Misplaced Pages

Adam7 algorithm: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 14:24, 5 August 2006 editSmyth (talk | contribs)Extended confirmed users, Pending changes reviewers11,815 edits Tidy up. Not a stub.← Previous edit Revision as of 17:11, 5 August 2006 edit undoSbo (talk | contribs)227 editsNo edit summaryNext edit →
Line 15: Line 15:
The subimages are then stored in the PNG file in numerical order. The subimages are then stored in the PNG file in numerical order.


Adam7 uses seven passes and operates in both dimensions, compared to only four passses in the vertical dimension used by ]. This means the whole image can be perceived much more quickly in the early passes. Adam7 uses seven passes and operates in both dimensions, compared to only four passes in the vertical dimension used by ]. This means the whole image can be perceived much more quickly in the early passes.


Adam7 is named after Adam M. Costello, who suggested the method on ], ], based on this five-pass scheme that had earlier been proposed by Lee Daniel Crocker: Adam7 is named after Adam M. Costello, who suggested the method on ], ], based on this five-pass scheme that had earlier been proposed by Lee Daniel Crocker:

Revision as of 17:11, 5 August 2006

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 this 8×8 pattern across the full image.

1 6 4 6 2 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
3 6 4 6 3 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7

The subimages are then stored in the PNG file in numerical order.

Adam7 uses seven passes and operates in both dimensions, compared to only four passes in the vertical dimension used by GIF. This means the whole image can be perceived much more quickly in the early passes.

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

1 4 2 4
5 5 5 5
3 4 3 4
5 5 5 5

External links

Category: