is an open standard created and developed by the World Wide
Web Consortium to address the need (and attempts of several corporations) for a versatile,
scriptable and all-purpose vector format for the web and otherwise. The SVG format does
not have a compression scheme of its own, but due to the textual nature of XML, an
SVG graphic can be compressed using a program such as gzip. Because of its scripting
potential, SVG is a key component in web applications: interactive web pages that look
and act like applications.
7.3.2.3 Others
Other image file formats of vector type include:
AI (Adobe Illustrator)
CDR (CorelDRAW)
EPS (Encapsulated PostScript)
HVIF (Haiku Vector Icon Format)
ODG (OpenDocument Graphics)
PDF (Portable Document Format)
PGML (Precision Graphics Markup Language)
SWF (Shockwave Flash)
VML (Vector Markup Language)
WMF / EMF (Windows Metafile / Enhanced Metafile)
XPS (XML Paper Specification)
7.3.3 Bitmap Formats
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. Bitmap files,
sometimes called raster files, essentially contain an exact pixel-by-pixel map of an image.
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.
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