Others pronounce it with an affricate (as in the word "giraffe"). Some English-speakers pronounce the acronym "GIF" with a plosive (as in the word "gift"). GIF images are limited to 256 colours, though it is possible to hack around this limitation, under certain circumstances, using the animation feature (see colour).
#Choosy programmers choose gif download
The optional interlacing feature, which stored image scanlines out of order in such a fashion that even a partially downloaded image was somewhat recognizable, also helped GIF's popularity, as a user could abort the download if it was not what was required. The GIF89a feature of storing multiple images in one file, accompanied by control data, is used extensively on the web to produce simple animations. When the World Wide Web gained popularity, GIF became one of the two image formats commonly used on Web sites, the other being the black and white XBM. The two versions can be distinguished by looking at the first six bytes of the file, which, when interpreted as ASCII, read "GIF87a" and "GIF89a", respectively. In 1989, CompuServe devised an enhanced version, called 89a, that added support for multiple images in a stream, interlacing and storage of application-specific metadata. The original version of GIF was called 87a. GIF became popular because it used LZW data compression, which was more efficient than the run-length encoding that formats such as PCX and MacPaint used, and fairly large images could therefore be downloaded in a reasonable amount of time, even with very slow modems.
The GIF format was introduced in 1987 by CompuServe in order to provide a colour image format for their file downloading areas, replacing their earlier RLE format which was black and white only. The latest expiration date of the GIF-related patents will most probably be Friday, 11 August 2006. Although the GIF patents will expire in the near future, PNG is still touted as a technically superior alternative, and has become the third most common image format on the web. The desire for a comparable format with fewer legal restrictions (as well as fewer technical restrictions such as the number of colours) led to the development of the PNG (Portable Network Graphics) standard.
#Choosy programmers choose gif software
Many software developers were caught by surprise when it was revealed that the GIF format had been patented by Unisys, and that they would have to pay royalties for writing programs that generated (or displayed) GIF files. Therefore GIF is normally used for diagrams, buttons, etc., that have a small number of colours, while the JPEG format is used for photographs. On the other hand the lossy JPEG format does poorly on sharp transitions like those in diagrams or text, producing highly visible artifacts and little file-size reduction. (However, there is a hack that can overcome this limitation under certain circumstances see #truecolour.) The GIF format's 256-colour limitation makes it unsuitable for photographs, though losslessly compressed photographs tend to be unacceptably large for the web anyway. GIFs are compressed files, and were adopted to reduce the amount of time it takes to transfer images over a network connection.Ī GIF file employs lossless data compression so that the file size of an image may be reduced without degrading the visual quality, provided the image fits into 256 colours.
The format was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web. Template:Infobox file format Template:Otheruses GIF (Graphics Interchange Format) is a bitmap image format for pictures with up to 256 distinct colours from the over 16 million representable in 24 bit rgb. If you look carefully at the seas you can see unevenness caused by the colour reduction using an inappropriate technique. File:Rotating earth (small).gifĪ rotating globe in GIF format. With pictures like this you can see the restriction of 256 colours.
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