GIF images are compressed using the Lempel–Ziv–Welch lossless data compression technique to reduce the file size without degrading the visual quality.
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14 Facts About GIF
2.
CompuServe encouraged the adoption of GIF by providing downloadable conversion utilities for many computers.
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3.
GIF was one of the first two image formats commonly used on Web sites, the other being the black-and-white XBM.
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4.
Conceptually, a GIF file describes a fixed-sized graphical area populated with zero or more "images".
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5.
Many GIF files have a single image that fills the entire logical screen.
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6.
GIF files start with a fixed-length header giving the version, followed by a fixed-length Logical Screen Descriptor giving the pixel dimensions and other characteristics of the logical screen.
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7.
Additionally, not all GIF rendering programs handle tiled or layered images correctly.
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8.
Uncompressed GIF can be a useful intermediate format for a graphics programmer because individual pixels are accessible for reading or painting.
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9.
The GIF standard allows such extra CLEAR codes to be inserted in the image data at any time.
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10.
GIF Specification allows each image within the logical screen of a GIF file to specify that it is interlaced; i e, that the order of the raster lines in its data block is not sequential.
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11.
Each frame in an animation GIF is introduced by its own GCE specifying the time delay to wait after the frame is drawn.
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12.
Unisys became aware that the version of GIF used the LZW compression technique and entered into licensing negotiations with CompuServe in January 1993.
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13.
Unisys stated that they expected all major commercial on-line information services companies employing the LZW patent to license the technology from Unisys at a reasonable rate, but that they would not require licensing, or fees to be paid, for non-commercial, non-profit GIF-based applications, including those for use on the on-line services.
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14.
Complete support for GIF is complicated chiefly by the complex canvas structure it allows, though this is what enables the compact animation features.
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