7 - Indira Gandhi Centre for Atomic Research

that area. It provides an improved means of progressive display through two-dimensional
interlacing and its lossless compression means that it is a good format choice for storing
intermediate-stage images. The following table shows that the sizes of the image file
formats.
3.3 Bitmap graphics (BMP)
Bitmap files are stored in a device-independent bitmap format that allows windows to
display the bitmap on any type of display device. Each bitmap file contains a bitmap-file
header, a bitmap-information header, a colour table, and an array of bytes that defines the
bitmap bits. BMP images can range from black and white up to 24 bit colour. While the
images can be compressed, this is rarely used in practice.
3.4 Joint Photographic Experts Group (JPEG or JPG)
This is a minimal file format which enables JPEG bit streams to be exchanged between a
wide variety of platforms and applications. It can reduce file sizes to about 5% of their
normal size some detail is lost in the compression and is optimized for the display of
photographs and doesn't work as well as GIF for type or line drawings. JPEG compression
gives very high compression rates with high perceived image quality and can handle high
resolution images with colour depths of 24-bit and above.
3.5 Graphics Interchange Format (GIF)
It is best used for line art such as cartoons, graphs, schematics, logos, and text that have a
limited number of colours and distinct boundaries between colour regions. It is a web
standard small file size allows images to transmit quickly over the Internet. GIF files
incorporate a compression scheme to keep file sizes at a minimum, and they are limited to
8-bit colour palettes.
4. Markup Languages
It is a form of annotation that has been used in publishing for centuries to describe the
desired effects or operations to be applied to textual content. In 1974, Charles Goldfarb
invented SGML. In the late 1980s and early 1990s, following Tim Berners-Lee's proposal,
a simplified markup language, based upon SGML, was developed for the encoding of
documents for distribution via Internet. With the effect of marketing changes SGML
having proper languages called HTML.
4.1 Standard Generalized Markup Language (SGML)
For most digital library or digital publishing SGML content, the texts are encoded not in
HTML but in more powerful and descriptive tag sets, such as the Text Encoding Initiative
Guidelines. It is a “meta-language” used to define structural markup languages
standardized (ISO 8879) in 1980s. SGML texts are comprised of plain ASCII text,
combined with items in angle brackets, e.g. Digital materials: file formats,
standards and protocols . It is both a language and an ISO standard for describing
information embedded within a document. It identifies document elements such as titles,
paragraphs, tables and chapters as distinct objects, allowing users to define the
relationships between the objects for structuring data in documents.
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