Data Compression


Criteria

Survey Formats

Basics

Compression Methods

Data Formats

Files

Audio Data

Image Data

GIF

Colours

Data Compression

Characteristics

GIF87a

GIF89a

Patents

Optimizations

Examples

Drawings

JPEG

Video Data


Glossary

Index


Download


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GIF - Drawings


One of the main fields of application for GIF are drawings, sketches, etc., which are subject to certain characteristics at the conversion:


Number of Colours

It must be guaranteed, that no colour will be rejected being essential for the picture's information.


Raster

Rastered lines, in particular if they have only the strength of one pixel, impair the picture impression considerably. Additionally the compression rate decreases.


Anti-Aliasing

Anti-aliasing results in intermediate steps increasing the number of colours. Frequently the number of colours must be manually reduced afterwards, because automatic procedures would reject important contents. Additionally the blurring negatively effect the subjective impression and the compression rate.


Background Colour

If the drawing should be fit into a background, it is advisable to define the background with transparency. Thus disturbing colour deviations will be avoided and no manual changes are necessary for later adaptions.


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GIF - Graphic Interchange Format GIF - Examples JPEG