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Revision as of 19:11, 24 October 2005 editMichael Hardy (talk | contribs)Administrators210,266 edits Fixed some incorrect capitals (see Misplaced Pages:Manual of Style); deleted extra blank space.← Previous edit Revision as of 11:36, 29 October 2005 edit undoSmyth (talk | contribs)Extended confirmed users, Pending changes reviewers11,815 edits Link to Interlace (bitmaps)Next edit →
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'''Adam7''' is the ] ] specified for use in ] images. An interlaced PNG image is broken into seven subimages, which are defined by replicating the following 8x8 pattern on the right across the full image. The subimages are stored in the PNG file in numerical order. '''Adam7''' is the ] ] specified for use in ] images. An interlaced PNG image is broken into seven subimages, which are defined by replicating the following 8x8 pattern on the right across the full image. The subimages are stored in the PNG file in numerical order.


Adam7 is a 2D interlacing scheme unlike the 1D scheme used in interlaced ]. This means the percieved quality of the image and the readablity of text in the image rises much faster in the early passes than with GIF interlacing (). Adam7 is a 2D interlacing scheme unlike the 1D scheme used in interlaced ]. This means the percieved quality of the image and the readablity of text in the image rises much faster in the early passes than with GIF interlacing ().

Revision as of 11:36, 29 October 2005

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Adam7 is the interlacing algorithm specified for use in PNG images. An interlaced PNG image is broken into seven subimages, which are defined by replicating the following 8x8 pattern on the right across the full image. The subimages are stored in the PNG file in numerical order.

Adam7 is a 2D interlacing scheme unlike the 1D scheme used in interlaced GIF. This means the percieved quality of the image and the readablity of text in the image rises much faster in the early passes than with GIF interlacing (demo animation).

Interesting points of note

  • Two-dimensional interlacing scheme
  • PNG first interlace pass displays 1/64th of the image data
  • The GIF format on the other hand displays 1/8th of the image data
  • PNG will send 4 passes to GIF's 1st pass

History

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Adam7 is named after Adam M. Costello, who suggested the method on January 30, 1995, based on a very similar five-pass scheme that had earlier been proposed by Lee Daniel Crocker.

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