) A document publishing format that was developed at AT&T in the mid-1990s. Similar to Adobe's portable document format (PDF) in that tables of contents, Web links and metadata are supported, and free readers are available to view the documents, DjVu documents take considerably less storage space than the same content in PDF. Space savings is a primary benefit, and DjVu documents render faster than PDF because only the pages being viewed need be decompressed.
DjVu Is Raster Based
DjVu pages are highly compressed bitmaps (raster images). Text and graphics are separated, and the color graphics are compressed at a low resolution using wavelet compression. Text characters are compressed as bitmaps at a higher resolution with an index to their locations on the page. Since DjVu documents are created at a target resolution, the page is less crisp when zoomed in and out to different sizes. In contrast, PDF documents use fonts and vector images that scale to the size of the window on screen without distortion. See PDF
, wavelet compression