Display PostScript: Difference between revisions

Revision as of 18:03, 16 January 2005

Revision as of 07:49, 15 February 2005

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DPS did not, however, add a windowing system. That was left to the implementation to provide, and DPS was meant to be used in conjunction with an existing windowing engine. This was often the [[X Window System]], and in this form Display PostScript was later adopted by companies such as [[International Business Machines|IBM]] and [[Silicon Graphics|SGI]] for their workstations. Often the code needed to get from an X window to a DPS context was much more complicated than the entire rest of the DPS interface. This greatly limited the popularity of DPS when any alternative was available.

OnThe thedevelopers of [[NeXT]], wrote a completely new windowing engine was written to take full advantage of theirNeXT's [[object oriented]] [[operating system]]. A number of commands were added to DPS to actually create the windows and to react to events, similar to but simpler than [[NeWS]]. The single API made the writing of stuff at higher levels much easier and making NeXT one of the few systems to extensively use DPS. The user-space windowing system library [[NeXTStep]] used PostScript to draw items like titlebars and scrollers. This, in turn, made extensive use of <code>pswrap</code>s, which were in turn wrapped in objects and presented to the programmer in object form.

[[Apple Computer|Apple]]'s [[Mac OS X]] operating system now makes use of a similar imaging model to Display PostScript, but does not have the same level of programmability. The new system, known as [[Quartz (Macintosh)|Quartz]], is based on the [[Portable Document Format|PDF]] model in which the source of the image is not the PostScript code itself, but the result of interpreting that code. It keeps the basic graphics primitives, font handling and measurements, and in many cases looks and feels like DPS. It is not entirely clear why this switch happened, but speculation suggests that Adobe was asking for a high licensing fee.